The National Fuel End-Use Efficiency Field Test: Energy Savings and Performance of an Improved Energy Conservation Measure Selection Technique

The performance of an advanced residential energy conservation measure (ECM) selection technique was tested in Buffalo, New York, to verify the energy savings and program improvements achieved from use of the technique in conservation programs and provide input into determining whether utility investments in residential gas end-use conservation are cost effective. The technique analyzes a house to identify all ECMs that are cost effective in the building envelope, space-heating system, and water-heating system. The benefit-to-cost ratio (BCR) for each ECM is determined and cost-effective ECMs (BCR > 1.0) are selected once interactions between ECMs are taken into account. Eighty-nine houses with the following characteristics were monitored for the duration of the field test: occupants were low-income, houses were single-family detached houses but not mobile homes, and primary space- and water-heating systems were gas-fired. Forty-five houses received a mix of ECMs as selected by the measure selection technique (audit houses) and 44 served as a control group. Pre-weatherization data were collected from January to April 1988 and post-weatherization data were collected from December 1988 to April 1989. Space- and waterheating gas consumption and indoor temperature were monitored weekly during the two winters. A house energy consumption model and regression analysis were employed to normalize the space-heating energy savings to average outdoor temperature conditions and a 68 F indoor temperature. Space and water-heating energy savings for the audit houses were adjusted by the savings for the control houses. The average savings of 257 therms/year for the audit houses was 17% of the average pre-weatherization house gas consumption and 78% of that predicted. Average space-heating energy savings was 252 therms/year (25% of pre-weatherization space-heating energy consumption and 85% of the predicted value) and average water-heating savings was 5 therms/year (2% of pre-weatherization water-heating energy consumption and 17% of predicted). The overall BCR for the ECMs was 1.24 using the same assumptions followed in the selection technique: no administration cost, residential fuel costs, real discount rate of 0.05, and no fuel escalation. A weatherization program would be cost effective at an administration cost less than $335/house. On average, the indoor temperature increased in the audit houses by 0.5 F following weatherization and decreased in the control houses by 0.1 F. The following conclusions regarding the measure selection technique were drawn from the study: (1) a significant cost-effective level of energy savings resulted, (2) space-heating energy savings and total installation costs were predicted with reasonable accuracy, indicating that the technique's recommendations are justified, (3) effectiveness improved from earlier versions and can continue to be improved, and (4) a wider variety of ECMs were installed compared to most weatherization programs. An additional conclusion of the study was that a significant indoor temperature take-back effect had not occurred.