You might think that it would be easy to track results for the  Recovery Act’s weatherization program. After all, simple, everyday energy bills provide a readily quantified measure of the benefits of home weatherization. Yet, as a recent GAO report noted, only a few states have already developed processes to measure the effectiveness of their weatherization program. With that in mind, we thought that states just starting out on this path might benefit from a look at Iowa’s long-standing assessment process.

Since 1992, Iowa has been tracking the benefits of its state low-income weatherization program, hiring Greg Dalhoff, a consultant with Dalhoff Associates LLC, to assess the costs and results of weatherization. Dalhoff pores over utility bill information and produces an annual report on energy savings provided by the weatherization program. The most recent report found that the first-year weatherization savings were $388 on average.

We asked Dalhoff what stood out to him, having reviewed weatherization and energy consumption for more than two decades. He pointed out two surprising findings, especially when considered in tandem.

The first thing he mentioned was that there was is a trend of decreasing consumption of energy in dwellings prior to weatherization. That is, people are using a lot less energy these days, even before they have their homes weatherized in order to save energy. “The big driver,” Dalhoff says, “is heating usage,” though he has yet to be able to conduct a thorough study of exactly what is causing the drop in consumption.

You might think that if your costs drop prior to weatherization, you'd expect to get a smaller percentage reduction from the actual weatherization process. After all, there are less total expenses from which to wring savings. But – surprise – it turns out that’s not true, according to Dalhoff’s second big finding:  “Normally, your percentage savings will tend to drop, but that 24-25% savings hasn’t changed much over the years.”

Beyond tracking savings at the statewide level, Dalhoff believes that  states just now launching performance review processes should appreciate the value of very targeted efforts.  “Any recommendations I make have been more at an agency level,” he says, “because every agency is going to be different”  Savings relative to expenditures will differ depending on the types of weatherization work various local agencies are doing, or what area and types of buildings they are working in.

Dalhoff’s one word of caution: “I am careful with how the data is used. Concerns of confidentiality haven't been a major issue,” he says. “Getting things started in another jurisdiction might be more problematic.”