Internet resources help evaluate energy savings from rebate program

Editor's note: The Energy Services Bulletin features real answers to real questions posed to our staff at the Energy Services Power Line. We hope you find it useful.

Question:

Our utility is analyzing several residential rebate programs that we have already paid out in an effort to assign an energy value to those rebates. The equipment covered included:

• central air conditioner
  
• room air conditioning
  
• refrigerator
  
• washing machine
  
• whole house fan—new installations only (versus no fan)
  
• low-e windows and low-e window film treatments
  

We would like to determine an average on savings.

Answer:

Assigning precise energy values to your now-completed residential rebate program was difficult to do without having more specifics. You'll want to keep that in mind when designing future rebate programs. However, our library was able to come up with some information that should be useful.

Since refrigerators are the most energy-intensive home appliances, there is quite a bit of information available about potential energy savings.

An article in the January/February 1995 issue of the online Home Energy magazine, "If a Spare Refrigerator is Running Edison Wants to Catch it," has more on refrigerator energy use.

According to the article, Southern California Edison estimated energy savings for its refrigerator recycling program with existing data instead of randomly metering incoming refrigerators. Test data came from similar utility programs around the country, metering studies done by ARCA, and "book standards and values" for different vintages available from the Association of Home Appliance Manufacturer.

Edison program statistics estimated that as of August 1994, 24,000 refrigerators and freezers had been picked up, saving customers the cost of 30 million kWh of energy (an average of 1,250 kWh per unit), with a demand reduction on the Edison system of 4,500 kW.

The following results from actual utility rebate programs were excerpted from the American Council for an Energy Efficient Economy 2002 Summer Study on Energy Efficiency in Buildings:

Refrigerator Replacements for the Weatherization Program

Figure 5. Energy Use of Existing Indiana Refrigerators and New 18-cubic-foot Replacement Units:

Average consumption	1601 kWh per year
Replacement units use	434
Savings	1167

A Profile of a Refrigerator Recycling Program

Table 8: Savings Details by Size Categories

Refrigerator: 1,552 Average UEC (unit energy consumption – probably in kWh per year).

ACEEE also lists the top-rate energy-efficient appliances, including refrigerators and freezers on its Web site. Here is an excerpt:

A typical new refrigerator with automatic defrost and a top-mounted freezer uses less than 500 kWh per year, whereas a typical model sold in 1973 used over 1,800 kWh per year.

Energy Star published a fact sheet, Reducing Appliance Energy Use, which gives savings for several household appliances:

Refrigerators:

An average older model uses more than 1,000 kWh per year. New models that meet the Federal applicant efficiency standards use 800 kWh per year, and Energy Star qualified refrigerators use less than 600 kWh per year.

Air Conditioners:
	Central (30,000 BTU)
		Conventional	SEER 7.5	720 kWh per month
		Conventional	SEER 10	540
		EnergyStar	SEER 13	414
	Room (8,000 BTU)
		Conventional	EER 7.5	193 kWh per month
		Conventional	EER 10	144
		EnergyStar	EER 11	131
Dishwasher (one load per day; not including hot water):
		Conventional unit	58 kWh/mo.
		Energy Star unit	46
Clothes washer (25 loads per month; electric water heater)
		Conventional	68 kWh/mo.
		Energy Star 2	9

Information about windows replacement was harder to find. The 2002 ACEEE Summer Study on Energy Efficiency in Buildings published "ENERGY STAR Labeled Windows: Establishing an Effective Market Transformation Program," which gives the following data:

Table 3. Normalized Therm Savings
	Therm Savings per Dollar Rebate: 0.18
	(0.18 therms equals 5.28 kWh)

Check out the Efficient Windows Collaborative for data relating to window types and heating and cooling savings. The following fact sheets may be useful:

For Utilities: Total Air Conditioner Power Requirements for Regular Double Glazing and Low-e Glazing

Energy and Cost Savings

Selecting Energy Efficient Windows in California

We did not find much useful data on energy savings with the use of a whole-house fan; there are so many variables. The following statistic comes from the Consumer Guide to Home Energy Savings, American Council for an Energy-Efficient Economy, 1999, p. 188.

Table 12.1 Typical Energy Consumption …
	Whole-house fan 20-500 kWh per year

Several online databases give examples of how other utilities measure and verify savings. The California Measurement Advisory Council, which evaluates studies for California energy efficiency programs conducted by member organizations, maintains a searchable database. We performed a search on residential + rebate, and came up with 38 programs.

The Market Assessment and Program Evaluation Clearinghouse, sponsored by the Consortium for Energy Efficiency, is a fully searchable, user-friendly, web-based database that contains more than 300 evaluation reports, market characterization studies and market assessments. Users can search the database by sector, region and category. The sample results below used "residential," "California" and "program" evaluation as the parameters.

Impact Evaluation of PGE's 1996 Residential Appliance Efficiency Incentives Program (March 1998)

Publisher	Pacific Gas & Electric Company
Summary	This report presents results of the First Year Load Impact Evaluation of Pacific Gas & Electric Company's 1996 Residential Appliance Efficiency Incentives Programs, and addresses the refrigeration and lighting end uses. For the project, both gross and net impact estimates were developed for energy consumption (kWh) and electric demand (kW). Both refrigeration and lighting gross impacts were developed using an engineering approach. All operating and fixture confirmation data were collected via on-site surveys. For refrigerators, savings were found to be correlated with size, on a percentages as well as absolute basis; the larger refrigerators had greatest savings. For lighting, the rebated measures appear to be associated with a mature market in which customers' are willing to purchase high efficiency equipment on its own merit without a rebate. The result is that evaluation net savings estimates are less than half of the PG&E net savings estimates. The existence of PG&E lighting efficiency programs over the past decade could have had significantly impact on the transformation of the lighting efficiency markets. However, this evaluation did not address market transformation impacts, and the narrow focus of the net-to-gross analysis may contribute to the low estimates of net-to-gross ratios. To view this document in its entirety, please go the website listed below and type in the title of the report. 121 p.
Author(s)	Xenergy

Contact
	Valerie Richardson, Supervisor, Marketing & Evaluation	(415) 973-6163
	Pacific Gas & Electric Company	vkr1@pge.com

The National Center for Appropriate Technology Residential Energy Efficiency Database is an up-to-date and comprehensive listing of utility programs, which can be searched in various ways.

Western's Utility Options Database, lists programs that are innovative or unique. None of the entries specifically addressed measuring and verifying program savings. Searching with the keywords, rebate and residential found three programs that offer residential appliance rebates:

Lodi Electric Utility, Pasadena Water and Power (whole house fan rebates) and Columbia River People's Utility District

Contact the utilities directly to ask about savings per appliance, or methods for measurement and verification

Sacramento Municipal Utility District might also be willing to share insights about measurement and verification of program savings. Contact the residential energy services coordinator at 1-888-742-7683.

Finally, the California Energy Commission offered an "Emerging Renewables (Rebate) Program" to residential and other customers throughout California. Visit the Database of State Incentives for Renewable Energy for information about the program and contact numbers.