This was a collaborative master’s project between our team of graduate students at the University of Michigan’s School of Natural Resources and Environment (SNRE) and DTE Energy, the gas and electric utility in southeast Michigan. The project sought to assess the performance of the utility’s current home energy audit and retrofit programs, and recommend ways to increase program participation within DTE Energy’s residential customer base.
Many utilities across the country have trouble convincing residential property owners to undertake the necessary improvements and investments to enhance home energy efficiency—as is the case with our client, DTE Energy. Despite heavy marketing and promotional pricing, only a small fraction (less than 10% by current estimates) of DTE Energy customers participate in home energy audits. Amongst those who complete comprehensive audits, typically over half invest in home upgrades of some kind. Therefore, increasing participation in energy audit programs has significant potential to reduce energy costs, boost home value, and reduce greenhouse gas (GHG) emissions.
The DTE Energy Optimization (EO) group has recently run a residential efficiency pilot through the Home Performance Program. Our project team analyzed this pilot and the broader EO program and then made recommendations based on that analysis. We used surveys, interviews, monthly utility bills, pilot data, EO statistics, and census demographics to:
1. Quantify the effectiveness of the pilots to save energy and money overtime | calculating energy savings with pre- and post-retrofit billing data of weather-normalized gas and electricity usage,
2. Compare annual energy actual savings to modeled and deemed savings | contrasting actual savings to the results of energy modeling software and the public service commission’s Michigan Energy Measures Database,
3. Assess pilot and overall program performance through statistical analysis | analyzing the performance of pilot houses and the EO program in comparison to local, state, regional, and national averages,
4. Characterize home energy improvement services in Michigan | surveying residential auditors and contractors to understand how their businesses work and how they can be better served by the utility,
5. Find the motives that drive Michigan homeowners to energy efficiency | pinpointing the reasons for home energy auditing and retrofitting through interviews and relevant third-party surveys,
6. Identify customers who are likely to participate in future efficiency programs | using state census demographics and aggregated EO statistics to target specific homeowners for new EO initiatives.