Residential Water Heater

Efficiency Standards:

Life-Cycle Cost Analysis

Jim Lutz

Lawrence Berkeley National Laboratory

11/9/98 Analysis1 GLC0

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Role in Standards Process

* Economic Impact on Consumers

* Input:

- Engineering Analysis

- GAMA

- LBNL Water Heater Database

* Output:

- Selection of Trial Standards Levels

- Manufacturer Impact Analysis

- National Energy Savings Forecast

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Overview of LCC

Analysis Methodology

* Spreadsheet Tools - by fuel type

* 5 major modules w/ supporting data sheets

* Variability and uncertainty of inputs

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Implementation

* Excel spreadsheet with Crystal Ball add-in

* Inputs are probability distributions

* 10,000 calculations

* Values selected from input distributions

* Results as frequency distributions

* Different tank sizes, household sizes,

temperatures, etc.

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Variability and Uncertainty

* Variability:

- value depends on something else

- e.g. average daily hot water use depends on

number of people in household

* Uncertainty:

- value is not well known

- e.g. thermostat setpoint has large range and is

not well characterized

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Types of Distributions

* triangular

* custom distribution

* discrete distribution

* normal distribution

* RECS data

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Schematic of LCC Analysis

LCC &

Payback

Equipment Operating

Cost Cost

Energy Use

Hot Water

Use

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Hot Water Use

* Use depends on:

- number and age of people

- air and water temperatures

- tank size, appliances, adults at home

* from Gilbert Associates, EPRI EA-4006

* extended by LBNL to cover

- no clothes washers or dishwashers

- senior only households in multi-family buildings

- not paying for hot water

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Hot Water Use

Sampled RECS Data

* actual households

- people / climate / fuel type / energy price

- e.g. no pre-schoolers living by themselves

* weighted by EIA to represent population

* temperatures

- air from NOAA

- inlet water = annual air +2°F

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Hot Water Use

Setpoint Temperature

200

180

LL

^o,~~~ ~~Ttank= 134.1 +0.55 *(58-Tin) 13

160

1)

| 14 0 ...... -. . :

., '- * -- -- - --... -*

u 120 |-r* - . . ... -- 

I)-<

80 - ---- I - -

50 55 60 65 70 75 80 85

Cold Water Temperature (deg F)

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Hot Water Use

Average Hot Water Use

Households Average Daily Hot

Water Use

(gallons/day)

with Electric Water Heaters 44.3

with Gas-fired Water Heaters 48.9

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Hot Water Use

Daily Hot Water Use

Daily Hot Water Use Daily Hot Water Use

Households with Gas-fired Water Heaters Households with Electric Water Heaters

(gal/day) (gal/day)

3000 _- ... aH --. _...,,^ 100% 2000 ...... ........ 100%

2500u n 80% > 1500 °80% 0 0 2000 >" 80 I 

O O O O OO O O60% | 60%

g 1000 E E 500 ,20% Q 2 500 0 20% U. 500 20%

0 0% 0 0%

0000000000 OOO00000 000

c) (D O N U)LO O0 N N N C0 -t (0 c0 0 N 00 o O

Gal/Day Gal/Day

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Energy Use

Consumption

vol.den.Cp. tank T intank 24 UA. T tank T amb) Q in--' . ...... .... 4.UA.T tank T amb? RE Pon

* Vol - from Hot Water Use

* RE, UA, Pon from simulation models

* Tin - average outdoor air temp + 2 °F

* Ttank - thermostat setpoint temperature

* Tamb - temperature air around water heater

* den, Cp - properties of water

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Energy Use

Water Heater Location

Location Percent Assumed Air

Temperature

Unheated 20.9% Average of

Basement outdoor & 72°F

Heated 26.0% 72°F

Basement

Garage 24.7% Outdoor + 5 °F

House 28.3% 72°F

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Energy Use

Electric Water Heater

Design Options Average Average Energy

Electricity Use Savings

(kWh/yr) (Btu/day)

0 Analytic Baseline 3503

1 0 + Heat Traps 3408 884

2 1 +2" Jacket Insulation 3362 1312

3 1 + 2.5" Jacket Insulation 3318 1726

4 3 + Plastic Tank 3276 2121

5 3 + Insulated Tank Bottom 3296 1936

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Energy Use

Gas-fired Water Heater

Design Options Average Energy Use Average Energy

(MCF/yr) (kWh/yr) Savings (Btu/day)

0 Analytic Baseline 22.32

1 0 + Heat Traps 21.72 1671

2 1 + 2" Jacket Insulation 20.58 4886

3 1 + 2.5" Jacket Insulation 20.34 5567

4 3 + Side Arm Heater w/llD 17.37 23 13719

5 2 + Improved Flue Baffle 20.04 6422

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Operating Cost

OprCost= AnnualEnergyUse · FutureEnergyPrice + MaintCost

FutureEnergyPrice = EnergyPrice 98 · EnergyIncrRatio

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Operating Cost

10 , Electricity Price Scenarios

9

0) - - ---

7

' 6

( , AEO 1998

« ___...GRI 1998

~5 -wx GRI extended

_ High Growth

. - Low Growth

1995 2000 2005 2010 2015 2020

year

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Operating Cost

Natural Gas Price Scenarios

7

o0

°° 6 °- 6

GRI 1998

K GRI extended

_ _ High Growth

_ - Low Growth

4 - -

1995 2000 2005 2010 2015 2020

year

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Operating Cost

Electric Water Heater

Design Options Average Annual Average Savings

Operating Costs from Baseline

0 Analytic Baseline $292.93

1 0 + Heat Traps $285.05 $7.88

2 1 + 2" Jacket Insulation $281.22 $1 1.71

3 1 + 2.5" Jacket Insulation $277.55 $15.38

4 3 + Plastic Tank $274.01 $18.92

5 3 + Insulated Tank Bottom $275.66 $17.27

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Operating Cost

Gas-fired Water Heater

Design Options Average Annual Average Savings

Operating Costs from Baseline

0 Analytic Baseline $159.36

1 0 + Heat Traps $155.12 $4.24

2 1 + 2" Jacket Insulation $147.00 $12.36

3 1 + 2.5" Jacket Insulation $145.28 $14.08

4 3 + Side Arm Heater w/llD $126.25 $33.11

5 2 + Improved Flue Baffle $143.10 $16.26

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Equipment Cost

EquipCost = MfrCost · Markup · ( 1 + SalesTax) + TotInstCost

* Manufacturer Cost

* Markup

* Sales Tax

* Total Installation Cost

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Equipment Cost

Manufacturer Cost

* baseline model costs from GAMA

- 40 gallon gas-fired water heater

- 50 gallon electric water heater

- HCFC-141b foam insulation

* design option costs from GAMA

- Heat Traps, 2" Jacket Insulation, Insulated

Tank Bottom for electric water heaters

- Heat Traps, 2" Jacket Insulation, IID, Improved

Flue Baffle for gas-fired water heaters

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Equipment Cost

Manufacturer Cost (cont'd)

* scaled for HFC-245fa foam insulation

* scaled for other rated volumes

- 30, 40, 65 and 80 gallon sizes for electric;

- 30, 50 and 75 gallon sizes for gas units

* 2.5" jacket insulation costs scaled up from 2"

jacket insulation.

* plastic tank, side arm heater from other sources.

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Equipment Cost

LBNL Water Heater Database

* nearly 80 retail & wholesale distributors

- nation wide

- retail prices for all models sold

- installation and delivery, removal, permits, parts

- sales tax

* manufacturer product literature (dimensions,

features)

* GAMA directory (efficiency, ratings)

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Equipment Cost

Retail Price

Retail Price Retail Price

Electric Water Heaters Gas-fired Water Heaters

$600 $600

$567

$500 - - -$479 $500 - - -.- - -...

, ... „„ $429 4 .$452

$400 | $357 $380 $400 . .. $

8 p357 ! $357

Q $300 -- $290- $277- $ -- - $275 $300 -

! $260 $256

$200 $ $1- 1 60 $179 - - $200 - - - .$195

i~~~ ~~~~~$158 g.$12~$146 150 $133 $100 - 112 $116 $128 $100 - $11833

$0 l I $0- I 

30 gal 40 gal 50 gal 65 gal 80 gal 30 gal 40 gal 50 gal 75 gal

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Equipment Cost

Markup

* Markup = Retail Price / Manufacturer Cost

* Inputs are distributions

* Varies by size

* Retail Price

- 5 year warranties

- no extra features

* Manufacturer Cost

- existing baseline model

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Equipment Cost

Installation Cost

InstallatInstallation Cost

Electric Water HeatersGas-fired ater Heaters

$3$300 --- 

$250 $25258 $258 $258 __$250 .. $258 $258 _ $258

r $200 . .- $175 $209_ $ - $200 1

200 210C 21$50 

$150 , $165 $167 $1 65 c $150 $163 $160 57 $159 ~$150 $16 - $1 $150

~0)~~~ ~$145 $100- $100.. - $100_

$65 $65 $65 $50.$ $65 $6565

$0 $0- - -- -

30 gal 40 gal 50 gal 65 gal 80 gal 30 gal 40 gal 50 gal 75 gal

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Equipment Cost

Extra Installation Costs

* Electricity for Side Arm Heater

* Type-B vent connector for Improve Flue

Baffle

* Burner tube extension for increased

insulation on oil-fired

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Equipment Costs

Electric Water Heater

Design Options Average Average Total

Manufacturer Installed Costs

Costs

0 Analytic Baseline $121.13 $345.09

1 0 + Heat Traps $127.81 $355.58

2 1 + 2" Jacket Insulation $148.43 $388.35

3 1 + 2.5" Jacket Insulation $163.97 $413.08

4 3 + Plastic Tank $191.90 $456.98

5 3 + Insulated Tank Bottom $196.86 $464.68

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Equipment Costs

Gas-fired Water Heater

Design Options Average Average Total

Manufacturing Installed Costs

Costs

0 Analytic Baseline $175.56 $385.76

1 0 + Heat Traps $177.94 $388.86

2 1 + 2" Jacket Insulation $194.50 $411.47

3 1 + 2.5" Jacket Insulation $205.93 $427.04

4 3 + Side Arm Heater w/llD $314.05 $602.15

5 2 + Improved Flue Baffle $201.67 $530.50

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Life-Cycle Cost & Payback

Equations

Lifetime

Life e OprCost option.year LCOCEquipCost option + X _-_-

year= (1 1 Drate)year

EquipCost ption- EquipCost baseline

Payback optio-----n- ---

OprCost baseline- OprCost option

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Life-Cycle Cost & Payback

Equations

LCC EquiLCost(option) L OprCost(option, year) LCC= EquipCost(option) + , ----- year (1 + Drate)year

. EquipCost(option) - EquipCost(baseline) Payback(option) =

OprCost(baseline) - OprCost(option)

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Life-Cycle Cost & Payback

Discount Rate

Cash & savings Drae

mo gage

_~ 2~~~~~~~~~Credit cards

I.

0.00%/ 3.75% 7.50% 11.25% 15.00%/

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Life-Cycle Cost & Payback

Electric Water Heater Lifetimes

Ufetime

. =

4.00 7.75 11.50 15.25 19.00

Appliance Magazine, Sept 1998

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Life-Cycle Cost and Payback

Electric Water Heaters

Design Options Fraction of Average Median

Population LCC Payback

Benefitting Savings (years)

1 Heat Traps 94.9% $54.11 1.07

2 1 + 2" Jacket Insulation 83.9% $52.93 3.49

3 1 + 2.5" Jacket Insulation 79.9% $58.67 4.14

4 3 + Plastic Tank 68.6% $43.55 5.76

5 3+ InsulatedTankBottom 59.3% $22.51 6.79

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Life-Cycle Cost and Payback

Sensitivity Analysis Electric Water Heaters

Discount rate ': ':110.39

Total Installed Cost 0.34 2.5" Jacket Insulation

Lifetime -0.28

Operating Cost -0.22 ;.

Baseline

Operating Cost -0.19

2.5" Jacket Insulation

Total Installed Cost

Baseline

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

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Life-Cycle Cost and Payback

Gas-fired Water Heaters

Design Options Fraction of Average Median

Population LCC Payback

Benefitting Savings (years)

1 Heat Traps 95.5% $26.51 0.70

2 1 + 2" Jacket Insulation 97.9% $60.56 1.87

3 1 + 2.5" Jacket Insulation 93.8% $57.01 2.62

4 3 + Side Arm Heater w/llD 54.9% $14.70 6.25

5 3 + Improved Flue Baffle 21.6% ($31.27) 9.35

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Life-Cycle Cost and Payback

Sensitivity Analysis Gas-fired Water Heaters

Lifetime -0.50 -Li :?11 -i:

Discount Rate 1111 ; 10.45

Operating Cost -0.27

Baseline

Operating Cost25

2" Jacket Insulation -0

Total Installed Cost

2" Jacket Insulation

Total Installed Cost 0.10

Baseline

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1

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Request for Stakeholder Comments

* water heater lifetimes

* manufacturing costs, retail prices, and installation

costs

* manufacturer cost to retail price markups

* insulation characteristics and costs

* projected fuel price scenarios

· uncertainty on EF, RE, and UA for design options

* inlet water temperatures

* thermostat setpoint temperatures

* hot water use models

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