5-D-i

APPENDIX 5-D. ROOM AIR CONDITIONER ENGINEERING DATA 

TABLE OF CONTENTS 

5-D.1 INTRODUCTION .....................................................................................................5-D-1

5-D.2 MANUFACTURING COST MODELING DETAILS ...........................................5-D-1

5-D.3 ENERGY MODELING DETAILS ........................................................................5-D-12

5-D.4 DESCRIPTION OF SUPPORTING ANALYSES ................................................5-D-20

5-D.4.1 Room Air Conditioner Airflow Modeling..............................................................5-D-20

5-D.4.2 Room Air Conditioner Motor Analysis ..................................................................5-D-21

LIST OF TABLES 

Table 5-D.2.1 Incremental Cost Detail for 5,000 Btu/h Louvered, No Reverse Cycle 

Room Air Conditioner (Product Class 1) – Final Rule Analysis ............... 5-D-3

Table 5-D.2.2 Incremental Cost Detail for 8,000 Btu/h Louvered, No Reverse Cycle 

Room Air Conditioner (Product Class 3) – Final Rule Analysis ............... 5-D-5

Table 5-D.2.3 Incremental Cost Detail for 12000 Btu/h Louvered, No Reverse Cycle 

Room Air Conditioner (Product Class 3) – Final Rule Analysis ............... 5-D-6

Table 5-D.2.4 Incremental Cost Detail for 24000 Btu/h Louvered, No Reverse Cycle 

Room Air Conditioner (Product Class 5A) – Final Rule Analysis ............ 5-D-7

Table 5-D.2.5 Incremental Cost Detail for 28000 Btu/h Louvered, No Reverse Cycle 

Room Air Conditioner (Product Class 5B) – Final Rule Analysis............. 5-D-8

Table 5-D.2.6 Incremental Cost Detail for 8000 Btu/h Non-Louvered, No Reverse 

Cycle Room Air Conditioner (Product Class 8A) – Final Rule Analysis 5-D-10

Table 5-D.2.7 Incremental Cost Detail for 12000 Btu/h Non-Louvered, No Reverse 

Cycle Room Air Conditioner (Product Class 8B) – Final Rule Analysis 5-D-11

Table 5-D.3.1 MarkN Results for 5000 Btu/h Louvered, No Reverse Cycle Room Air 

Conditioner (Product Class 1) – Final Rule Analysis ............................... 5-D-13

Table 5-D.3.2 MarkN Results for 8000 Btu/h Louvered, No Reverse Cycle Room Air 

Conditioner (Product Class 3) – Final Rule Analysis ............................... 5-D-14

Table 5-D.3.3 MarkN Results for 12000 Btu/h Louvered, No Reverse Cycle Room 

Air Conditioner (Product Class 3) – Final Rule Analysis......................... 5-D-15

Table 5-D.3.4 MarkN Results for 24000 Btu/h Louvered, No Reverse Cycle Room 

Air Conditioner (Product Class 5A) – Final Rule Analysis...................... 5-D-16

Table 5-D.3.5 MarkN Results for 28000 Btu/h Louvered, No Reverse Cycle Room 

Air Conditioner (Product Class 5B) – Final Rule Analysis ...................... 5-D-17

Table 5-D.3.6 MarkN Results for 8000 Btu/h Non-Louvered, No Reverse Cycle 

Room Air Conditioner (Product Class 8A) – Final Rule Analysis .......... 5-D-18

Table 5-D.3.7 MarkN Results for 12000 Btu/h Non-Louvered, No Reverse Cycle 

Room Air Conditioner (Product Class 8B) – Final Rule Analysis........... 5-D-19

Table 5-D.4.1 Components Modeled to Calculate Room Air Conditioner Airflow ....... 5-D-21
5-D-ii

LIST OF FIGURES 

Figure 5-D.4.1 Motor Incremental Cost Steps .................................................................... 5-D-22

Figure 5-D.4.2 Motor Shaft Output Ratings by Capacity for Different Product Classes . 5-D-23

Figure 5-D.4.3 Motor Pricing Increase with Weight Increase ........................................... 5-D-24

Figure 5-D.4.4 Weight-Current Curves for room air conditioner PSC motors, grouped 

by shaft output ............................................................................................. 5-D-25

Figure 5-D.4.5 Cost of Increased Efficiency for Different Motor Output Ratings ........... 5-D-26

Figure 5-D.4.6 Brushless DC Motor Cost Curve by Shaft Output Rating ........................ 5-D-27
5-D-1

APPENDIX 5-D. ENGINEERING DATA 

5-D.1 INTRODUCTION 

Chapter 5 presents incremental cost curves describing costs to attain each analyzed 

efficiency level for the six products analyzed in detail. The U.S. Department of Energy (DOE) 

developed the curves using design option analysis based on energy use modeling using the 

MarkN program and manufacturing cost modeling. 

The tables in section 5-D.2 show the costs associated which each of the design 

configurations analyzed. The tables identify the design options associated with each design 

configuration and show the key elements comprising the cost impacts, including materials, labor, 

overhead, and depreciation. The tables also present total manufacturing production cost (MPC), 

total manufacturer sales price (MSP), and shipping cost associated with each design 

configuration. These costs represent the costs from the final rule analysis. 

 

 Details of the energy modeling are presented in section 5-D.3. Tables in this section 

identify for each analyzed design configuration the MarkN input file name, the compressor data 

file name, the MarkN key program output (energy efficiency ratio (EER) and capacity), standby 

energy use, and integrated efficiency (combined energy efficiency ratio (CEER)). These tables 

represent the analysis from the final rule analysis. 

Details of two aspects of the engineering analysis are presented in section 5-D.4. Section 

5-D.4.1 describes the airflow analysis that DOE used to account for changes in the airflow 

system, including changes to fans and heat exchangers. Section 5-D.4.2 describes the data 

collection and analysis used to develop the incremental cost estimates associated with increasing 

motor efficiency, both with higher-efficiency permanent split capacitor (PSC) motors and with 

brushless direct current (BLDC) motors. 

5-D.2 MANUFACTURING COST MODELING DETAILS 

The tables in this section itemize the results of the manufacturing cost analysis. The 

tables identify for each of the analyzed products the analyzed design configurations and their 

associated EER and CEER. The successive design configurations represent baseline designs with 

increasing numbers of design options. The total and incremental costs associated with each of the 

design configurations are presented in the tables as well, with separate identification of the key 

cost elements: materials, labor, overhead, depreciation, and shipping cost. The incremental 

manufacturing costs represent increases in MPC. The tables also show total MPC and MSC 

calculated for each design configuration. Chapter 5 describes the conversion of this data into 

incremental costs for specified efficiency levels (rather than by design configuration). The
5-D-2

efficiency level format of the data is used in the downstream analyses (i.e., life-cycle cost (LCC), 

national impact analysis (NIA), etc.) 
5-D-3

Table 5-D.2.1 Incremental Cost Detail for 5,000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 

1) – Final Rule Analysis 

Design Configuration 

Description EER IEER

Incremental Costs (MPC) Total Cost

Material Labor OH Depreciation Increase Cumulative 

Increase MPC MSP* Shipping

R-410A Baseline 8.94 8.79 - - - - - - $ 146.63 $ 184.76 $3.86

1 Add Subcooler 9.18 9.02 $0.57 $0.25 $0.10 $0.02 $0.80 $0.80 $ 147.43 $ 185.77 $3.86

2 Increase Evap Circuits 9.37 9.20 $0.75 - - - $0.75 $1.55 $ 148.18 $ 186.71 $3.86

3 Increase Compressor 

 Efficiency 9.72 9.54 $1.80 - - - $1.80 $3.35 $ 149.98 $ 188.98 $3.86

4 Stand-by Reduction 9.72 9.63 $0.75 - - - $0.75 $4.10 $ 150.73 $ 189.92 $3.86

5 Increase Evap Width 9.89 9.80 $0.65 $0.21 $1.31 $0.00 $2.17 $6.27 $ 152.90 $ 192.66 $3.86

6 Increase Chassis to 

 Medium Size 10.59 10.48 $6.74 $1.06 -$0.31 $0.01 $7.50 $13.77 $ 160.40 $ 202.10 $5.72

7 Increase Chassis to 

 Large Size 10.80 10.69 $2.67 -$0.46 $3.14 $0.01 $5.36 $19.13 $ 165.76 $ 208.86 $8.39

8 Increase Condenser

 Tube Rows 11.23 11.12 $5.58 $1.17 $0.09 $0.00 $6.85 $25.98 $ 172.61 $ 217.49 $8.39

9 Increase PSC 

 Efficiency 11.49 11.37 $8.11 - - - $8.11 $34.09 $ 180.72 $ 227.71 $8.39

10 Increase Fin 

 Thickness 11.51 11.38 $1.49 - - - $1.49 $35.58 $ 182.21 $ 229.59 $8.39

11 DC Brushless Motor 11.80 11.67 $43.50 - - - $43.50 $79.08 $ 225.71 $ 284.40 $8.39

*MSP is equal to MPC times the manufacturer markup of 1.26. 
5-D-4

(1) Add subcooler with 0.25 inches (in) outer diameter (OD), 24.25 in. length, and condensate temperature of 95o F

(2) Increase total refrigerant circuits in evaporator from 1 circuit to 2 circuits 

(3) Improve rotary R-410A compressor efficiency to 10.0 EER 

(4) Change Main Control Board to a Switching Power Supply.

(5) Increase evaporator width by 2 in. by redesigning the unit’s user interface placement.

(6) Increase Baseline Chassis Size by: Width 3 in., Height 0.75 in., Depth 2 in.

(7) Increase Baseline Chassis Size by: Width 4.2 in., Height 1.9 in., Depth 5.7 in.

(8) Convert Condenser to 3-tube row heat exchangers from 2-tube rows

(9) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor 

(10) Increase evaporator fin thickness from 0.005 in to 0.006 in. 

(11) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-5

Table 5-D.2.2 Incremental Cost Detail for 8,000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 

3) – Final Rule Analysis 

Design Option Step EER IEER

Incremental Costs Total Cost

Material Labor OH Depreciation Increase Cumulative 

Increase MPC MSP Shipping

R-410A Baseline 9.30 9.19 - - - - - - $179.60 $226.30 $6.32

1 Add Subcooler 9.60 9.50 $0.81 $0.00 $0.00 $0.00 $0.81 $0.81 $180.41 $227.32 $6.32

2 Increase Evap 

 Width 9.76 9.65 $0.88 $0.31 $0.00 $0.00 $1.20 $2.01 $181.61 $228.83 $6.32

3 Increase Compre. 

 Efficiency 10.17 10.05 $3.60 - - - $3.60 $5.61 $185.21 $233.36 $6.32

4 Stand-by Reduction 10.17 10.11 $11.36 - - - $0.75 $6.36 $185.96 $234.31 $6.32

5 Increase Chassis to

Medium Size 10.87 10.80 $8.27 $1.00 $0.46 $0.00 $9.73 $16.09 $195.69 $246.57 $9.58

6 Increase PSC

Efficiency 11.49 11.41 $13.70 - - - $13.70 $29.79 $209.39 $263.83 $9.58

7 Increase Chassis to

Large Size 11.84 11.76 $10.74 $0.97 $1.56 $0.04 $13.32 $43.11 $222.71 $280.61 $14.63

8 DC Brushless Motor 12.05 11.96 $63.14 - - - $63.14 $106.25 $285.85 $360.17 $14.63

(1) Add subcooler with 0.25 in. OD, 24.25 in. length, and condensate temperature of 95o F 

(2) Increase evaporator width by 3 in. by redesigning the unit’s user interface placement

(3) Improve rotary R-410A compressor efficiency to 10.0 EER

(4) Change Main Control Board to a Switching Power Supply.

(5) Increase baseline chassis size by: Width 0.81 in., Height 3.13 in., Depth 2.5 in. 

(6) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(7) Increase baseline chassis size by: Width 4 in., Height 3.13 in., Depth 8.1 in. 

(8) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor
5-D-6

Table 5-D.2.3 Incremental Cost Detail for 12000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 

3) – Final Rule Analysis 

Design Option Step EER IEER

Incremental Costs Total Cost

Material Labor OH Depreciation Increase Cumulative 

Increase MPC MSP Shipping

R-410A Baseline 9.76 9.68 - - - - - - $ 211.36 $ 266.31 $10.33

1 Add Subcooler 10.20 10.12 $0.75 $0.36 $0.14 $0.00 $1.25 $1.25 $ 212.61 $ 267.89 $10.33

2 Increase Compressor 

 Efficiency 11.05 10.95 $9.03 - - - $9.03 $10.28 $ 221.64 $ 279.27 $10.33

3 Standby Reduction 11.05 11.00 $0.75 $0.75 $11.03 $ 222.39 $ 280.21 $10.33

4 Increase PSC Efficiency 11.54 11.49 $18.00 - - - $18.00 $29.03 $ 240.39 $ 302.89 $10.33

5 Increase Evaporator Tube 

 Rows 11.66 11.60 $3.37 $0.92 $0.11 $0.00 $4.40 $33.43 $ 244.79 $ 308.43 $10.33

6 Increase Chassis Size to 

 Medium Size 11.97 11.92 $9.49 $1.11 $1.79 $0.01 $12.41 $45.83 $ 257.19 $ 324.06 $15.30

7 Increase Chassis Size to 

 Large Size 12.27 12.21 $10.65 $0.73 $2.27 $0.73 $13.65 $59.49 $ 270.85 $ 341.27 $20.37

8 DC Brushless Motor 12.44 12.38 $73.26 - - - $73.26 $132.75 $ 344.11 $ 433.58 $20.37

(1) Add subcooler with 0.315 in. OD, 32 in. length, and condensate temperature of 95o F 

(2) Improve rotary R-410A compressor efficiency to 10.0 EER

(3) Change Main Control Board to a Switching Power Supply.

(4) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(5) Increase number of evaporator tube rows from 3 rows to 4 rows

(6) Increase baseline chassis size by: Width 4.5 in., Height 1.125 in., Depth 2.3 in.

(7) Increase baseline chassis size by: Width 7 in., Height 1.125 in., Depth 7.2 in.

(8) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor
5-D-7

Table 5-D.2.4 Incremental Cost Detail for 24000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 

5A) – Final Rule Analysis 

Design Option Step EER IEER

Incremental Costs Total Cost

Material Labor OH Depreciation Increase Cumulative 

Increase MPC MSP Shipping

R-410A Baseline 7.87 7.84 - - - - - - $ 336.81 $ 424.38 $23.10

1 Add Subcooler 8.17 8.14 $1.61 $0.00 $0.00 $0.00 $1.61 $1.61 $ 338.42 $ 426.41 $23.10

2 Increase Chassis size 

to Medium Size 8.98 8.95 $11.31 $0.57 $0.81 $0.01 $12.70 $14.31 $ 351.13 $ 442.42 $27.22

3 Increase Condenser 

 Tube Rows 9.42 9.38 $8.28 $1.57 $0.94 $0.01 $10.80 $25.12 $ 361.93 $ 456.03 $27.22

4 Stand-by Reduction 9.42 9.40 $0.75 - - - $0.75 $25.87 $ 362.68 $ 456.98 $27.22

5 Increase Compressor

Efficiency 9.68 9.66 $15.00 - - - $15.00 $40.87 $ 377.68 $ 475.88 $27.22

6 Increase PSC 

Efficiency 10.05 10.03 $44.25 - - - $44.25 $85.12 $ 421.93 $ 531.63 $27.22

7 DC Brushless Motor 10.18 10.15 $126.33 - - - $126.33 $211.45 $ 548.26 $ 690.81 $27.22

(1) Add subcooler with 0.282 in OD, 63 in. length, and condensate temperature of 95o F 

(2) Increase baseline chassis size by: Width 1.75 in., Height 0.25 in., Depth 2.53 in.

(3) Increase number of condenser tube rows from 3 rows to 4 rows

(4) Change Main Control Board to a Switching Power Supply.

(5) Improve rotary R-410A compressor efficiency to 10.3 EER 

(6) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(7) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-8

Table 5-D.2.5 Incremental Cost Detail for 28000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 

5B) – Final Rule Analysis 

Design Option Step EER IEER

Incremental Costs Total Cost

Material Labor OH Depreciation Increase Cumulative 

Increase MPC MSP Shipping

R-410A Baseline 7.48 7.46 - - - - - - $366.81 $462.18 $23.10

1 Add Subcooler 7.74 7.72 $1.61 $0.00 $0.00 $0.00 $1.61 $1.61 $368.42 $464.21 $23.10

2 Increase Chassis size 

to Medium Size 8.29 8.26 $11.31 $0.57 $0.81 $0.01 $12.70 $14.31 $381.13 $480.22 $27.22

3 Increase Chassis size 

to Large Size 9.05 9.03 $24.51 $2.85 $6.81 $0.02 $34.18 $48.50 $415.31 $523.29 $36.46

4 Stand-by Reduction 9.05 9.04 $0.75 - - - $0.75 $49.25 $416.06 $524.24 $36.46

5 Increase Compressor

Efficiency 9.37 9.36 $16.50 - - - $16.50 $65.75 $432.56 $545.03 $36.46

6 Increase Condenser 

Tube Rows 9.46 9.44 $14.48 $2.04 $0.00 $0.01 $16.53 $82.28 $449.09 $565.86 $36.46

7 Increase PSC 

Efficiency 9.73 9.71 $44.25 - - - $44.25 $126.53 $493.34 $621.61 $36.46

8 DC Brushless Motor 9.81 9.80 $126.33 - - - $126.33 $252.86 $619.67 $780.79 $36.46
5-D-9

(1) Add subcooler with 0.282 in OD, 63 in. length, and condensate temperature of 95o F 

(2) Increase baseline chassis size by: Width 1.75 in., Height 0.25 in., Depth 2.53 in.

(3) Increase baseline chassis size by: Width 3.81 in., Height 4.69 in., Depth 2.53 in.

(4) Change Main Control Board to a Switching Power Supply.

(5) Improve rotary R-410A compressor efficiency to 10.3 EER

(6) Increase number of condenser tube rows from 3 rows to 4 rows

(7) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(8) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-10

Table 5-D.2.6 Incremental Cost Detail for 8000 Btu/h Non-Louvered, No Reverse Cycle Room Air Conditioner (Product 

Class 8A) – Final Rule Analysis 

Design Option Step EER IEER

Incremental Costs Total Cost

Material Labor OH Depreciation Increase Cumulative 

Increase MPC MSP Shipping

R-410A Baseline 8.43 8.34 - - - - - - $ 210.70 $ 265.49 $12.26

1 Increase Evap Width 9.44 9.34 $4.74 $0.43 $0.00 $0.01 $5.17 $5.17 $ 215.88 $ 272.01 $12.26

2 Add Subcooler 9.59 9.48 $0.80 $0.00 $0.00 $0.00 $0.80 $5.97 $ 216.68 $ 273.01 $12.26

3 Improve Compressor 

Efficiency 9.78 9.66 $1.65 - - - $1.65 $7.62 $ 218.33 $ 275.09 $12.26

4 Stand-by Reduction 9.78 9.72 $0.75 - - - $0.75 $8.37 $ 219.08 $ 276.04 $12.26

5 Increase PSC 

Efficiency 10.26 10.20 $14.68 - - - $14.68 $23.05 $ 233.76 $ 294.53 $12.26

6 DC Brushless Motor 10.42 10.35 $65.77 - - - $65.77 $88.82 $ 299.53 $ 377.40 $12.26

(1) Increase evaporator width by 4 inches by redesigning the unit’s user interface placement.

(2) Add subcooler with 0.25 in. OD, 24.25 in. length, and condensate temperature of 95o F

(3) Improve rotary R-410A compressor efficiency to 10.0 EER

(4) Change Main Control Board to a Switching Power Supply

(5) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(6) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-11

Incremental Cost Detail for 12000 Btu/h Non-Louvered, No Reverse Cycle Room Air Conditioner (Product Class 8B) – Final 

Rule Analysis 

Design Option Step EER IEER

Incremental Costs Total Cost

Material Labor OH Depreciation Increase Cumulative 

Increase MPC MSP Shipping

R-410A Baseline 8.37 8.32 - - - - - - $ 236.54 $ 298.04 $12.26

1 Add Subcooler 8.57 8.51 $0.68 $0.36 $0.14 $0.00 $1.18 $1.18 $ 237.72 $ 299.53 $12.26

2 Improve Compressor 

Efficiency 9.09 9.03 $6.30 - - - $6.30 $7.48 $ 244.02 $ 307.47 $12.26

3 Increase Evap width 9.59 9.52 $7.61 $1.14 $0.20 $0.01 $8.95 $16.43 $ 252.97 $ 318.74 $12.26

4 Stand-by Reduction 9.59 9.55 $0.75 - - - $0.75 $17.18 $ 253.72 $ 319.69 $12.26

5 Increase PSC 

Efficiency 9.94 9.90 $13.70 - - - $13.70 $30.88 $ 267.42 $ 336.95 $12.26

6 DC Brushless Motor 10.06 10.02 $63.23 - - - $63.23 $94.11 $ 330.65 $ 416.62 $12.26

(1) Add subcooler with 0.315 in. OD, 32 in. length, and condensate temperature of 95o F

(2) Improve rotary R-410A compressor efficiency to 10.0 EER

(3) Increase evaporator width by 6 inches by redesigning the unit’s user interface placement.

(4) Change Main Control Board to a Switching Power Supply

(5) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor. 

(6) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor
5-D-12

5-D.3 ENERGY MODELING DETAILS 

The tables in this section identify the analyzed design configurations for the analyzed 

products. For each design configuration, the tables present the key MarkN outputs (capacity and 

EER), the standby energy use, the IEER, and the MarkN input and compressor files used in the 

analysis. The MarkN program, a MarkN user manual, and the input and compressor files will be 

made available on the website for this rulemaking.
5-D-13

Table 5-D.3.1 MarkN Results for 5000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 1) – Final 

Rule Analysis 

Design Configuration 

Description MarkN Input Filename Compressor Map(EER, Capacity)

MarkN Outputs Stand-by 

Power IEER

EER Capacity

R-410A Baseline In_PC1_Baseline_R410A.dat 9.7 EER 4.6 kBtu/h 8.94 4,624 1.4 8.79

1 Add Subcooler In_PC1_Step1.dat 9.7 EER 4.6 kBtu/h 9.18 4,689 1.4 9.02

2 Increase Evap Circuits In_PC1_Step2.dat 9.7 EER 4.6 kBtu/h 9.37 4,834 1.4 9.20

3 Increase Compressor 

 Efficiency In_PC1_Step3.dat 10 EER 4.6 kBtu/h 9.72 4,842 1.4 9.54

4 Stand-by Reduction In_PC1_Step4.dat 10 EER 4.6 kBtu/h - - 0.7 9.63

5 Increase Evap Width In_PC1_Step5.dat 10 EER 4.6 kBtu/h 9.89 4,934 0.7 9.80

6 Increase Chassis to 

 Medium Size In_PC1_Step6.dat 10 EER 4.6 kBtu/h 10.59 5,066 0.7 10.48

7 Increase Chassis to 

 Large Size In_PC1_Step7.dat 10 EER 4.6 kBtu/h 10.80 5,215 0.7 10.69

8 Increase Condenser

 Tube Rows In_PC1_Step8.dat 10 EER 4.6 kBtu/h 11.23 5,324 0.7 11.12

9 Increase PSC 

 Efficiency In_PC1_Step9.dat 10 EER 4.6 kBtu/h 11.49 5,325 0.7 11.37

10 Increase Fin 

 Thickness In_PC1_Step10.dat 10 EER 4.6 kBtu/h 11.51 5,338 0.7 11.38

11 DC Brushless Motor In_PC1_Step11.dat 10 EER 4.6 kBtu/h 11.80 5,339 0.7 11.67

(1) Add subcooler with 0.25 inches (in) outer diameter (OD), 24.25 in. length, and condensate temperature of 95o F

(2) Increase total refrigerant circuits in evaporator from 1 circuit to 2 circuits 

(3) Improve rotary R-410A compressor efficiency to 10.0 EER 

(4) Change Main Control Board to a Switching Power Supply.

(5) Increase evaporator width by 2 in. by redesigning the unit’s user interface placement.

(6) Increase Baseline Chassis Size by: Width 3 in., Height 0.75 in., Depth 2 in.

(7) Increase Baseline Chassis Size by: Width 4.2 in., Height 1.9 in., Depth 5.7 in.

(8) Convert Condenser to 3-tube row heat exchangers from 2-tube rows

(9) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor 

(10) Increase evaporator fin thickness from 0.005 in to 0.006 in. 

(11) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-14

Table 5-D.3.2 MarkN Results for 8000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 3) – Final 

Rule Analysis 

Design Option Step MarkN Filename Compressor Map

(EER, Capacity)

MarkN Outputs Stand-by 

Power IEER

EER Capacity

R-410A Baseline In_PC3_12k_Baseline_R410A.dat 9.39 EER 7.6 kBtu/h 9.30 7,688 1.4 9.19

1 Add Subcooler In_PC3_8k_Step1.dat 9.39 EER 7.6 kBtu/h 9.60 7,816 1.4 9.50

2 Increase Evap 

 Width In_PC3_8k_Step2.dat 9.39 EER 7.6 kBtu/h 9.76 8,001 1.4 9.65

3 Increase Compre. 

 Efficiency In_PC3_8k_Step3.dat 10 EER 7.6 kBtu/h 10.17 8,005 1.4 10.05

4 Stand-by Reduction In_PC3_8k_Step4.dat 10 EER 7.6 kBtu/h - - 0.7 10.11

5 Increase Chassis to

Medium Size In_PC3_8k_Step5.dat 10 EER 7.6 kBtu/h 10.87 8,425 0.7 10.80

6 Increase PSC

Efficiency In_PC3_8k_Step6.dat 10 EER 7.6 kBtu/h 11.49 8,431 0.7 11.41

7 Increase Chassis to

Large Size In_PC3_8k_Step7.dat 10 EER 7.6 kBtu/h 11.84 8,633 0.7 11.76

8 DC Brushless Motor In_PC3_8k_Step8.dat 10 EER 7.6 kBtu/h 12.05 8,635 0.7 11.96

(1) Add subcooler with 0.25 in. OD, 24.25 in. length, and condensate temperature of 95o F 

(2) Increase evaporator width by 3 in. by redesigning the unit’s user interface placement

(3) Improve rotary R-410A compressor efficiency to 10.0 EER

(4) Change Main Control Board to a Switching Power Supply.

(5) Increase baseline chassis size by: Width 0.81 in., Height 3.13 in., Depth 2.5 in. 

(6) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(7) Increase baseline chassis size by: Width 4 in., Height 3.13 in., Depth 8.1 in. 

(8) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor
5-D-15

Table 5-D.3.3 MarkN Results for 12000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 3) – 

Final Rule Analysis 

Design Option Step MarkN Filename Compressor Map

(EER, Capacity)

MarkN Outputs Stand-by 

Power IEER

EER Capacity

R-410A Baseline In_PC3_12k_Baseline_R410A.dat 9.14 EER 11.3 kBtu/h 9.76 12,607 1.4 9.68

1 Add Subcooler In_PC3_12k_Step1.dat 9.14 EER 11.3 kBtu/h 10.20 12,913 1.4 10.12

2 Increase Compressor 

 Efficiency In_PC3_12k_Step2.dat 10 EER 10.9 kBtu/h 11.05 12,928 1.4 10.95

3 Standby Reduction In_PC3_12k_Step3.dat 10 EER 10.9 kBtu/h 11.05 - 0.7 11.00

4 Increase PSC Efficiency In_PC3_12k_Step4.dat 10 EER 10.9 kBtu/h 11.54 12,935 0.7 11.49

5 Increase Evaporator Tube 

 Rows In_PC3_12k_Step5.dat 10 EER 10.9 kBtu/h 11.66 13,206 0.7 11.60

6 Increase Chassis Size to 

 Medium Size In_PC3_12k_Step6.dat 10 EER 10.9 kBtu/h 11.97 13,607 0.7 11.92

7 Increase Chassis Size to 

 Large Size In_PC3_12k_Step7.dat 10 EER 10.9 kBtu/h 12.27 13,850 0.7 12.21

8 DC Brushless Motor In_PC3_12k_Step8.dat 10 EER 10.9 kBtu/h 12.44 13,854 0.7 12.38

(1) Add subcooler with 0.315 in. OD, 32 in. length, and condensate temperature of 95o F 

(2) Improve rotary R-410A compressor efficiency to 10.0 EER

(3) Change Main Control Board to a Switching Power Supply.

(4) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(5) Increase number of evaporator tube rows from 3 rows to 4 rows

(6) Increase baseline chassis size by: Width 4.5 in., Height 1.125 in., Depth 2.3 in.

(7) Increase baseline chassis size by: Width 7 in., Height 1.125 in., Depth 7.2 in.

(8) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor
5-D-16

Table 5-D.3.4 MarkN Results for 24000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 5A) – 

Final Rule Analysis 

Design Option Step MarkN Filename Compressor Map

(EER, Capacity)

MarkN Outputs Stand-by

Power IEER

EER Capacity

R-410A Baseline In_PC5A_Baseline_R410A.dat 9.79 EER 24.1 kBtu/h 7.87 22,477 1.4 7.84

1 Add Subcooler In_PC5A_Step1.dat 9.79 EER 24.1 kBtu/h 8.17 23,007 1.4 8.14

2 Increase Chassis size to 

Medium Size In_PC5A_Step2.dat 10.0 EER 23.1 kBtu/h 8.98 22,998 1.4 8.95

3 Increase Condenser 

 Tube Rows In_PC5A_Step3.dat 10.0 EER 23.1 kBtu/h 9.42 23,725 1.4 9.38

4 Stand-by Reduction In_PC5A_Step4.dat 10.0 EER 23.1 kBtu/h - - 0.7 9.40

5 Increase Compressor

Efficiency In_PC5A_Step5.dat 10.3 EER 23.1 kBtu/h 9.68 23,740 0.7 9.66

6 Increase PSC Efficiency In_PC5A_Step6.dat 10.3 EER 23.1 kBtu/h 10.05 23,766 0.7 10.03

7 DC Brushless Motor In_PC5A_Step7.dat 10.3 EER 23.1 kBtu/h 10.18 23,775 0.7 10.15

(1) Add subcooler with 0.282 in OD, 63 in. length, and condensate temperature of 95o F 

(2) Increase baseline chassis size by: Width 1.75 in., Height 0.25 in., Depth 2.53 in.

(3) Increase number of condenser tube rows from 3 rows to 4 rows

(4) Change Main Control Board to a Switching Power Supply.

(5) Improve rotary R-410A compressor efficiency to 10.3 EER 

(6) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(7) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-17

Table 5-D.3.5 MarkN Results for 28000 Btu/h Louvered, No Reverse Cycle Room Air Conditioner (Product Class 5B) – 

Final Rule Analysis 

Design Option Step MarkN Filename Compressor Map

(EER, Capacity)

MarkN Outputs Stand-by 

Power IEER

EER Capacity

R-410A Baseline In_PC5B

_Baseline_R410A.dat 9.79 EER 27.1 kBtu/h 7.48 27,326 1.4 7.46

1 Add Subcooler In_PC5B _Step1.dat 9.79 EER 27.1 kBtu/h 7.74 27,963 1.4 7.72

2 Increase Chassis size to 

Medium Size In_PC5B _Step2.dat 10.0 EER 27.1 kBtu/h 8.29 28,024 1.4 8.26

3 Increase Chassis size to Large

Size In_PC5B _Step3.dat 10.0 EER 27.1 kBtu/h 9.05 27,400 1.4 9.03

4 Stand-by Reduction In_PC5B _Step4.dat 10.0 EER 27.1 kBtu/h - - 0.7 9.04

5 Increase Compressor

Efficiency In_PC5B _Step5.dat 10.3 EER 27.1 kBtu/h 9.37 27,424 0.7 9.36

6 Increase Condenser Tube 

Rows In_PC5B _Step6.dat 10.3 EER 27.1 kBtu/h 9.46 27,647 0.7 9.44

7 Increase PSC Efficiency In_PC5B _Step7.dat 10.3 EER 27.1 kBtu/h 9.73 27,662 0.7 9.71

8 DC Brushless Motor In_PC5B_Step7.dat 10.3 EER 27.1 kBtu/h 9.81 27,666 0.7 9.80

(1) Add subcooler with 0.282 in OD, 63 in. length, and condensate temperature of 95o F 

(2) Increase baseline chassis size by: Width 1.75 in., Height 0.25 in., Depth 2.53 in.

(3) Increase baseline chassis size by: Width 3.81 in., Height 4.69 in., Depth 2.53 in.

(4) Change Main Control Board to a Switching Power Supply.

(5) Improve rotary R-410A compressor efficiency to 10.3 EER

(6) Increase number of condenser tube rows from 3 rows to 4 rows

(7) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(8) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-18

Table 5-D.3.6 MarkN Results for 8000 Btu/h Non-Louvered, No Reverse Cycle Room Air Conditioner (Product Class 8A) – 

Final Rule Analysis 

Design Option Step MarkN Filename Compressor Map

(EER, Capacity)

MarkN Outputs Stand-by 

Power IEER

EER Capacity

R-410A Baseline In_PC8A_8k_Baseline_R410A.dat 9.78 EER 7.2 kBtu/h 8.43 7,968 1.4 8.34

1 Increase Evap Width In_PC8A _8k_Step1.dat 9.78 EER 7.2 kBtu/h 9.44 8,275 1.4 9.34

2 Add Subcooler In_PC8A _8k_Step2.dat 9.78 EER 7.2 kBtu/h 9.59 8,348 1.4 9.48

3 Improve Compressor 

Efficiency In_PC8A_8k_Step3.dat 10 EER 7.2 kBtu/h 9.78 8,352 0.7 9.66

4 Stand-by Reduction In_PC8A_8k_Step4.dat 10 EER 7.2 kBtu/h - - 0.7 9.72

5 Increase PSC Efficiency In_PC8A_8k_Step5.dat 10 EER 7.2 kBtu/h 10.26 8,360 0.7 10.20

6 DC Brushless Motor In_PC8A_8k_Step6.dat 10 EER 7.2 kBtu/h 10.42 8,362 0.7 10.35

(1) Increase evaporator width by 4 inches by redesigning the unit’s user interface placement.

(2) Add subcooler with 0.25 in. OD, 24.25 in. length, and condensate temperature of 95o F

(3) Improve rotary R-410A compressor efficiency to 10.0 EER

(4) Change Main Control Board to a Switching Power Supply

(5) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor.

(6) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor 
5-D-19

Table 5-D.3.7 MarkN Results for 12000 Btu/h Non-Louvered, No Reverse Cycle Room Air Conditioner (Product Class 8B) 

– Final Rule Analysis 

Design Option Step MarkN Filename Compressor Map

(EER, Capacity)

MarkN Outputs Stand-by 

Power IEER

EER Capacity

R-410A Baseline In_PC8B_Baseline_R410A.dat 9.03 EER 11.5 kBtu/h 8.37 11,869 1.4 8.32

1 Add Subcooler In_PC8B_Step1.dat 9.03 EER 11.5 kBtu/h 8.57 12,037 1.4 8.51

2 Improve Compressor 

Efficiency In_PC8B_Step2.dat 10 EER 11.5 kBtu/h 9.09 12,068 1.4 9.03

3 Increase Evap width In_PC8B_Step3.dat 10 EER 11.1 kBtu/h 9.59 12,233 1.4 9.52

4 Stand-by Reduction In_PC8B_Step4.dat 10 EER 11.1 kBtu/h - - 0.7 9.55

5 Increase PSC Efficiency In_PC8B_Step5.dat 10 EER 11.1 kBtu/h 9.94 12,247 0.7 9.90

6 DC Brushless Motor In_PC8B_Step6.dat 10 EER 11.1 kBtu/h 10.06 12,252 0.7 10.02

(1) Add subcooler with 0.315 in. OD, 32 in. length, and condensate temperature of 95o F

(2) Improve rotary R-410A compressor efficiency to 10.0 EER

(3) Increase evaporator width by 6 inches by redesigning the unit’s user interface placement.

(4) Change Main Control Board to a Switching Power Supply

(5) Replace 50 percent efficiency PSC Motor with 70 percent efficiency PSC Motor. 

(6) Replace PSC Motor with an 80 percent efficiency Brushless DC Motor
5-D-20

5-D.4 DESCRIPTION OF SUPPORTING ANALYSES 

This section presents additional description of two aspects of the engineering analysis for room 

air conditioners:

Airflow modeling 

Motor pricing analysis 

5-D.4.1 Room Air Conditioner Airflow Modeling 

 DOE introduced the room air conditioner airflow modelling analysis during the 

preliminary analysi phase of the rulemaking, and continued the use of this analysis (developed 

during the preliminary analysis phase) to support the energy modelling analysis performed 

during the final rule analysis. DOE did not receive comments on the airflow modeling analysis 

from stakeholders during the stakeholder comment period. 

 Many factors influence the airflow characteristics of a room air conditioner. The flow 

passages, heat exchangers, motor and fans all influence the airflow behavior within the room air 

conditioner. The MarkN model treats the heat exchanger dimensions, airflows, and motor power 

as separate, decoupled inputs, so the effect of physical changes in the airflow system on the 

airflow and motor power must be calculated separately from the model. DOE conducted an 

airflow calculation for each distinct airside design configuration. 

 DOE calculated the system airflow using an iterative approach with the following steps. 

1. Select an airflow rate 

2. Calculate fan or blower pressure rise 

3. Calculate heat exchanger pressure drops using MarkN 

4. Calculate other system pressure drops using spreadsheet calculation. 

5. Add pressure drops and compare to fan or blower pressure rise. 

a. If fan pressure rise is higher than total pressure drop, increase is airflow rate and 

return to step 2 

b. If fan pressure rise is lower than total pressure drop, reduce airflow rate and return 

to step 2 

c. If fan pressure rise and total pressure drop are equal within reasonable tolerance, 

airflow calculation is complete. 

 The airflow modeling was based on calculating the pressure drops for the separate 

components of the room air conditioner and the pressure rise associated with the condenser fan 

or the evaporator blower. The approaches for calculating the pressure characteristics of the key 

component are listed in Table 5-D.4.1 below. 
5-D-21

Table 5-D.4.1 Components Modeled to Calculate Room Air Conditioner Airflow 

Component Pressure Drop Value or Calculation 

Method

Sources

Evaporator Blower Total Pressure Curve, adjusted using Fan 

Laws to match observed baseline unit 

performance.

Comair Rotron Fan Company Ltd

2008 ASHRAE Handbook:

HVAC Systems and Equipment

Condenser Fan Static Pressure Curve, adjusted using Fan 

Laws to match observed baseline unit 

performance.

Sofasco International

2008 ASHRAE Handbook:

HVAC Systems and Equipment

Filter 0.25 inches of water Filter vendors

Grilles and Louvers Loss coefficient times velocity pressure 2005 ASHRAE Handbook: Fundamentals

Ducts and Transitions Loss coefficient times velocity pressure 2005 ASHRAE Handbook: Fundamentals

Inflow to Condenser

(transition from fan 

outlet to condenser)

50 percent of Condenser Pressure Drop Estimate

Heat Exchangers MarkN Outputs MarkN Model

Fan performance curves provided a relationship between fan static pressure rise and 

airflow delivered by the fan. DOE obtained fan performance curves for fans similar in size and 

geometry to those used in the teardown units. The fan performance curves were adjusted as 

needed to match the sizes, rotational speed, and performance of the modeled room air 

conditioner fans using the fan laws. 

 On the evaporator side, DOE accounted for the airside pressure losses of the evaporator, 

the entry and exit grilles, the filter, and the impeller exit transition. On the condenser side, DOE 

accounted for the pressure losses of the condenser, the airflow path from the louvers to the fan 

inlet, and the fan exit plenum geometry. 

The evaporator and condenser pressure drops were calculated by the MarkN model based on 

assumed airflow rate. 

5-D.4.2 Room Air Conditioner Motor Analysis 

 DOE introduced the room air conditioner motor analysis during the preliminary analysi 

phase of the rulemaking, and continued the use of the analysis (developed during the preliminary 

analysis phase) to support the manufacturing cost modelling analysis performed during the final 

rule analysis. DOE did not receive comments on the motoranalysis from stakeholders during the 

stakeholder comment period. 

 Through examination of the teardown units and interviews with room air conditioner 

manufacturers, DOE determined that PSC motors are the primary motor technology used in room 
5-D-22

air conditioners to power the fan and blower assemblies. DOE examined improvement in motor 

efficiency, including higher efficiency PSC motors and brushless DC motors as design options 

for improving the energy-efficiency of the room air conditioners. 

For all of the teardown units, DOE measured the power consumption of the motor at the 

available fan speeds. In accordance with the current test procedure, DOE used the data for the 

highest fan setting in its energy models, by using the energy consumption of each fan as a model 

input. Changes in the technology of the fan motor from design options are expressed in the 

model through changes in the fan motor energy consumption. 

 Figure 5-D.4.1 below shows the steps taken to develop the incremental costs for the PSC 

motor efficiency increases. DOE researched motor characteristics and prices and established a 

room air conditioner motor database. DOE developed separate correlations for price and 

efficiency as functions of motor weight and extended this analysis to develop a relationship for 

incremental costs for increases in efficiency for PSC motors.

Figure 5-D.4.1 Motor Incremental Cost Steps 

Teardown Unit Motor Sizes

The costs associated with increasing efficiency varied by motor shaft output rating. DOE 

examined the motor shaft output ratings associated with each of the different product classes, and 

used the baseline PSC shaft output rating as the basis of its efficiency analysis. Figure 5-D.4.2 

shows the shaft output power of the motors that were examined during the reverse engineering 

work, identified by product class and room air conditioner efficiency level (baseline or high). 
5-D-23

Figure 5-D.4.2 Motor Shaft Output Ratings by Capacity for 

Different Product Classes 

Motor Efficiencies 

 DOE obtained PSC motor efficiency data from discussions with motor vendors, review of 

motor catalogs, and discussions with room air conditioner manufacturers. Most PSC motors 

found in room air conditioners have a full-load efficiency between 45 percent and 60 percent. 

High efficiency PSC motors can reach up to 70 percent efficiency. DOE selected an efficiency of 

50 percent as the baseline for the room air conditioner PSC motors, and an efficiency of 70 

percent for high efficiency PSC motors. 

Cost as a Function of Weight 

 The DOE examined motor prices for a range of power ratings from a variety of motor 

vendors. DOE examined the correlation of motor prices with weights, incoming electrical 

current, incoming electrical voltage and shaft power for both single-shafted and double-shafted

HVAC PSC motors. 

DOE noted that, across motors of similar shaft output, motor frame size, and voltage, 

motor weight consistently increases as the efficiency increases. DOE found a strong correlation 

between motor pricing and motor weight across all motor data, and used a subset of this data to 

establish a basis for pricing PSC efficiency improvements. DOE established a statistically 

significant correlation between motor price and motor weight using data from two motor 
5-D-24

vendors, for motors with rated shaft output up to 0.25 horsepower (186.5 Watts (W)). Figure 5-

D.4.3 below shows the motor data used to establish this relationship. 

The correlation establishes the increased cost of a motor per increase in weight, for PSC 

motors within the range of established room air conditioner motors. It was established as 

statistically significant through statistical t-tests and DOE used the ratio of cost per weight 

increase to help calculate the cost of increasing the motor efficiency by a given amount. 

Figure 5-D.4.3 Motor Pricing Increase with Weight Increase 

Efficiency as a Function of Weight 

 Available motor data did not generally included efficiency. However, full-load current 

data was available for most motor entries. Current is an indicator of efficiency, assuming that 

power factor does not change significantly among motors that are compared. The relationships 

between current and motor weight for a range of applicable motor sizes is illustrated in Figure 5-

D.4.4 below. These relationships were developed from the available motor data. 
5-D-25

Figure 5-D.4.4 Weight-Current Curves for room air conditioner 

PSC motors, grouped by shaft output 

Cost as Function of Efficiency

DOE combined the cost/weight and the current/weight relationships to develop a 

relationship for the cost of increasing motor efficiency from 50 percent to 70 percent as a 

function of shaft output power. DOE determined the incremental cost for this efficiency increase 

for the shaft output power levels of interest using the equation below. 

The curve shown in Figure 5-D.4.5 below illustrates the resulting cost increase as a 

function of shaft power. This relationship was developed for shaft power up to roughly 100W. 

The high end of the relationship was extrapolated linearly to 200W to represent the cost of a high 

efficiency PSC motor for a product class 5 product. DOE expects that the linear extrapolation is 

conservative, since the curve’s slope decreases as shaft power increases. 
5-D-26

Figure 5-D.4.5 Cost of Increased Efficiency for Different Motor 

Output Ratings 

Brushless DC Motors

 BLDC motors are a more efficient alternative to PSC motors, and are already in use in 

products such as in PTACs. BLDC motors provide the same output power as PSC motors at 

higher efficiencies. DOE obtained BLDC motor efficiency data from discussions with motor 

vendors, review of motor catalogs, and discussions with room air conditioner manufacturers. 

Typical BLDC motors have efficiencies between 70 percent and 90 percent. However, in 

searching for replacement motors for room air conditioners, DOE found that the average 

efficiency of these motors is approximately 80 percent; motors with 90 percent efficiency are not 

very common. DOE selected a BLDC motor efficiency of 80 percent for the analysis. 

DOE searched motor catalogs and contacted motor vendors to develop a database of 

BLDC motor characteristics. Using this data, DOE developed a representative relationship for 

the cost premium of BLDC motors as a function of shaft power. This is shown in Figure 5-D.4.6. 
5-D-27

Figure 5-D.4.6 Brushless DC Motor Cost Curve by Shaft Output 

Rating