1

Analysis of Cost and Savings Values for Revised Energy Star

Dishwasher Specifications

June 6, 2006

2

Issue Summary

• EPACT 2005 required EPA to update minimum Efficiency Requirements for Energy Star Dishwashers– Existing = EF- 58– New = EF- 65– New Requirements Effective – January 1, 2007

• Existing deemed savings and cost based on EF – 52 baseline

3

Analytical Approach

• Data Source – Retail Price– Oregon Residential Tax Credit Data for 2004 & 2005

• Retail Prices paid - (including “in store” rebates/discounts)

• EF (cycles/kWh)

• Water Factor (gals/cycle)

– Energy Star data on qualifying models

• Data Source – Energy Savings– Use DOE Test Procedure

– Use FTC Energy Guide Model Listings to Estimate Base Case

4

Oregon Residential Energy Tax Credit Data

• 2004 Tax Year• Retail Price data on 10,199 units

• Minimum EF – 58

• Some units have water factor data

• 2005 Tax Year• Retail Price Data on 6,924 units

• Minimum EF – 62

• All units have water factor data

5

DOE Test Procedure

• Defines 215 cycles/year as “average use”• Requires test of machine with and without “soil

sensor” controls• Weights test results by fraction of time

consumer adopts sensor controls– 5% Heavy sensor use– 33% Medium sensor use– 62% Light sensor use

6

Proposed Savings Assumptions

• Energy UseBase Case FTC Energy Guide Label for 2004 “average”

= 371 kWh/yr

= EF 58

Energy Star Use

= 331 kWh/yr

= EF 65

• Savings = 40 kWh/yr (w/electric water heating)

7

Consolidated Retail Price Data from Oregon Tax Credit Data Base

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0.58 0.62 0.66 0.71 0.77 0.85 1.11Energy Factor

Num

ber

of U

nits

8

Retail Price vs Energy Efficiency

$0

$200

$400

$600

$800

$1,000

$1,200

$1,400

$1,600

0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95

Energy Factor

Ret

ail P

rice

(20

05$)

Min Retail Price Average Retail Price

9

Average Retail Price vs Energy Efficiency

R2 = 0.41

$0

$200

$400

$600

$800

$1,000

$1,200

$1,400

$1,600

0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95

Energy Factor

Ret

ail P

rice

(20

05$)

Average Retail Price Poly. (Average Retail Price)

10

Minimum Retail Price vs Energy Efficiency

R2 = 0.80

$0

$100

$200

$300

$400

$500

$600

$700

$800

$900

0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95

Energy Factor

Ret

ail P

rice

(20

05$)

Min Retail Price Poly. (Min Retail Price)

Is There Really An Incremental Retail Cost?

$0

$200

$400

$600

$800

$1,000

$1,200

0.58 0.59 0.60 0.61 0.62 0.63 0.64 0.65 0.66 0.67 0.68

Average Retail Price Minimum Retail Price 1st Std Dev Below 1st Std Dev Above

12

So What Should We Assume for Incremental Cost of EF 65 vs EF 58

• Alt 1 - Use 3rd order polynomial curve fit to minimum retail price vs efficiency data

Incremental Price = $25 (2005$)

• Alt 2 – Use 3rd order polynomial curve fit to average retail price

vs efficiency data Incremental Price = $201 (2005$)

• Alt 3 – Use Average Difference in Retail PriceEF 58 Retail Price is $132 more than EF 65

• Alt 4 – Use Minimum Difference in Retail PriceEF58 Retail Price is $34 more than EF 65

13

Allocation of Savings

• For Dishwashers using water heated with electricity Dishwasher EF = cycles/kWh– 1/EF = kWh/cycle

• e.g., 215 cycles/year / 371 kWh/yr = EF 58

• Machines with the same EF can have differing shares of water use and “machine” (i.e., motor, pump, drying) electricity use– This means lowering hot water is not the only way to

increase electricity savings

14

Reduced Hot Water Use Increases Energy Factor

R2 = 0.50

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95Energy Factor

Wat

er U

se (

gals

/cyc

le)

. . .But May Not Reduce Electricity Use for Dishwashers Using Gas Water Heating

Energy Factor

0.58 0.65 0.68 0.93

Machine Energy Use (kWh/cycle) 0.347 0.523 0.459 0.504

Hot Water Use - Electric DHW (kWh/cycle) 1.38 1.02 1.01 0.57

Hot Water Use - Gas DHW (MMBtu/cycle) 0.0063 0.0046 0.0046 0.0026

Hot Water Use (gals/cycle) 8.2 6.04 6.02 3.4

Total Electricity Use w/Electric DHW (kWh/cycle)

1.72 1.54 1.47 1.08

Total Electricity Use w/Gas DHW (kWh/cycle) 0.347 0.523 0.459 0.504

kWh Savings/cycle - Electric DHW 0.19 0.25 0.65

kWh Savings/cycle - Gas DHW -0.18 -0.11 -0.16

MMBtu Savings/cycle - Gas DHW 0.0016 0.0017 0.0037

16

So What Should We Assume About the Allocation of Efficiency

• Only hot water use reduction– OR Tax Credit Data shows EF 65 uses 6.04 gal cycle

vs 8.2 for the EF models

• Assume motor and pump use declines in same proportion as hot water use– 50/50 split in energy reduction eliminates negative

electricity savings for dishwashers supplied by gas water heaters

– Problem: No data to support this

17

Proposal

• No statistical evidence to support retail price difference (EF 64 – EF 67 appears to be a “sweet spot”)– Use curve fit to minimum cost – EF58>EF65 = $25

– Test sensitivity of B/C Ratio with $0 incremental cost

• Data suggest that hot water reduction is primary method of achieving higher EF (e.g., “sensor controlled” wash)– Use average water use data from actual models in OR Tax

Credit Data Base• EF 58 = 8.2 gal/cycle EF 65 = 6.04 gal/cycle

Results Assuming EF 65 Incremental Cost of $25

Measure Incremental Cost

Total Electricity Savings (kWh/yr)

Gas Savings (Therms/yr)

Water Savings (gals/yr)

TRC B/C Ratio

EF65 - Electric Water Heater $25 40 0 463 1.3

EF65 - Gas Water Heater $25 -38 3.55 463 0.7

EF68 - Electric Water Heater $79 94 0 468 0.69

EF65 - Any Water Heater $25 12 1.28 463 0.67

EF68 - Any Water Heater $79 26 1.3 468 0.28

EF93 - Electric Water Heater $500 234 0 1,032 0.26

Any EF - Any Water Heater $112 25 1.54 557 0.22

EF68 - Gas Water Heater $79 -62 3.58 468 0.19

EF93 - Any Water Heater $500 77 2.86 1,032 0.11

EF93 - Gas Water Heater $500 -96 7.9 1,032 0.11

Results Assuming EF 65 Incremental Cost of $0

Measure Incremental Cost

Total Electricity Savings (kWh/yr)

Gas Savings (Therms/yr)

Water Savings (gals/yr)

TRC B/C Ratio

EF65 - Electric Water Heater $25 40 0 463 32.18

EF65 - Any Water Heater $25 12 1.28 463 16.61

EF65 - Gas Water Heater $25 -38 3.55 463 1.76

EF68 - Electric Water Heater $79 94 0 468 0.69

EF68 - Any Water Heater $79 26 1.3 468 0.28

EF93 - Electric Water Heater $500 234 0 1,032 0.26

Any EF - Any Water Heater $112 25 1.54 557 0.25

EF68 - Gas Water Heater $79 -62 3.58 468 0.19

EF93 - Any Water Heater $500 77 2.86 1,032 0.11

EF93 - Gas Water Heater $500 -96 7.9 1,032 0.11

20

($200)

$0

$200

$400

$600

$800

$1,000

$1,200

IncrementalCost

Gas Savings(Therms/yr)

TRC B/CRatio

EF65 - Electric WaterHeater

EF65 - Any Water Heater

EF65 - Gas Water Heater

EF68 - Electric WaterHeater

EF68 - Any Water Heater

EF93 - Electric WaterHeater

Any EF - Any WaterHeater

EF68 - Gas Water Heater