Table 1. Energy Impact Summary Participant Groups Annual Gas Savings (in ccf) Annual Electricity Savings (in kWh) Annual Cost Savings Lifetime Cost Savings Program Cost Benefit/Cost Ratio Single family: gas heat  320 300 $220 $2,700 $2,600 1.0 Multifamily: gas heat  220 200 $140 $1,800 $1,700 1.1 Single family: electric heat 0 2000 $180 $2,200 $1,910 1.2 Multifamily: electric heat 0 900 $80 $1,000 $910 1.1 Note: Lifetime cost savings are the net present value of the energy savings over the life of the measures. Program costs include all HWAP and utility weatherization spending, including HWAP administrative costs (local provider management; state office management; and fiscal and technical monitoring, training, and evaluation costs) but exclude health and safety measures that are not performed for energy savings. Benefit/cost ratio does not include non-energy benefits.

"I've been in seventh heaven ever since [the weatherization crew] were here," says Juanita Hiser, a 74-year-old widow on a fixed income. "Not only is my house more comfortable, but my energy bills have gone down quite a bit."

Tony Sykes, a case manager supervisor with the Mid-Ohio Regional Planning Commission (MORPC), installs cellulose insulation into a sidewall using the tubing method. MORPC is one of the HWAP grantees in the Columbus area.

Table 2. Cost-Effectiveness of Selected Measures in Gas-Heated, Single-Family Homes Measure Annual Gas Savings (in ccf) Annual Cost Savings Present Value Savings Cost * Benefit/Cost Ratio Wall insulation 180 $110 $1,300 $680 2.0 Wall insulation (dual effect) 210 $120 $1,500 $680 2.3 Attic insulation 150 $90 $1,100 $470 2.3 Air sealing 110 $60 $780 $430 1.8 Heater replacement 150 $90 $1,100 $1,500 0.7 Note: Heating system replacements are performed only for safety reasons, not for energy savings. Floor insulation and heating system tune-ups are not shown, since we found no savings attributable to them. Wall insulation (dual effect) includes the estimated savings from the air leakage reductions that the insulation provides.  *There is some uncertainty regarding cost allocations because per-measure costs were not tracked, so they had to be estimated based on statistical analysis and past experience in cost allocations for this type of program.

For the 244 gas-heated multifamily units, the average reduction in gas usage following weatherization was 251 ccf per year; for the 2,209 gas-heated single-family homes, the reduction was 324 ccf per year (see Table 1). This represented 23% of total usage and 29% of heating usage for the single-family homes.

The 150 electrically heated single-family homes and 116 electrically heated multifamily units averaged a savings of 2,000 kWh per year, which represented 9% of total usage and 17% of heating usage.

High Savers--No Surprises

An analysis of the cost-effectiveness of selected measures was done on the single-family homes. As expected, wall insulation was estimated to provide the most savings--183 ccf per year (see Table 2). (Attic insulation provided savings of 148 ccf per year.) An estimate was made of the total effect of wall insulation, including its air sealing benefit, by analyzing the relationships among blower door reductions, program treatments, house size, and the initial air leakage rate. According to this analysis, the wall insulation was responsible for about a 0.37 CFM₅₀ leakage reduction for each ft² of wall insulated. When this effect was included, the total savings attributable to wall insulation was estimated at 221 ccf per year.

Low Savings in Floor Insulation

The lack of savings for floor insulation was surprising. Many of the units that received floor insulation were mobile homes. Although customers reported increased comfort as a result of the warmer floors, the decrease in heat loss was not enough to result in measurable energy savings. One-fourth of all the homes received duct sealing, but the observed savings were not significant.

In terms of cost-effectiveness, using a real discount rate of 5%, attic and wall insulation provide savings worth twice their cost. To improve the overall cost-effectiveness of the program, the evaluation report recommends that consideration be given to a low-cost program for units with a small potential for energy savings, targeting services to high-use households. It also recommends baseload electric measures such as compact fluorescent lighting for frequently used lights, photocells and motion detectors for exterior lighting, removal of secondary refrigerators or chest freezers, and replacement of low-efficiency primary refrigerators.

Highest Savings Seen

In addition to calculating the energy savings and cost-effectiveness of Ohio's HWAP, the evaluation examined the impact of the program on customer payment behavior and on Ohio's Percent of Income Payment Plan for the low-income customers of regulated utilities.

Home Energy can be reached at: contact@homeenergy.org
Home Energy magazine -- Please read our Copyright Notice