US Department of Energy

Workshop on Water Heaters

Comments Received on

Water Heater Analysis

vt

EE-RM-97-900 COMMENT 78EE
Comment Issues

Engineering (venting, heat traps, hot water usage and insulation blowing

agent)

Small water heater closets

Price and markup (gas equipment markups and installation costs)

Marginal energy rates

LCC analysis (RECS data and blended fuel projections)

National energy savings analysis (fuel switching)

Measured EF versus rated EF

Standards recommendation

2

EE-RM-97-900 COMMENT 78EE
Engineering Issues

Venting

Comment: GAMA claims recovery efficiency (RE) should not exceed 76% to

maintain adequate margin of safety. Bradford White says 78% is

maximum to avoid corrosion in vent; ACEEE believes 80% is viable.

Response: 78% RE is 5.5% below the Fuel Loss Efficiency limit for

condensation in the vent system as determined by GRI.

Heat traps

Comment: DOE should use the same, lower, values for the effect of plastic

and metal heat traps on energy factor than used in the analysis.

Response: Data provided by GAMA and Bradford White are being

considered.

3

EE-RM-97-900 COMMENT 78EE
Engineering Issues

Hot water usage

Comment: DOE does not have sufficient data on each of the factors considered

to model hot water use, it should consider household size only.

Response: The principle factor in the hot water usage model is household size.

The model is applied to RECS data, which show that households with gas

water heaters are on average larger than those with electric water heaters.

Comment: Do we account for impact of possible clothes washer standards?

Response: No.

4

EE-RM-97-900 COMMENT 78EE
Engineering Issues

Insulation Blowing Agents

Comment: DOE should perform life-cycle-cost and national energy

savings analyses with HFC-245fa as well as water-blown foam.

Response: DOE will add HFC-245fa analyses.

5

EE-RM-97-900 COMMENT 78EE
Small

* Water Heater Closets

Comment: Consumer choice of certain types of water heaters, e.g.,

tabletop or "lowboy" electric water heaters 36" or less in height, may

be reduced or eliminated by thicker insulation.

Response: In our analysis, we have added installation costs for 10 percent

of the water heaters inside the house this number is larger than the

market share of lowboys. We believe that manufacturers also can

address this issue in their design process.

6

EE-RM-97-900 COMMENT 78EE
Price and Markup

Gas equipment markup

Comment: Gas water heater markup is too low; the markups for gas and electric

should be the same.

Response: Based on industry data, we find different markups for gas, electric and

oil water heaters.

7

EE-RM-97-900 COMMENT 78EE
Price and Markup

Installation costs

Comments: We received comments on the differences in installation costs

among gas, electric, and oil; that installation and maintenance costs for gas

and oil are too low; and that we should add cost for condensate removal.

Response: Installation costs are based on information from plumbers and

water heater distributors. Assumptions:

Electric: $160 to remove and replace door jamb on 10% of water heaters

inside the house.

Gas: Type B vent costs for 78% RE and Type B vent plus chimney

relining for 80% RE in 25% of homes above 5000 HDD.

No condensation with gas or oil water heaters

8

EE-RM-97-900 COMMENT 78EE
Marginal Energy

Rates

Comment: Consumer marginal energy prices are not being calculated

correctly for either gas or electricity, e.g., Inflator93 and fixed costs.

Response: We calculated marginal energy prices for each household

based on RECS 1993.

Comment: Does DOE use different distribution curves for marginal

electric prices?

Response: Yes, we develop separate curves for summer and winter rates.

9

EE-RM-97-900 COMMENT 78EE
Life-Cycle-Cost

Analysis

RECs Data

Comment: Why isn't DOE using the most recent RECs data?

Response: Detailed 1997 RECS database not yet released, we are

considering using these data for the final rule.

Comment: RECS database may have errors, e.g., incorrect fuel type.

Response: RECS database provides broadest range of data available on U.S.

households.

10

EE-RM-97-900 COMMENT 78EE
Life-Cycle-Cost

Analysis

RECs Data, cont'd

Comment: Analysis uses household characteristics not found in the

database.

Response: Volume inferred from small/medium/large categories.

Thermostat setpoint temperature, cold water inlet temperature, and

room air temperature calculated using climate and household heating

degree days.

Natural gas and LPG price projections

Comment: DOE appears to be using a blended price projection.

Response: We used fuel prices from each RECS household and corrected

them to 2003 prices.

11

EE-RM-97-900 COMMENT 78EE
National Energy

Savings

Fuel switching

Comment: It appears the analysis is biased toward showing impacts on

fuel switching.

Response: In the analysis, we take current market share of water heaters,

by fuel type, and assume fuel switching may occur only in new

construction, and that in existing households, water heaters are

replaced with the same fuel type.

12

EE-RM-97-900 COMMENT 78EE
Measured EF vs. Rated EF

Comment: Rated EF's are higher for high efficiency electric water

heaters than models and testing would predict. What is DOE going to

assume, rated or tested values, for the analysis?

Response: Based on available data, DOE believes high efficiency water

heaters are overrated by approximately 0.02 EF. DOE will use the

lower values in its analysis.

13

EE-RM-97-900 COMMENT 78EE
Standards

Recommendation

Comment: GAMA suggested a standard of EF = 0.88 and 0.57 for

electric and gas water heaters, respectively.

Response: These are approximately equal to trial standard level 2.

14

EE-RM-97-900 COMMENT 78EE