1 | Energy Efficiency and Renewable Energy eere.energy.gov

CUAC/CWAF ASRAC Working Group

Second Meeting

May 11 & 12, 2015

Department of Energy

Building Technologies Program
2

Agenda

1. Introduction and Background 

2. CWAF Status and Issues

3. CUAC Engineering Analysis

4. CUAC Energy Use Analysis

5. CUAC LCC/PBP Analysis

6. Wrap-Up
3

Summary of Ground Rule Decisions

• Alternate working group members are allowed and can vote.

– Designated by main member by May 1.

– Follow the proceedings to remain fully briefed.

• Working group members may call on members of the public.

• Quorum: 12 of 17 members (including webinar participants).

• Consensus: Less than 3 “No” votes. 

• Voting by proxy not allowed, but voting can be provided by 

phone or email if necessary in extenuating circumstances.

• “No” voters must explain their concern and offer alternatives.
4

Topics to Cover in Meetings

• CUAC

– Engineering Revisions

– Energy Use Revisions

– Shipments Revisions

– Present new analytical results (LCC, NIA, MIA)

– Vote on standard levels

• CWAF

– Status Report

– Analytical Issues to Discuss

– Vote on standard levels

• Topics not part of working group scope

– Test procedures

– Certification and compliance
5

Schedule

Date Type Presentation/Discussion Topics

4/28 Tuesday In Person • Process, ground rules 

• Work plan for engineering and energy use

5/7 Thursday N/A • Updated shipments data provided to 

analytical team

5/11 Monday 

5/12 Tuesday (AHRI)

In Person • Present revised engineering/energy use/LCC

• Stakeholder discussion

5/20 Wednesday

5/21 Thursday (L’Enfant)

In Person • Present preliminary shipments/NIA/MIA 

revisions

6/1 Monday

6/2 Tuesday

In Person • Discussion of revised shipments/NIA/MIA

• Initial negotiations of standard levels

6/9 Tuesday

6/10 Wednesday

In Person • Finalize standard levels

6/15 Monday N/A • Term sheet due: Recommended standard 

levels for all CUAC and CWAF equipment 

classes
6

Agenda

1. Introduction and Background 

2. CWAF Status and Issues

3. CUAC Engineering Analysis

4. CUAC Energy Use Analysis

5. CUAC LCC/PBP Analysis

6. Wrap-Up
7

Engineering Analysis

Gas-fired CWAF

Efficiency

Levels

Design Options

Increased Primary Heat 

Exchanger Surface area

Addition of Condensing 

Secondary Heat Exchanger

Baseline: 80% TE - -

EL1: 81% TE X -

EL2: 82% TE X -

Max-tech: 92% TE X

Oil-fired CWAF

Efficiency

Levels

Design Options

Increased Primary Heat 

Exchanger Surface area

Addition of Condensing 

Secondary Heat Exchanger

Baseline: 81% TE - -

EL1: 82% TE X -

Max-tech: 92% TE X

• Design options assumed to be implemented at each efficiency level:
8

Engineering Analysis

266.25

270.84 275.89

879.11

0

100

200

300

400

500

600

700

800

900

1000

78 80 82 84 86 88 90 92 94

MPC (2013$)

Thermal Efficiency (%)

• Gas-fired CWAF MPCs
9

Engineering Analysis

1679.63

1703.88

2339.42

1000

1200

1400

1600

1800

2000

2200

2400

2600

80 82 84 86 88 90 92 94

MPC (2013$)

Thermal Efficiency (%)

• Oil-fired CWAF MPCs
10

Engineering Analysis – Key Assumptions and Potential Changes

• DOE assumed HX material does not change at 81% and 82% TE. To maintain 

reliability/durability of designs and handle condensate, comments 

suggested DOE should consider including:

– Heat exchanger made of corrosion-resistant material

– More powerful corrosion-resistant combustion air inducer

– Condensate management system

• Based on observations in teardown units, DOE assumed cabinet size would 

not change within higher efficiency units in the non-condensing range to 

accommodate larger heat exchanger tubes.

– Commenters asserted that a larger cabinet would be needed to account for HX 

size changes.

• Analysis was conducted at one representative capacity (250,000 Btu/h). 

– Comments suggested larger capacities be analyzed separately in the 

engineering analysis due to lower production volumes and higher incremental 

costs to increase efficiency.
11

Life-Cycle Cost and Payback Period Analysis

LCC and PBP Analysis Results

Gas-fired Commercial Warm Air Furnace

EL TE

Life-Cycle Cost (2013$) Life-Cycle Cost Savings Median 

Payback 

Period 

(years)

Average 

Installed Cost

Average 

Lifetime 

Operating 

Cost

Average 

LCC

Average 

Savings 

(2013$)

% Buildings with

Net Cost No 

Impact

Net 

Benefit

0 80% $2,262 $26,623 $28,885 N/A 0% 100% 0% N/A

1 81% $2,271 $26,343 $28,613 $186 1.4% 33.1% 65.6% 0.6

2 82% $2,280 $26,069 $28,349 $426 1.9% 9.7% 88.4% 0.7

3 92% $3,848 $23,898 $27,746 $1,025 48.4% 1.1% 50.6% 12.2

EL TE

Life-Cycle Cost (2013$) Life-Cycle Cost Savings Median 

Payback 

Period 

(years)

Average 

Installed Cost

Average 

Lifetime 

Operating 

Cost

Average 

LCC

Average 

Savings 

(2013$)

% Buildings with

Net Cost No 

Impact

Net 

Benefit

0 81% $6,504 $67,313 $73,817 N/A 0% 100% 0% N/A

1 82% $6,556 $66,754 $73,310 $164 7.6% 68.9% 23.4% 2.8

2 92% $8,008 $62,187 $70,195 $3,278 46.7% 0.0% 53.3% 7.5

Oil-fired Commercial Warm Air Furnace
12

Purpose: represent the labor and material costs necessary to install the equipment.

Installation Location: Gas-fired: 95% outdoors, 5% indoors; Oil-fired: 100% indoors

Sources: 2013 RS Means (Mechanical Cost Data) , manufacturer literature, and 

information from experts.

Life-Cycle Cost and Payback Period Analysis

Installation Costs

Basic Installation 

Costs

Condensate 

Withdrawal Installation 

Costs

Venting Installation

Costs (Indoor)

Individual 

Building 

Installation Cost - Pipe

- Pump

- Condensate Neutralizer

- Heat Tape

- Electric Outlet

- Putting in Place & Setting 

Up Furnace

- Gas or Oil Piping

- Ductwork Hookup

- Electrical Hookup 

(Thermostat)

- Permit & Removal/Disposal 

Fees
13

Installation Fractions and Average Costs for Condensate Removal

Life-Cycle Cost and Payback Period Analysis

Condensing CWAF: Condensate Removal

Installation 

Cost Description Criteria

Frequency 

of 

applying 

criteria

Average 

Cost

CGWAF

Weighted

Cost

CGWAF

Condensate 

Pipe

Drain excess condensate All installations 100% $170 $170

Condensate 

Pump*

Pump condensate to a 

remote drain

Replacement 

installations 

without CUAC

50% $262 $131

Freeze 

Protection*

Protect condensate from 

freezing temperatures

Outdoor

installations 100% $51 $51

Electrical 

Outlet 

(additional) 

Some installations requiring

pump or freeze protection 

need additional outlet

Installations 

requiring a pump 

or heat tape

50% $253 $125

Condensate 

Neutralizer

Neutralizes acidic 

condensate before draining

Fraction of all 

installations 12.5% $75 $9.3

* Accounted for additional energy use
14

Base-Case Efficiency Distribution

Purpose: Reflects the projected market share of equipment at different efficiency levels in 

the base case (in the absence of standards).

• Not all commercial consumers purchase equipment at current minimum standard.

• Commercial consumers already purchasing equipment at efficiencies greater than or equal to a 

prospective standard level are not impacted by the standard.

Method: Projected CWAF efficiency market share in 2018 for each equipment class based on 

the share of models in each product class from the latest AHRI certification directory.

Life-Cycle Cost and Payback Period Analysis

EL Design Option Base Case Market 

Share in 2018 (%)

Gas-fired Commercial Warm Air Furnace Outdoor Indoor

0 80% TE – Baseline 70 4

1 81% TE – Increased HX Area 20 93

2 82% TE – Increased HX Area 9 4

3 92% TE – Condensing (Max Tech) 1 0

Oil-fired Commercial Warm Air Furnace

0 81% TE – Baseline 31

1 82% TE – Increased HX Area 69

2 92% TE – Condensing (Max Tech) 0

Note: Components may not sum to 100% due to rounding.
15

• Equipment below standard will “roll-up” to comply with standards. Equipment at or 

above the standard will not be affected.

Base Case Efficiencies

National Impact Analysis

Projection of Base-Case Efficiency Distribution of 

New Units for Gas-fired CWAF

Efficiency Level

Market Share (percent)

Base 

Case

Efficiency Level (EL)

1 2 3

CGWAF

0 80% Baseline 67

1 81% 24 90

2 82% 9 9 99

3 91% 1 1 1 100

COWAF

0 81% Baseline 31

1 82% 69 100

2 92% 0 0 100

Commercial Applications

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Base Case Efficiency Distribution

EL 3

EL 2

EL 1

EL 0

Note: Components may not sum to 100% due to rounding.
16

Shipments Analysis

Historical and Projected Base Case Shipments for CWAF

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

Shipments (million)

Oil-fired Commercial Warm Air Furnace

Gas-fired Commercial Warm Air Furnace

Historical Projected
17

Equipment Class Trial Standard Levels

1 2 3 4 5

Thermal Efficiency (TE)

Gas-Fired Commercial 

Warm Air Furnace 81% 81% 82% 82% 92%

Oil-Fired Commercial 

Warm Air Furnace 81% 82% 81% 82% 92%

National Impact Analysis

TSL Selection Criteria for each product class:

• TSL 5: Max-tech efficiency levels

• TSL 2-4: Combinations of intermediary efficiency levels

• TSL 1: Most common efficiency level above the baseline for gas-fired CWAF and at the baseline 

for oil-fired CWAF.

Trial Standard Levels (TSLs)

TSL4 is Proposed TSL
18

Equipment Class TSL 1 TSL 2 TSL 3 TSL 4 TSL 5

Primary Energy 

Savings

Gas-fired CWAF 0.203 0.203 0.471 0.471 3.040

Oil-fired CWAF 0.000 0.001 0.000 0.001 0.031

Total* 0.203 0.204 0.471 0.472 3.071

Full-Fuel-Cycle 

Energy Savings

Gas-fired CWAF 0.222 0.222 0.516 0.516 3.338

Oil-fired CWAF 0.000 0.001 0.000 0.001 0.036

Total* 0.222 0.223 0.516 0.517 3.374

National Impact Analysis

National Energy Savings (quads) TSL4 is Proposed TSL

Product Class Discount Rate TSL 1 TSL 2 TSL 3 TSL 4 TSL 5

Gas-fired CWAF

3%

1.139 1.139 2.643 2.643 10.008

Oil-fired CWAF 0.000 0.016 0.000 0.016 0.376

Total * 1.139 1.155 2.643 2.659 10.384

Gas-fired CWAF

7%

0.436 0.436 1.011 1.011 2.780

Oil-fired CWAF 0.000 0.006 0.000 0.006 0.122

Total * 0.436 0.442 1.011 1.017 2.902

Net Present Value of Consumer Benefit (billion 2013$)
19

Agenda

1. Introduction and Background 

2. CWAF Status and Issues

3. CUAC Engineering Analysis

4. CUAC Energy Use Analysis

5. CUAC LCC/PBP Analysis

6. Wrap-Up
20

Energy Conservation Standards Rulemaking Process

RFI NOPR Final 

Rule
21

Summary of Analysis Approach Revisions--Equipment

Issue Approach Revisions Additional Input 

Required

Single-circuit vs. dualcircuit for 7.5 ton 

baseline and EL1

Analysis of both single- and dual-circuit for 

baseline 7.5 ton.

Appropriate 

shipment 

distribution.

Conversion curbs: 

Cost and 

performance impact

0.2 in wc conversion curb pressure drop.

Conversion curb required at EL3 for 

replacements.

Cost estimates to be discussed.

None

Additional efficiency 

levels

Added new ELs and redesignated ELs:

Baseline: 1- and 2- compressor for 7.5 ton

EL1 CAV and EL1 SAV

EL2 CAV and EL2 SAV

EL2.5: halfway between EL2 and EL3

EL3

EL3.5: for 7.5 and 15 ton, 0.7 to 1.0 above EL3

EL4: recently called EL3.1, called EL4 in NOPR

EL5: Max tech

Final consensus 

on ELs for 

analysis
22

Engineering Analysis Status Overview

• Added analyses for additional ELs and models.

– 1- and 2-compressor 7.5 ton baseline models.

– EL2.5 for all classes and EL3.5 for small and large classes.

• Slight adjustments in some of the 15-ton results.

• Developed energy use results for 7.5 models. Work on 30 ton 

models is ongoing.

• 30-ton Baseline EL raised to 10.6 IEER.

• Evaluated differences between VAV and SAV for 15-ton EL3.

• Identified to specific manufacturers which of their 15-ton 

models are used in the analysis.

• Reviewed unit size trends.

• Refined cost curves for 7.5 and 15 ton models.

• Developed cost curves for 30 ton models.

• Developed shipping cost and average unit weight estimates by 

class/EL.
23

Description of Units--15-ton

Unit Rating Compressor

EL Target 

IEER IEER/EER Net Capacity 

(IDCFM/ODCFM) # Model

Baseline 11.2 11.2/11 176,000 (5,750/12,000) 2 (2Stages) ZP76

EL1 CAV 12.4 12.2/11 176,000 (5,300/11,000) 2 (2Stages) ZP103+ZP49

EL1 SAV 12.4 12.6/11 174,000 (5,250) 2 (2Stages) ZP76

EL2 CAV 13.2 13.2/12.2 174,000 (4,900) 2 (2Stages) ZP76

EL2 SAV 13.2 13.2/11 176,000 (5,300/11,000) 2 (2Stages) ZP103+ZP49

EL2.5 (SAV) 13.7 13.7/12.0 172000 (5250/16000) 3 (2Stages) ZP51

EL3 14.2 14.2/12 172,000 (5,300/11,700) 2 (3Stages) ZP90+ZP49

EL3.5 15.0 15/12.1 174000 (5250/11700) 2 (3Stages) ZP90+ZP49

EL4 18.5 18.5/12.6 174,000 (4,875) 2 (3Stages) 

(1circuit) ZP90+ZP49

EL5

Maxtech 20.1 20.1/12.7 172,000 (5,250/11,700) 1VS+2FixSpd ZPV34+2*ZP44

• The OD and ID heat exchanger designs of the EL1 units have been adjusted 

using CoilDesigner/VapCyc to match the IEER targets.
24

15-ton Units: Outdoor Heat Exchangers and Fans

OD HX OD Fan

EL IEER Face Area (FPI) Row*# Speed+Type #*hp

Baseline 11.2 41.4 (23) 1 -MCHX FixedSpeed+PSC 3*0.33

EL1 CAV 12.4 35.2 (20) 1-MCHX 

adjusted to 36.8 (23) 1 ** FixedSpeed+PSC 2*0.5

EL1 SAV 12.4 23.1(17) 2*2-TFHX 

adjusted to 22.2 (15) 2*2 ** FixedSpeed+PSC 3*0.25

EL2 CAV 13.2 21.4 (17) 2*2-TFHX FixedSpeed+PSC 3*0.25

EL2 SAV 13.2 35.2 (23) 1-MCHX FixedSpeed+PSC 2*0.5

EL2.5 (SAV) 13.7 55.2 (23) 1-MCHX FixedSpeed+PSC 4*0.33

EL3 14.2 42.6 (20) 1-MCHX FixedSpeed+PSC 2*0.5

EL3.5 15.0 42.6 (20) 1-MCHX FixedSpeed+PSC 2*0.5

EL4 18.5 29.6 (18) 2*2-TFHX Staged+ECM 4*0.33

EL5

Maxtech 20.1 42.6 (20) 1-MCHX VS+ECM 2*0.5

**Adjusted using CoilDesigner/VapCyc to match the IEER targets.

OD fan staging: All 1-stage, except for EL4 (100%/80%/70%) and EL5 

(100%/70%)
25

15-ton Units: Indoor Heat Exchangers and Fans

ID HX ID Fan

EL IEER Face Area (FPI) Rows Speed+Type hp

Baseline 11.2 18.6 (14) 3 FixedSpeed+Belt 3

EL1 CAV 12.4 26 (15) 3 

adjusted to 26.4 (17) 3 ** FixedSpeed+Belt 3

EL1 SAV 12.4 17.5 (15) 3 

adjusted to 17.2 (14) 3 ** Staged+Belt 2.9

EL2 CAV 13.2 22 (15) 4 FixedSpeed+Belt 2.2

EL2 SAV 13.2 26 (15) 3 Staged+Belt 3

EL2.5 (SAV) 13.7 21.4 (14) 3 Staged+Belt 3

EL3 14.2 31.4 (15) 3 Staged+Belt 3

EL3.5 15.0 31.4 (15) 4 Staged+Belt 3

EL4 18.5 26 (15) 4 Staged+Belt 2.9

EL5

Maxtech 20.1 31.4 (15) 4 Staged+Belt 3

**Adjusted using CoilDesigner/VapCyc to match the IEER targets.

ID fan staging: 1-stage for CAV (Baseline, EL1 CAV, EL2 CAV);

 100%/60%/40% for EL4; 100%/67% all others.
26

Description of Units--7.5-ton

Unit Rating Compressor

EL Target 

IEER IEER/EER Net Capacity 

(IDCFM/ODCFM) # Model

Baseline-1 11.4 11.4/11.2 90,000 (2,500/5,300) 1 (1stage) ZP76

Baseline-2 11.4 11.5/11.3 88,000(3,000/7,200) 2 (2stage) ZP38K5E

EL1 CAV 12.9 13.0/12.7 90,000 (3,000/8,800) 2 (2stage) ZP34K5E

EL1 SAV 12.9 13.0/11.2 83,000 (2,250) 2 (2stage) ZP36

EL2 CAV 14.0 14.0/13.0 92,000 (2,600/8,000) 2 (2stage) ZP36K5E

EL2 SAV 14.0 14.0/12.7 90,000 (2,800/8,800) 2 (2stage) ZP34

EL2.5 (SAV) 14.5 14.5/12.6 89,000 (2,625/6,800) 2 (3stage) ZP44 and ZP28

EL3 14.8 14.7/12.5 99,000 (2,720/6,800) 2 (3stage) ZP49 and ZP31

EL3.5 15.8 15.8/13.0 92,000(2,600/8,000) 2 (2stage) ZP36

EL4 19.9 19.9/13.1 89,000 (2,625) 2 (3stage)

1-circuit ZP44+ZP28

EL5

Maxtech 21.5 21.5/13.9 92,000 (2,800/10,250) 2 (2stage)

1-circuit ZP34

• The OD and ID heat exchanger designs of the Baseline (dual-compressor), 

EL1, and EL3 units have been adjusted using CoilDesigner/VapCyc to match 

the IEER targets.
27

7.5-ton Units: Outdoor Heat Exchangers and Fans

OD HX OD Fan

EL IEER Face Area (FPI) Row*# Speed+Type #*hp

Baseline-1 11.4 24.2 (23) 1*1 MCHX FixedSpeed+PSC 1*0.5

Baseline-2 11.4 28.8 (27) 2*1 TFHX 

adjusted to 28.4 (26) 2*1 ** FixedSpeed+PSC 2*0.25

EL1 CAV 12.9 29.3 (20) 3*1 TFHX 

adjusted to 28.72 (19) 3 ** FixedSpeed+PSC 2*0.33

EL1 SAV 12.9 20.5 (17) 2*1 TFHX 

adjusted to 20.2 (16) 2*1 ** FixedSpeed+PSC 2*0.25

EL2 CAV 14.0 27 (23) 1 MCHX*1 FixedSpeed+PSC 2*0.33

EL2 SAV 14.0 29.3 (20) 3*1 TFHX FixedSpeed+PSC 2*0.33

EL2.5 14.5 20.8(20) 1*1 MCHX FixedSpeed+PSC 1*0.75

EL3 14.8 20.8(20) 1*1 MCHX 

adjusted to 21 (21) 1*1 ** FixedSpeed+PSC 1*0.75

EL3.5 15.8 27 (23) 1*1 MCHX FixedSpeed+PSC 2*.33

EL4 19.9 36.1 (18) 2*1 TFHX Staged+ECM 3*0.33

EL5

Maxtech 21.5 40.8 (20) 2*1 TFHX Staged+ECM 3*0.33

**Adjusted using CoilDesigner/VapCyc to match the IEER targets.

OD fan staging: All 1-stage, except for EL4 (100%/80%/70%) and EL5 

(100%/50%)
28

7.5-ton Units: Indoor Heat Exchangers and Fans

ID HX ID Fan

EL IEER Face Area (FPI) Rows Speed+Type hp

Baseline-1 11.4 9.7 (14) 4 FixedSpeed+Belt 1

Baseline-2 11.4 8.9 (16) 4 adjusted to 8.7 (16) 4 ** FixedSpeed+Belt 1.5

EL1 CAV 12.9 12.8 (14) 4 adjusted to 12.3 (13) 4 ** FixedSpeed+Belt 1.5

EL1 SAV 12.9 8.9 (15) 3 Staged+Belt 1.7

EL2 CAV 14.0 13.5 (15) 3 FixedSpeed+Belt 2

EL2 SAV 14.0 12.8 (14) 4 Staged+Belt 2

EL2.5 14.5 12.4 (16) 4 Staged+Direct 3.75

EL3 14.8 12.4 (16) 5 adjusted to 12.8 (17) 5 ** Staged+Direct 3.75

EL3.5 15.8 13.5 (15) 3 Staged+Belt 2

EL4 19.9 17.5 (15) 4 Staged+Belt 1.7

EL5 Maxtech 21.5 13.5 (14) 4 Staged+Direct 3.75

**Adjusted using CoilDesigner/VapCyc to match the IEER targets.

ID fan staging: 1-stage for CAV (Baseline, EL1 CAV, EL2 CAV);

 100%/67% all others.
29

Description of Units—30-ton

Unit Rating Compressor Refrigerant 

EL Circuits Target 

IEER IEER/EER Net Capacity 

(IDCFM/ODCFM) # Model

Baseline 10.6 10.6/10.0 386,000(10,500/NA) 2 (2Stage) ZP182 2

EL1 CAV 11.6 11.5/10.8 354,000 (9,600/21,500) 4 (2 Stage) ZP76 4

EL1 VAV 11.6 11.5/10.3 334,000 (9,000/NA) 2 (2 Stage) ZP154 2

EL2 CAV 12.5 12.5/10.6 336,000 (9,000/25,800) 3 (5 Stage) ZP72*2+ZP120 1

EL2 VAV 12.5 12.4/10.1 308,000 (8,250/19,500) 4 (4 Stage) ZP72 2

EL2.5 CAV 13.2 13.2/11 360,000(8,700/NA) 2 (2Stage) ZP137 and ZP154 1

EL2.5 VAV 13.2 13.2/10.1 368,000(8,750/19,500) 4 (4 Stage) 2 ZP67 and 2 ZP103 2

EL3 13.5 13.5/10.8 354,000 (9,600/21,500) 4 (4 Stage) ZP76 4

EL4 14.9 14.9/11.0 360,000 (8,700) 2 (2 Stage) ZP137 and ZP154 1

EL5

Maxtech 15.6 15.6/10.7 435,000(12000/NA) VS+2Fixed 

Speed 2

Baseline IEER raised to 10.6 for 30-ton units because 10.1-IEER units are not 

major-manufacturer units, and little information is available for them. 

The OD and ID heat exchanger designs of both EL1 and the EL2 VAV units will be 

adjusted using CoilDesigner/VapCyc to match the IEER targets.

Some of the listed unit details may be revised depending on available 

information.
30

30-ton Units: Outdoor Heat Exchangers and Fans

OD HX OD Fan

EL IEER Face Area (FPI) Row*# Speed+Type #*hp Stages

Baseline 10.6 33.3(20)1*1 MCHX Fixed-3Phase 2*1 1

EL1 CAV 11.6 68.3(23)1*1 MCHX Fixed-PSC 6*0.33 2 (100%/50%)

EL1 VAV 11.6 33.3(20)1*1 MCHX Fixed-3Phase 2*1 1

EL2 CAV 12.5 49.9(20)1*1 MCHX Fixed-3Phase 3*1.1 2 (100%/67%)

EL2 VAV 12.5 32.9(NA)1*1 MCHX Fixed-3Phase 2*1 1

EL2.5 CAV 13.2 58.0(21)1*1 MCHX Fixed-3Phase 3*1 2 (100%/67%)

EL2.5 VAV 13.2 32.9(NA)1*1 MCHX Fixed-3Phase 2*1 1

EL3 13.5 68.3(23)1*1 MCHX Fixed-PSC 6*0.33 2 (100%/50%)

EL4 14.9 58.0(21)1*1 MCHX Fixed-3Phase 3*1 2 (100%/67%)

EL5 

Maxtech 15.6 58.0(21)2*1 MCHX Fixed-3Phase 3*1 2 (100%/50%)
31

30-ton Units: Indoor Heat Exchangers and Fans

ID HX ID Fan

EL IEER Face Area (FPI) Rows Speed+Type hp

Baseline 10.6 32.1(15)4 FixedSpeed/Stage+Belt 7.5

EL1 CAV 11.6 31.4(14)4 FixedSpeed+Belt 5

EL1 VAV 11.6 32.1(15)3 VS+Belt 7.5

EL2 CAV 12.5 31.7(15)4 FixedSpeed+Belt 7.5

EL2 VAV 12.5 31.7(15)4 VS+Belt 10

EL2.5 CAV 13.2 25.5(14)5 FixedSpeed+Belt 5

EL2.5 VAV 13.2 31.3(16)6 VS+Belt 15

EL3 13.5 31.4(14)4 VS+Belt 5

EL4 14.9 25.5(14)5 VS+Belt 5

EL5 Maxtech 15.6 32.5(14)5 VS+Belt 7.5

ID fan staging: Baseline is CAV; EL3, EL4, EL5 are VAV; other ELs as 

indicated.
32

Performance correlations for field ESPs

Correlations for component power input and unit 

capacity adjusted to reflect field ESP for building 

analysis.

• ESP levels analyzed

– 0.75 and 1.25 in. wc. for ductwork, as indicated for BLAST models.

– For EL3 and above, also considered 0.2 in. wc. additional pressure drop 

for conversion curbs in replacement applications.

• Correlation adjustments

– Re-calculate indoor fan power based on the same rated full-load air flow 

at the specified ESP.

– Adjust capacity downwards to account for additional fan/motor heat 

input.

– Other performance correlation coefficients unchanged.
33

Equipment Size Trends—Conversion Curbs

DOE conducted additional review of equipment size to help 

confirm which efficiency levels require use of conversion curbs 

for replacements.

Baseline 11.4

EL1 12.9

EL2 14.0

EL2.5 14.5

EL3 14.8

EL3.5 15.8

EL4 19.9

EL5

Maxtech 21.5
34

Equipment Size Trends—Conversion Curbs

Baseline 11.2

EL1 12.4

EL2 13.2

EL2.5 13.7

EL3 14.2

EL3.5 15.0

EL4 18.5

EL5

Maxtech 20.1
35

Equipment Size Trends—Conversion Curbs

Baseline 10.6

EL1 CAV 11.6

EL2 VAV 12.5

EL2.5 13.2

EL3 13.5

EL4 14.9

EL5

Maxtech 15.5
36

Comparison of SAV and VAV

For field application of small and large SAV-rated units 

in VAV applications, the analysis currently uses 

correlations based on SAV operation.

• Some small and large units are installed with VAV.

• Analysis for the 15-ton EL3 unit shows that IEER difference for 

SAV and VAV configuration is small.

– 14.2 IEER for SAV, 14.3 IEER for VAV.

– VAV required to achieve the analyzed efficiency level at EL5 for 15-tons—

no consideration of VAV for 7.5-ton ratings.

– Some over-estimation of fan energy savings in ventilation mode possible 

at EL5 for 15-ton analysis.

• The analysis uses SAV performance correlations for applications 

that are VAV in the base-case scenario.

• This will not apply for the very large (30-ton) analysis, for which 

the indoor air options considered include only CAV and VAV.
37

Comparison of SAV and VAV

SAV (15-ton EL3)

VAV

Stage Ambient ctual % Loa Target T Net Cap Cmpr (Pc) Cond (Pcf)Indoor (Pif)Control (Pct EER Cd LF

°F Net Cap Btu/h W W W W Btu/W

3 95 100% 171,963 12,085 1,097 1,108 32 12.01

2 78.3 69.1% 78.29 118,753 7,258 1,119 414 24 13.47

75% Interpolation 13.19

1 65.3 44.8% 65.18 77,014 2,911 1,136 414 24 17.17

50% Interpolation 16.38

1 65 44.8% 65.22 77,123 2,901 1,136 414 24 17.24

25% Adjusted for Cyclic Performance 15.26 1.058 0.557

IEER 14.18

Stage Ambient ctual % Load Net Cap Cmpr (Pc) Cond (Pcf)Indoor (Pif)Control (Pct EER Cd LF

°F Net Cap Btu/h W W W W Btu/W

3 95 100% 171,963 12,085 1,097 1,108 32 12.01

2 78.3 69.1% 118,753 7,258 1,119 414 24 13.47

75% Interpolation 13.19

1 65 43.3% 74,407 2,904 1,136 209 24 17.41

50% Interpolation 16.38

1 65 43.3% 74,407 2,904 1,136 209 24 17.41

25% Adjusted for Cyclic Performance 15.95 1.055 0.578

IEER 14.27
38

Modeling of VAV (30 ton analysis)

VAV units with variable-speed compressors:

• IEER based on close match of load levels (25%, 50%, 75%) with 

the same discharge temperature as for 100% load.

• “Close match” may be +/-3% per not-yet-published versions of 

update to AHRI 340-360?

• Similar approach for multi-stage unit with many stages.

• Performance correlations for building modeling based on 

extending the 4-load-level approach to a fuller range of ambient 

temperatures.

• Potential Complications:

– Compressor capacity variation with ambient temperature leads to 

changes in discharge temperature. Modeling could consider ambienttemperature variation of compressor speed or air flow or both.

– Discharge temperature reset. 

– Both of these factors would likely increase the indoor fan power.
39

Modeling of VAV (30 ton analysis)

VAV units with single-speed compressors:

• IEER based on compressor staging, with the same discharge 

temperature as for 100% load.

• Simple approach for building modeling:

– Equipment performance correlations based on compressor staging with 

indoor air flow levels as determined for the IEER test conditions.

• Potential Complications:

– Is this appropriate for VAV units with few compressor stages, e.g. two 

stages? 

– Other complications mentioned for units with VAV compressors: 

potential variation of air flow with ambient temperature to address 

compressor capacity variation and discharge temperature reset.
40

Cost Results

• DOE estimated incremental manufacturing production costs 

(MPCs) using the manufacturing cost model based on physical 

and catalog teardowns of models on the market.

– Estimated incremental MPCs for each manufacturer individually, then 

averaged the results.

– De-coupled from energy modeling and considers the full range of 

manufacturers and equipment offerings using rated IEER values.

– Evaluated each airflow design path separately, considering only CAV or 

SAV models for EL1 and EL2 based on the path.
41

Cost Results

• In cases where the rated IEER values did not match exactly with 

proposed efficiency levels:

– Primary method was to linearly interpolate/extrapolate results (e.g., used MPCs 

for models at 12.5 IEER and 13 IEER to estimate cost at 13.2IEER by 

extrapolation).

– For efficiency levels with limited models:

• Developed incremental costs to be representative of the industry average (e.g., for EL4 

for 7.5T and 15T, DOE applied the relative percentage increase in cost for the one 

manufacturer at that level across the other manufacturers to better represent average 

labor and production factors.)

• For 30T, DOE is seeking additional information and feedback on an 

approach for developing the cost-efficiency curves:

– Insufficient models to evaluate each manufacturer individually.

– Variations in box sizes:

• Smaller cabinets that more closely resemble lower capacity designs.

• Larger cabinets that more closely resemble higher capacity designs.
42

Controls

• Controls vary by unit size and complexity. For unit capacities 

below 30 tons, we modeled the following: 

– Control boards similar to those found in residential rooftop units are 

sufficient for single-compressor, low capacity units. They may interface 

with contactors, which do the actual equipment switching.

• These systems interface with traditional 24VAC on/off thermostats and can 

control up to two compressors or compressor stages.

– VFD-controlled airflow for SAV models triggers the need for a more 

complex control system with additional sensors that provide feedback. 

• These systems are modeled to interface with a 24VAC control system and 

can also control 3+ stage compressor systems. 

• These systems may also stage outdoor fan systems, for example. 

– Variable-speed compressor systems trigger the need for an even more 

sophisticated control system to monitor refrigerant flow, temperatures, 

etc. while running a VFD for the compressor. 

• These systems typically rely on serial communications to thermostats to 

capture temperature, humidity, their rates of change, etc. 
43

Controls

• For capacities at or above 30 tons, we modeled the following: 

– Heavy-duty power management systems (i.e. banks of 3-pole circuit 

breakers for major sub-assemblies, 400VA transformer, etc.)

– Compressor current monitoring.

• Regardless of capacity, 

– All VAV units also feature the sophisticated controller.

– A separate DDC interface is added to any VAV units to interface with 

building control systems.
44

7.5-ton Units: Cost-Efficiency Curve

• “MPC Path-1” is CAV below EL3; “MPC Path-2” is SAV at all ELs above baseline. 

• DOE observed that EL3 was achieved with both SAV and VAV, depending on the manufacturer. 

Because VAV requires sophisticated controller, DOE also presented costs for this EL averaged 

across all manufacturers considering both SAV and VAV.
45

7.5-ton Units: Incremental Costs

EL IEER Total MPC

Incremental MPC 

(Single Compressor 

Baseline)

Incremental MPC 

(Dual Compressor 

Baseline)

Shipping 

Cost

Shipping 

Weight (lbs)

Baseline Single 

Compressor 11.4 $1,947.33 - - $278.57 749.4

Baseline Dual 

Compressor 11.4 $2,110.04 - - $278.57 832.5

EL1 CAV 12.9 $2,394.77 $447.44 $284.74 $278.57 907.3

EL1 SAV 12.9 $2,365.85 $418.52 $255.82 $278.57 880.3

EL2 CAV 14 $2,672.21 $724.88 $562.18 $278.57 990.1

EL2 SAV 14 $2,737.46 $790.13 $627.43 $278.57 963.7

EL2.5 14.5 $2,836.11 $888.78 $726.07 $278.57 987.6

EL3 SAV-only 14.8 $2,924.49 $977.16 $814.46 $278.57 996.3

EL3 SAV&VAV 14.8 $3,325.52 $1,378.18 $1,215.48 $278.57 996.3

EL3.5 15.8 $3,072.46 $1,125.13 $962.42 $278.57 1043.7

EL4 19.9 $3,452.52 $1,505.19 $1,342.49 $360.00 1213.0

EL5 Maxtech 21.5 $4,105.51 $2,158.18 $1,995.48 $360.00 1320.0
46

15-ton Units: Cost-Efficiency Curve
47

15-ton Units: Incremental Costs

EL IEER Total MPC

Incremental 

MPC

Total 

Shipping 

Cost

Incremental 

Shipping Cost

Shipping 

Weight (lbs)

Baseline 11.2 $4,115.95 - $360.00 - 1702.8

EL1 CAV 12.4 $4,412.72 $296.77 $360.00 $0.00 1836.0

EL1 SAV 12.4 $4,462.10 $346.15 $360.00 $0.00 1754.8

EL2 CAV 13.2 $4,610.56 $494.61 $405.00 $45.00 1924.8

EL2 SAV 13.2 $4,797.55 $681.60 $360.00 $0.00 1865.9

EL2.5 13.7 $4,974.17 $858.22 $405.00 $45.00 1947.5

EL3 14.2 $5,169.16 $1,053.21 $405.00 $45.00 1995.7

EL3.5 15 $5,289.84 $1,173.89 $405.00 $45.00 2033.1

EL4 18.5 $5,545.71 $1,429.76 $450.00 $90.00 2228.9

EL5 Maxtech 20.1 $8,080.08 $3,964.13 $450.00 $90.00 2264.3
48

30-ton Units: MPCs

• Path-1 baseline-EL2.5 is CAV, EL3-max tech is VAV; Path-2 is VAV at all ELs above baseline. 

• DOE is seeking guidance from the group on how to develop cost-efficiency curves for the two 

airflow design paths given the limited number of models and cabinet size differences. 

• DOE is seeking information from manufacturers on the following:

– Data on the percentage of shipments of small vs. large cabinets in the very large equipment class?

– Market-share by manufacturer to consider a market-share weighted average cost-curve?

• In the absence of data, DOE will develop the cost-efficiency curves with the data available.
49

Agenda

1. Introduction and Background 

2. CWAF Status and Issues

3. CUAC Engineering Analysis

4. CUAC Energy Use Analysis

5. CUAC LCC/PBP Analysis

6. Wrap-Up
50

Energy Conservation Standards Rulemaking Process

RFI NOPR Final 

Rule
51

Summary of Analysis Approach Revisions--Buildings

Issue Revised Approach Additional Input 

Required

Design 

Temperature for 

System Sizing

Revised from 95°F to 1% Cooling Dry-Bulb Design 

Temperature.

Generally reduces the number of units serving the building.

None

Load Factor (LF) for 

determining Cyclic 

Degradation

Corrected to calculate LF based on the highest stage of 

operation. 

Corrected to use CD at highest stage of operation rather 

than setting CD equal to 1.

Sensitivity analysis for treating units in a single building 

separately – i.e., not running at same load.

None

Indoor Fan Speed 

for Space-Heating

Revised from low speed to high speed. None

Indoor Fan for 

Space-Cooling

Revised from being dependent on dry-bulb temperature to 

equipment stage.

LF used to determine fan energy use in upper stages of 

operation.

None

External static 

pressure

0.75 and 1.25 in wc, as designated for BLAST model input. 

Add 0.2 in wc for EL3 and higher replacements due to 

conversion curb.

None
52

Generalized Building Sample

• LCC requires a sample of buildings to provide the additional 

inputs needed for the energy use and operating cost 

calculations.

• Single CBECS building:

• Demographic features: census division, climate, building activity, 

ownership, vintage, sample weight,...

• Building features: floorspace, number of floors, occupancy, ...

• System features: cooling equipment, heating equipment, VAV/CAV, ...

• Generalized building:

• Retain those features most relevant to CUAC energy use

• region, building activity, floorspace, vintage, VAV/CAV, ...

• One row of the LCC sample represents one CUAC unit placed 

in one of the generalized building types

• Each GBS type is weighted by total capacity (sq-ft * tons/sq-ft)

52
53

Building Characteristics

53

• Region  climate and electricity price

• Building activity  occupancy, schedule, internal loads

• Building size  electricity prices, percentage of VAV

• Vintage  envelop characteristics and internal loads 

Characteristic Number Range of Values

Region 10 9 census divisions with Pacific subdivided into 

North/South

Building Activity 7 Assembly, Education, Food Service, Health Care 

Office, Mercantile, Warehouse

Size 3 Small: < 10,000 sq ft

Medium < 100,000 sq ft

Large >= 100,000 sq ft

Vintage 4 1700-1979

1980-1999

2000-2012

2013-2019

Air System 2 CAV or VAV
54

Generalized Building Sample Input Data

• Update to CBECS 2012 for floorspace distribution in 2012

• Update to AEO2015 for estimated floorspace in 2019

• AEO projects total floorspace by activity and census division

– 2 new vintage categories, 2000-2012 and 2013-2019

– Use AEO to add new floorspace for years 2013-2019

– Subdivide Pacific census division using population estimates.

• Assume fixed distribution of building size (small, medium, large)

• Assume fixed distribution of CAV/VAV systems

• Distributed by building type and building size

• New construction cooling load adjusted using factors calculated in 

the AEO commercial demand module

• Applied to both 2000-2012 and 2013-2019 categories

54
55

Floorspace Distribution 2019

55
56

New Construction Cooling Load Correction Factors (2000-2012)

56

Census

Division Assembly Education

Food 

Sales

Food 

Service

Health 

Care Lodging

Large 

Office

Small 

Office

Mercan

tile

Other

1 0.943 0.939 0.948 1.023 0.957 0.979 0.957 0.961 1.024 0.788

2 0.866 0.589 0.914 1.005 0.941 0.959 0.891 0.911 0.929 0.852

3 0.955 0.940 0.982 1.014 0.959 1.003 0.968 0.959 0.976 0.798

4 0.903 0.885 0.945 0.989 0.943 1.006 0.943 0.929 1.013 0.830

5 0.866 0.850 0.981 0.996 0.917 0.925 0.863 0.875 0.933 0.834

6 0.841 0.726 0.814 0.995 0.929 0.896 0.862 0.826 0.887 0.846

7 0.762 0.780 0.900 0.993 0.937 0.879 0.827 0.848 0.884 0.789

8 0.890 0.894 0.958 1.009 0.973 0.933 0.925 0.900 0.933 0.745

9 0.748 0.751 0.748 1.002 0.841 0.958 0.768 0.836 0.777 0.609
57

New Construction Cooling Load Correction Factors (2003-2019)

57

Census

Division Assembly Education

Food 

Sales

Food 

Service

Health 

Care Lodging

Large 

Office

Small 

Office

Mercan

tile

Other

1 0.840 0.835 0.842 0.908 0.855 0.870 0.847 0.853 0.909 0.699

2 0.773 0.525 0.811 0.892 0.840 0.854 0.790 0.809 0.826 0.755

3 0.849 0.838 0.868 0.898 0.856 0.892 0.854 0.850 0.865 0.706

4 0.804 0.793 0.836 0.875 0.843 0.893 0.835 0.824 0.897 0.737

5 0.771 0.759 0.868 0.882 0.819 0.824 0.763 0.774 0.826 0.737

6 0.750 0.651 0.721 0.880 0.830 0.799 0.763 0.734 0.787 0.747

7 0.679 0.700 0.795 0.878 0.839 0.786 0.733 0.752 0.785 0.700

8 0.790 0.796 0.847 0.892 0.866 0.828 0.816 0.795 0.825 0.659

9 0.666 0.670 0.663 0.887 0.752 0.853 0.678 0.740 0.689 0.538
58

Mapping the “1033” to the Generalized Building Sample

• The 1033 sample is taken from CBECS1995

• All information about energy use comes from these buildings

• Create a CUAC load per ton (equivalently per unit) from the 1033 

sample by averaging with region/building type/vintage (first two 

categories)

• Assign the load to the appropriate category in the GBS

• Use the cooling load correction factors to define loads for 

vintages 2000-2012 and 2013-2019

• Screen the 1033 based on total system requirement, removing 

buildings that are too small

• Screen out buildings with > 4 stories for 7.5ton

58
59

Fan Power Calculations have changed significantly

• Using the maximum stage fan power in heating mode

• Previous approach used a linear relationship to temperature 

which underestimated fan power at high temperatures

• Introducing higher ESPs (0.75 and 1.25, with 0.2 conversion curb 

adder for all buildings at EL 3 and higher)

59
60

7.5-ton Annual Energy Use Results: NOPR vs Revised

60

EL IEER

NOPR Revised

Cooling Fan Total Cooling Fan Total

kWh/unit kWh/unit kWh/unit kWh/unit kWh/unit kWh/unit

Base 11.4 7,764 5,318 13,082 10,419 7,799 18,218 

1-CAV 12.9 6,647 4,796 11,443 9,178 8,675 17,852 

1-VAV 12.9 - - - 9,557 6,425 15,982 

2-CAV 14.0 6,401 4,235 10,636 7,427 8,306 15,733 

2-VAV 14.0 - - - 8,714 6,226 14,940 

2.5 14.5 - - - 8,082 5,027 13,109 

3 14.8 4,899 1,833 6,732 7,801 5,289 13,090 

3.5 15.8 - - - 6,728 6,981 13,709 

4 19.9 2,481 1,029 3,511 5,855 6,969 12,824 

5 21.5 4,887 4,753 9,640 
61

7.5-ton Annual Energy Use Results: NOPR vs Revised

61

Region EL IEER

NOPR Revised

Cooling Fan Total Cooling Fan Total

kWh/unit kWh/unit kWh/unit kWh/unit kWh/unit kWh/unit

Warm Base 11.4 9,300 5,216 14,516 12,103 7,663 19,766 

Warm 1-CAV 12.9 8,051 4,705 12,756 10,679 8,574 19,253 

Warm 1-VAV 12.9 - - - 11,151 5,776 16,927 

Warm 2-CAV 14.0 7,567 4,155 11,722 8,703 8,387 17,089 

Warm 2-VAV 14.0 - - - 10,174 5,780 15,954 

Warm 2.5 14.5 - - - 9,510 4,616 14,126 

Warm 3 14.8 6,193 1,911 8,104 9,195 4,868 14,063 

Warm 3.5 15.8 - - - 7,910 6,497 14,407 

Warm 4 19.9 3,559 1,062 4,621 6,898 6,154 13,052 

Warm 5 21.5 - - - 5,764 4,355 10,119 

Cool Base 11.4 6,500 5,401 11,902 8,293 7,972 16,265 

Cool 1-CAV 12.9 5,491 4,872 10,363 7,283 8,802 16,085 

Cool 1-VAV 12.9 - - - 7,545 7,245 14,789 

Cool 2-CAV 14.0 5,442 4,301 9,743 5,818 8,204 14,022 

Cool 2-VAV 14.0 - - - 6,873 6,789 13,661 

Cool 2.5 14.5 - - - 6,280 5,545 11,826 

Cool 3 14.8 3,834 1,769 5,603 6,042 5,821 11,863 

Cool 3.5 15.8 - - - 5,236 7,593 12,829 

Cool 4 19.9 1,594 1,003 2,597 4,539 7,997 12,536 

Cool 5 21.5 - - - 3,781 5,254 9,035 
62

15-ton Annual Energy Use Results: NOPR vs Revised

62

EL IEER

NOPR Revised

Cooling Fan Total Cooling Fan Total

kWh/unit kWh/unit kWh/unit kWh/unit kWh/unit kWh/unit

Base 11.2 15,005 7,845 22,850 21,721 17,952 39,673 

1-CAV 12.2/12.4 13,785 7,151 20,936 18,516 14,370 32,886 

1-VAV 12.2/12.4 - - - 18,657 11,195 29,852 

2-CAV 13.2 11,955 6,645 18,600 17,663 15,717 33,379 

2-VAV 13.2 - - - 17,270 10,308 27,578 

2.5 14.5 - - - 18,695 11,886 30,581 

3 14.2 13,212 3,324 16,536 15,894 11,801 27,695 

3.5 15.0 - - - 14,850 10,909 25,759 

4 18.4/18.5 8,916 3,463 12,379 11,884 9,833 21,717 

5 20.1 - - - 10,232 11,379 21,611 
63

Load Factor Calculations

• Suppose we have 2 15-ton units

• In a given hour, suppose the heat load is “20 tons”

• Current approach assigns each unit 10 tons of heat removal

• Load factor of 2/3

• Degradation factor of 1.043 (1.13 – 0.13*LF)

• One alternative (not necessarily more realistic)

• One unit could be fully loaded, load factor 1, degradation factor 1

• One unit removes 5 tons, load factor 1/3, degradation factor 1.087

• Energy-weighted average degradation factor is 1.029

• Currently degradation factor only applied to compressor

• Staging may contribute an additional effect

• Sensitivity analysis can determine the impact on energy use

• Should be less than a few percent

63
64

Agenda

1. Introduction and Background 

2. CWAF Status and Issues

3. CUAC Engineering Analysis

4. CUAC Energy Use Analysis

5. CUAC LCC/PBP Analysis

6. Wrap-Up
65

Energy Conservation Standards Rulemaking Process

RFI NOPR Final 

Rule
66

Summary of Analysis Approach Revision--LCC and PBP Analysis

Issue Approach Additional Input 

Requested

Design Paths Multiple design paths addressed based on system type in 

building, i.e., Constant Air Volume (CAV) buildings 

assigned CAV equipment designs and Variable Air Volume 

(VAV) buildings assigned SAV/VAV designs through EL2. 

Fraction of CAV and VAV buildings currently based solely 

on CBECS. After EL2, all buildings get SAV/VAV designs.

Manufacturer info 

on CAV/VAV

shipments to 

complement 

CBECS data. 

SAV and VAV

Costs

Additional installed costs for replacing diffusers and 

adding controls (e.g., thermostats) in CAV buildings to 

accommodate Staged Air Volume (SAV) and VAV 

equipment designs. 

Input on cost of 

diffusers and 

thermostats.

Conversion 

Curb Costs

Additional installed costs starting at EL3 for conversion 

curbs to accommodate equipment designs with large 

footprints. 

Input on 

conversion curb

cost.
67

Summary of Analysis Approach Revision--LCC and PBP Analysis

Issue Approach Additional Input 

Requested

Repair Costs Include compressor repair costs. NOPR included 

compressor repair costs only in the shipments analysis 

as a driver for repair vs. replacement decision. Because 

compressor repairs occur in base case (i.e., without new 

standards), compressor repair costs should be included. 

Compressor and non-compressor repair costs increase 

as a function of efficiency. Costs based on RS Means.

Input on cost of 

compressor and 

non-compressor 

repairs.

Equipment

Lifetime

Equipment lifetime extended due to inclusion of 

compressor repairs in base case. Equipment lifetime 

determined from shipments model based on historical 

shipments.

Input on equipment 

lifetime values.

Base Case 

Efficiency 

Distribution

Separate efficiency distributions for CAV and VAV 

buildings. For example, CAV equipment designs are not 

applied to VAV buildings.

Manufacturer info 

on CAV/VAV 

shipments and 

shipments by 

efficiency level.
68

Life-Cycle Cost (LCC) and Payback Period (PBP) Analysis

Purpose

• Provide an economic evaluation from the consumer’s perspective.

• Life-Cycle Cost (LCC) is the total consumer cost over the life of the 

equipment. 

• Payback Period (PBP) is the time required to recover the increased 

purchase price of more energy-efficient equipment through reduced 

operating costs.

Method

• Use consumer samples developed in the energy use analysis.

• Determine total installed costs for each efficiency level (EL).

• Determine first-year and equipment lifetime operating costs.

• Calculate PBP by dividing average increase in installed cost by average 

decrease in first-year operating cost.

• Calculate LCC by adding installed cost and lifetime operating costs.

• Calculate LCC savings by subtracting LCC of each EL from LCC of the EL 

that customer would purchase in the absence of a new standard.
69

• Consumer samples were based on the generalized building sample 

developed in the energy use analysis for each of the three CUAC 

equipment classes.

• Each consumer has a unique energy use and energy price.

• Other inputs (e.g. discount rates and lifetimes) are characterized by 

probability distributions.

• Monte Carlo sampling was used to create a consumer list with variable 

values for these inputs.

LCC and PBP Analysis: Consumer Sample
70

Mapping Equipment Design to CAV and VAV buildings

Efficiency 

Level

Equipment

Design

Equipment Choice Conversion Curb

Diffuser

Replacement Thermostat

CAV

Bldg

VAV

Bldg

CAV

Bldg

VAV

Bldg

CAV

Bldg

VAV

Bldg

CAV

Bldg

VAV

Bldg

0 CAV CAV n/a n/a n/a n/a n/a 1- or 2-stg Var

1

CAV CAV n/a n/a n/a n/a n/a 2-stg Var

SAV (2 IAF) n/a SAV n/a n/a n/a n/a 2-stg Var

2

CAV CAV n/a n/a n/a n/a n/a 2-stg Var

SAV (2 IAF) n/a SAV n/a n/a n/a n/a 2-stg Var

2.5 SAV (2 IAF) SAV SAV n/a n/a n/a n/a 3-stg Var

3 SAV (2 IAF) SAV SAV Yes Yes n/a n/a 3-stg Var

3.5 SAV (2 IAF) SAV SAV Yes Yes n/a n/a 2-stg Var

4 SAV (2 IAF) SAV SAV Yes Yes n/a n/a 3-stg Var

5 SAV (2 IAF) SAV SAV Yes Yes n/a n/a 2-stg Var

• 7.5-ton CUAC: Accounting for Conversion Curb and Diffuser/Thermostat replacement.
71

Mapping Equipment Design to CAV and VAV buildings

Efficiency 

Level

Equipment

Design

Equipment Choice Conversion Curb

Diffuser

Replacement Thermostat

CAV

Bldg

VAV

Bldg

CAV

Bldg

VAV

Bldg

CAV

Bldg

VAV

Bldg

CAV

Bldg

VAV

Bldg

0 CAV CAV n/a n/a n/a n/a n/a 2-stg Var

1

CAV CAV n/a n/a n/a n/a n/a 2-stg Var

SAV (2 IAF) n/a SAV n/a n/a n/a n/a 2-stg Var

2

CAV CAV n/a n/a n/a n/a n/a 2-stg Var

SAV (2 IAF) n/a SAV n/a n/a n/a n/a 2-stg Var

2.5 SAV (2 IAF) SAV SAV n/a n/a n/a n/a 2-stg Var

3 SAV (2 IAF) SAV SAV Yes Yes n/a n/a 3-stg Var

3.5 SAV (2 IAF) SAV SAV Yes Yes n/a n/a 3-stg Var

4 SAV (3 IAF) SAV SAV Yes Yes Yes + 

sensor

n/a 3-stg Var

5 VAV (2 IAF) SAV SAV Yes Yes Yes + 

DDC sensor n/a Var Var

• 15-ton CUAC: Accounting for Conversion Curb and Diffuser/Thermostat replacement.
72

LCC and PBP Analysis: Total Installed Cost (1)

• Total Installed Cost is the sum of equipment price and installation 

cost.

• Equipment price provided by Markups Analysis.

• Constant real prices used to project CUAC and CUHP equipment 

prices.

- Producer Price Index (PPI) series for “unitary air-conditioners, except heat 

pumps” spanning 1978 to 2013 was analyzed to forecast future 

equipment prices; no discernable long-term declining trend.

Cap. Design 

Path

Efficiency Levels

0 –

Single

0 –

Dual 1 2 2.5 3 3.5 4 5

7.5 ton SAV $5,970 $6,419 $6,850 $7,346 $7,640 $7,793 $8,063 $8,857 $10,027 

CAV $5,970 $6,419 $6,798 $7,463 

15 ton SAV $12,466 $13,013 $13,440 $14,110 $14,491 $14,713 $15,227 $19,897 

CAV $12,466 $13,104 $13,722 
73

LCC and PBP Analysis: Total Installed Cost (2)

• Total Installed Cost is the sum of equipment price and installation 

cost.

• Installation costs represent the labor and materials necessary to 

install the equipment

• Costs based on RS Means.

• Installation costs are assumed to increase proportionally with 

equipment weight, which increases with efficiency level. 

Cap. Design 

Path

Efficiency Levels

0 –

Single

0 –

Dual 1 2 2.5 3 3.5 4 5

7.5 ton SAV $2,476 $2,750 $2,997 $3,271 $3,263 $3,296 $3,452 $4,008 $4,361 

CAV $2,476 $2,750 $2,908 $3,184 

15 ton SAV $3,346 $3,607 $3,782 $3,827 $3,921 $3,995 $4,379 $4,449 

CAV $3,346 $3,448 $3,666 
74

LCC and PBP Analysis: Conversion Curb and T’stat Costs

• Conversion Curb installation cost represents the labor and materials 

necessary to accommodate a unit with a footprint larger than the unit 

it is replacing

• Cost based on limited input; range of $1000 to $2000 estimated.

• Because installation costs already account for increases as a function of 

efficiency, $1000 chosen as an initial estimate.

• Applied to efficiency levels 3, 3.5, 4 and 5.

• Thermostat cost represents the price to the customer of a new 

thermostat

• Costs based on prices from alpine.com and vary as a function of 

equipment staging

- 1-stage compressor and 1-stage fan: $180

- 2-stages at compressor or fan or both: $221

- 3-stages at compressor of fan or both: $290

- 4-stages/variable-speed at compressor or fan or both: $310

• Labor to install is estimated to remain constant regardless of t’stat type
75

LCC and PBP Analysis: Diffuser Replacement Costs

• Diffuser Replacement Cost represents labor and materials necessary to 

replace diffusers suitable for CAV or SAV (≥60% full airflow) systems with 

those that are suitable for SAV (<60% full airflow) and VAV systems

• Costs based primarily on Taylor Engineering and RS Means.

- Based on self-powered VAV diffusers; lower cost than subzoning with VAV boxes.

- Each diffuser costs $200-$250 more than conventional diffuser.

- Temperature sensors may be required; $150 per point / $1000 per point for DDC.

Conventional Diffuser Total with VAV Diffuser VAV Diffuser Cost per sq ft VAV Diffuser Cost per sq ton

Type of Diffuser Labor 

Hours

Wages 

per 

Hour

Mat’l Total 

Cost

Cost 

per

sq ft

Cost 

per

ton

No Temp 

Sensor

Temp 

Sensor

DDC 

Temp 

Sensor

No Temp 

Sensor

Temp 

Sensor

DDC 

Temp 

Sensor

No Temp 

Sensor

Temp 

Sensor

DDC 

Temp 

Sensor

Perforated

12x12 0.667 $74.35 $66 $116 $0.58 $223 $341 $491 $1,341 $1.70 $2.45 $6.70 $655 $943 $2,578 

18x18 0.8 $74.35 $115 $174 $0.87 $335 $399 $549 $1,399 $2.00 $2.75 $7.00 $768 $1,057 $2,691 

Rectangular

12x12 0.667 $74.35 $73 $123 $0.61 $235 $348 $498 $1,348 $1.74 $2.49 $6.74 $668 $957 $2,592 

18x18 0.889 $74.35 $128 $194 $0.97 $373 $419 $569 $1,419 $2.10 $2.85 $7.10 $806 $1,094 $2,729 

Circular

12" 0.667 $74.35 $40.50 $90 $0.45 $173 $315 $465 $1,315 $1.58 $2.33 $6.58 $606 $894 $2,529 

18" 0.889 $74.35 $124 $190 $0.95 $365 $415 $565 $1,415 $2.08 $2.83 $7.08 $798 $1,087 $2,721 

Average $0.74 $284 $1.86 $2.61 $6.86 $717 $1,005 $2,640 

Avg Difference $1.13 $1.88 $6.13 $433 $721 $2,356 
76

• Annual energy savings provided by Energy Use Analysis.

• Electric utility tariff data used to develop average and marginal electricity prices.

– Average electricity prices and marginal energy and demand prices developed for nine 

Census Divisions and California.

– Baseline energy bill determined by multiplying energy consumption by average price.

– Energy bill savings determined by multiplying energy savings by marginal energy price 

and demand reduction by demand price.

LCC and PBP Analysis: Annual Energy Cost

Region

Average Electricity

Price ¢/kwh

Marginal Demand

Price $/kW

Marginal Consumption

Price ¢/kwh

annual summer winter annual summer winter annual summer winter

New England 14.91 15.56 14.22 12.14 13.96 10.85 9.64 9.75 9.47

Mid-Atlantic 15.27 15.92 14.59 12.69 13.77 11.87 9.27 9.58 9.00

East North Central 12.36 12.59 12.00 12.54 13.25 12.00 6.28 6.36 6.18

West North Central 7.80 8.30 7.41 5.55 6.33 4.98 5.53 5.86 5.28

South Atlantic 10.16 10.10 10.12 7.94 8.17 7.79 7.03 7.00 7.02

East South Central 8.46 8.11 8.73 6.90 7.25 6.67 5.72 5.58 5.80

West South Central 7.65 8.25 6.97 3.92 4.38 3.57 5.87 6.44 5.20

Mountain 10.35 10.35 10.25 7.87 8.04 7.72 7.12 7.12 7.11

Pacific – WA,OR 6.93 7.01 6.84 2.59 2.59 2.58 5.51 5.50 5.51

Pacific – CA 16.41 17.50 15.28 6.80 9.36 4.49 12.15 12.35 11.77

US Average 11.17 11.52 10.75 8.33 9.11 7.71 7.34 7.53 7.12
77

• DOE used Annual Energy Outlook (AEO) 2015 for projections of future average 

energy prices for each census division.

LCC and PBP Analysis: Annual Energy Cost

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

2010 2015 2020 2025 2030 2035 2040 2045

cents / kWh (2013$)

Year

Electricity Price Forecasts

AEO 2015

AEO 2014

AEO 2013
78

• Maintenance costs represent the labor and materials necessary to 

maintain the equipment

– Costs based on RS Means.

– Maintenance costs do not increase with efficiency of the equipment.

– Costs are $302 annually for 7.5 ton and 15 ton units, and $414 

annually for 30 ton units

LCC and PBP Analysis: Maintenance Costs
79

• Repair costs are associated with repairing or replacing components that 

have failed.

• Non-compressor repair costs are based on RS Means and are assumed to 

scale with equipment price.

– Applied to all consumers in year 10 of the lifetime of the equipment 

(where the lifetime exceeds 10 years).

LCC and PBP Analysis: Repair Costs (1)

Cap. Design 

Path

Efficiency Levels

0 –

Single

0 –

Dual 1 2 2.5 3 3.5 4 5

7.5 ton SAV $1,606 $1,727 $1,843 $1,977 $2,056 $2,097 $2,169 $2,383 $2,698 

CAV $1,606 $1,727 $1,829 $2,008 

15 ton SAV $1,957 $2,043 $2,110 $2,215 $2,275 $2,310 $2,390 $3,124 

CAV $1,957 $2,057 $2,154 
80

• Repair costs are associated with repairing or replacing components that 

have failed.

• Compressor repair costs are based on material costs from Grainger and 

labor costs from RS Means, and are assumed to scale with equipment 

price.

– Applied to 20% of consumers, representing the portion of the population 

that chooses to repair rather than replace in the no-standards case.

– Applied to all consumers in year 10 of the lifetime of the equipment 

(where the lifetime exceeds 10 years).

LCC and PBP Analysis: Repair Costs (2)

Cap. Design 

Path

Efficiency Levels

0 –

Single

0 –

Dual 1 2 2.5 3 3.5 4 5

7.5 ton SAV $3,546 $3,812 $4,068 $4,363 $4,538 $4,629 $4,789 $5,261 $5,955 

CAV $3,546 $3,812 $4,038 $4,433 

15 ton SAV $10,741 $11,212 $11,580 $12,157 $12,485 $12,677 $13,119 $17,143 

CAV $10,741 $11,290 $11,823 
81

• ASHRAE database served as source of information for CUAC equipment 

lifetime.

– Included 215 packaged rooftop units listed as in service, with a median 

age of 16 years.

– Five units that had been replaced had a median age of 22 years. 

– Data suggest that median lifetime is longer than 15 years.

• Shipments Model calibration yielded equipment lifetimes based on a 

Weibull probability distribution.

– ≥65,000 Btu/h and <135,000 Btu/h: Mean = 21.1 years; Median = 21.0 years.

– ≥135,000 Btu/h and <240,000 Btu/h: Mean = 22.6 years; Median = 23.0 years.

– ≥240,000 Btu/h and <760,000 Btu/h: Mean = 33.7 years; Median = 34.0 years.

• NOPR analysis for all CUAC: Mean = 18.4 years; Median = 18.7 years.

– Did not account for compressor repairs in the base case.

– For ≥240,000 Btu/h and <760,000 Btu/h, effectively assumed 30+ year 

lifetime as all units were repaired after first failure.

LCC and PBP Analysis: CUAC Equipment Lifetime
82

• Used to convert streams of annual operating expenses to the year of 

purchase (i.e., 2019). 

• Estimated as the weighted average cost of capital using capital asset 

pricing model (CAPM). 

• Damodaran Online is a source of information about company debt and 

equity financing.

– Financial cost of any debt incurred to purchase equipment

– Opportunity cost of any equity to purchase equipment

• Discount rates were estimated for the types of firms on whose premise a 

CUAC or CUHP is located.

– Sectors for which discount rates were developed: Retail, Property Owners, 

Medical Services, Lodging, Food Service, Offices, Industrial, and Public

– Weighed-average real discount rate = 4.66%

LCC and PBP Analysis: Discount Rates
83

• LCC and PBP analysis typically analyzes standard levels relative to a baseline efficiency level.

– Not all consumers purchase products at baseline levels.

• Base case efficiency distributions define the percentage of products purchased at various efficiency levels.

– Consumers already purchasing products at efficiencies greater than or equal to a prospective standard level are not 

impacted by the standard. 

– Allows more accurate estimation of consumer impacts.

• EER market share data from 1999-2001 were used as a basis for the base case distribution. 

– EERs were mapped into IEERs using the same method as the Engineering Analysis.

• Historical IEER market shares and the Shipments model were used to estimate base case efficiency in the 

year of compliance (2019). 

• Separate efficiency distributions for CAV and VAV buildings.

• No new data to inform how distributions should change from NOPR.

LCC and PBP Analysis: Energy Efficiency in the Base Case

Small CUAC:

≥65,000 Btu/h and < 135,000 Btu/h

Large CUAC:

≥135,000 Btu/h and < 240,000 Btu/h

Very Large CUAC: 

≥240,000 Btu/h and

< 760,000 Btu/h

EL IEER

Market Share

IEER

Market Share

IEER

Market 

Share

NOPR NOPR

CAV

Bldg

VAV

Bldg NOPR

CAV

Bldg

VAV

Bldg

0 11.4 61% 61% n/a 11.2 78% 78% n/a 10.1 63%

1 12.9 39% 39% 61% 12.2/12.4 20% 20% 78% 11.6 24%

2 14.0 0% 0% 39% 13.2 2% 2% 20% 12.5 7%

2.5 14.5 n/a 0% 0% 13.7 n/a 0% 2% - -

3 14.8 1% 1% 0% 14.2 0% 0% 0% 13.5 4%

3.5 15.8 n/a 0% 1% 15.0 n/a 0% 0% - -

4 19.9 0% 0% 0% 18.4/18.5 0% 0% 0% 15.5 1%

5 21.5 n/a 0% 0% 20.1 n/a 0% 0% - -
84

7.5-ton LCC and PBP Results: NOPR vs Revised

EL IEER

NOPR Revised

Total 

Installed 

Cost

First Year

Operating 

Cost

Lifetime 

Operating 

Cost

Life-Cycle 

Cost

Simple 

Payback 

Period

years

Total 

Installed 

Cost

First Year

Operating 

Cost

Lifetime 

Operating 

Cost

Life-Cycle 

Cost

Simple 

Payback 

Period

years

Base 11.4 $7,689 $20,356 $28,045 - $8,773 $2,212 $31,922 $40,695 -

1 12.9 $8,024 $18,289 $26,312 $9,743 $2,108 $30,639 $40,383 9.4

2 14.0 $9,359 $17,120 $26,479 $10,543 $1,929 $28,213 $38,756 6.3

2.5 14.5 - - - - - $10,853 $1,754 $25,827 $36,680 4.5

3 14.8 $9,689 $13,051 $22,740 $11,952 $1,752 $25,838 $37,791 6.9

3.5 15.8 - - - - - $12,302 $1,774 $26,216 $38,518 8.1

4 19.9 $11,348 $9,448 $20,796 $13,640 $1,692 $25,300 $38,940 9.4

5 21.5 - - - - - $15,087 $1,413 $21,584 $36,671 7.9

EL IEER

NOPR Revised

Average LCC

Savings

Percent of 

Consumers

with Net Cost

Average LCC

Savings

Percent of 

Consumers

with Net Cost

1 12.9 $1,059 0% $318 4% 

2 14.0 $894 28% $1,401 7% 

2.5 14.5 - - $3,456 3% 

3 14.8 $4,616 0% $2,356 18% 

3.5 15.8 - - $1,634 29% 

4 19.9 $6,561 0% $1,212 41% 

5 21.5 - - $3,481 24% 
85

15-ton LCC and PBP Results: NOPR vs Revised

EL IEER

NOPR Revised

Total 

Installed 

Cost

First Year

Operating 

Cost

Lifetime 

Operating 

Cost

Life-Cycle 

Cost

Simple 

Payback 

Period

years

Total 

Installed 

Cost

First Year

Operating 

Cost

Lifetime 

Operating 

Cost

Life-Cycle 

Cost

Simple 

Payback 

Period

years

Base 11.2 $13,212 $2,703 $33,014 $46,226 - $15,772 $4,503 $68,719 $84,491

1 12.2/12.4 $14,078 $2,508 $30,622 $44,700 4.4 $16,518 $3,837 $58,955 $75,473 1.1

2 13.2 $15,695 $2,266 $27,641 $43,336 5.7 $17,199 $3,743 $57,707 $74,906 1.9

2.5 13.7 - - - - - $17,853 $3,705 $57,166 $75,019 2.6

3 14.2 $16,548 $2,101 $25,597 $42,145 5.5 $19,270 $3,449 $53,472 $72,743 3.3

3.5 15.0 - - - - - $19,560 $3,265 $50,758 $70,317 3.1

4 18.4/18.5 $17,748 $1,690 $20,563 $38,311 4.5 $29,556 $2,878 $45,144 $66,710 8.5

5 20.1 - - - - - $49,105 $2,832 $45,359 $74,196 19.9

EL IEER

NOPR Revised

Average LCC

Savings

Percent of 

Consumers

with Net Cost

Average LCC

Savings

Percent of 

Consumers

with Net Cost

1 12.2/12.4 $1,189 1% $3,000 0% 

2 13.2 $2,528 4% $3,613 29% 

2.5 13.7 - - $3,470 31% 

3 14.2 $3,713 4% $5,746 15% 

3.5 15.0 - - $8,171 7% 

4 18.4/18.5 $7,541 2% $3,789 44% 

5 20.1 - - -$15,975 71% 
86

Buildings with Economizers

Region

No Economizers Economizers Fraction with Economizers Cooling Load per cooled sq.ft.

Cooling Load Cooled Sq.Ft. Cooling Load Cooled Sq.Ft. Cooling Load Cooled Sq.Ft. No Econ Econ

New Eng 1,110,028,842 264,830,858 719,155,215 210,739,604 39% 44% 3.56 2.51

Mid Atl (NY) 3,222,433,054 603,790,868 2,660,273,338 627,972,570 45% 51% 5.43 3.26

E.N. Cntrl (MI) 2,670,937,150 600,736,951 2,907,474,997 621,701,341 52% 51% 3.94 5.37

W.N. Cntrl (MN) 1,324,865,180 306,641,067 1,239,768,258 263,844,740 48% 46% 3.81 4.12

S. Atl (FL) 8,464,003,237 1,360,942,579 2,556,504,536 480,320,250 23% 26% 5.84 5.00

E.S. Cntrl (TN) 3,978,692,146 636,817,367 904,771,508 145,532,760 19% 19% 5.51 7.09

W.S. Cntrl (TX) 6,013,150,579 971,831,121 1,875,352,662 269,052,264 24% 22% 6.71 7.54

Mntn (AZ, CO) 1,897,714,433 270,140,368 570,972,116 153,736,348 23% 36% 6.82 2.42

Pac NW 403,923,185 94,579,857 446,782,076 122,656,567 53% 56% 4.69 5.13

CA 4,044,861,009 908,578,090 1,995,781,440 526,990,181 33% 37% 4.68 3.38

Total 33,130,608,815 6,018,889,126 15,876,836,145 3,422,546,625 32% 36% 5.36 3.98

BLAST Building Sample

CBECS

Square Footage Fractions

Total Economizers >50% Pack Cool

>50% Pack Cool 

and Econ

Econ Fraction of 

Total

>50% Pack Cool 

Fraction of Total

>50% Pack Cool + 

Econ as fraction of 

>50% Pack Cool

1995 58,772,070,712 16,550,201,930 12,274,131,902 4,173,456,893 28% 21% 34%

1999 67,337,801,620 21,255,991,874 18,904,613,190 6,932,053,842 32% 28% 37%

2003 71,657,900,522 21,108,420,509 14,843,343,966 5,812,865,077 29% 21% 39%

2012 87,043,000,000 30,746,000,000 34,544,000,000 13,522,928,670* 35% 40% 39%*

CBECS

* Estimated assuming 80% of additional economized sq.ft. is >50% cooled with package AC.
87

Energy Code Adoption

Source: www.energycodes.gov/adoption/states
88

Energy Code Compliance

State Survey 

Year

Compliance 

Rate

Compliance Rate Notes Building 

Sample

Source 

California 2007 0%-56% 

Average compliance with each of 4 

components (lighting and duct related);

Each building receives score of 0, 0.5, or 1 for 

each measure

400 

records

(100 onsite)

Khawaja 

et al 2007

Minnesota 1994 50%

Percent of buildings that complied with 

lighting measures in code

38 on-site Czershin 

et al 1994

Mass. 2012 83%

On average buildings perform 17% worse than 

code; 

No building was 100% in compliance

75 on-site DNV 

KEMA et al 

2012

New York 2011

36% Percent of buildings passing 26 on-site Harper et 

al 2012

85%

The proportion of all energy code 

requirements, averaged

across all sampled buildings that are in 

compliance
89

Agenda

1. Introduction and Background 

2. CWAF Status and Issues

3. CUAC Engineering Analysis

4. CUAC Energy Use Analysis

5. CUAC LCC/PBP Analysis

6. Wrap-Up
90

Next Steps

• Revisions to proposed schedule based on today’s progress?

• Other issues to consider during the next Working Group meeting?