Multifamily buildings are an important target for efficiency improvements because of their energy savings potential and housing market share. Yet few multifamily retrofit projects have been completed in hot-humid regions and even fewer studies have measured and verified savings from such projects. Addressing this gap, the purpose of our research is to assess the impacts of energy-efficiency upgrades to multifamily buildings in Orlando, FL. Specifically, we measure the first-year electricity savings from retrofits to 232 units in four apartment complexes. Annual savings per unit averaged 2094 kWh (22 %) and ranged from 1700 kWh (18 %) to 3811 kWh (29 %) across complexes. Monthly savings ranged from 48 kWh (9.4 %) in December to 340 kWh (31 %) in August. From these core findings, we estimate that tenants in treatment units saved an average of $272 on their electric bills. We also find evidence to support a strategy of targeting upgrades to improve overall savings and program cost-effectiveness. Results are being used to guide development of a utility demand-side management program for multifamily property owners. Progress in this market requires additional pilot projects, access to utility data, reliable measurement and verification of savings, and innovative financing structures.
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The fifth property (complex 5) was not included because retrofits were not applied in a uniform manner and the variation in ECMs among the apartment units made it unsuitable for this analysis. The “Data collection and screening” section provides additional details about the screen process for this analysis.
Although some M&V protocols recommend that annual energy savings estimates be weather normalized to reflect net savings for the “average year,” this analysis does not do so. In the year following the retrofits, there were 1.87 % less total annual degree days, measured from 20 °C, than in the year preceding the retrofits. Degree days were calculated using data from the US National Oceanic and Atmospheric Administration nNOAA) for daily temperatures at the Orlando Regional Airport in Orlando, FL.
Appendix A provides pre- and post-retrofit consumption for the full, unscreened treatment control groups, and for the screened treatment and control groups.
For households that were consistently occupied from January 2011–December 2011.
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The retrofit project described in this article was paid for, in part, by a grant from the Florida Energy and Climate Commission with funding from the United States Department of Energy (EE0000241), through the American Recovery and Reinvestment Act, and by the Orlando Utilities Commission. The research was sponsored, in part, by the Orlando Utilities Commission and by the John D. and Catherine T. MacArthur Foundation. The authors would like to acknowledge the work of Tom Gross and Cameron Saulsby, of the Orlando Utilities Commission, in collecting and providing detailed data from the apartment retrofits described in this article. We would also like to thank our colleagues Lynn Jarrett and Hal Knowles for their support in this work.
We measured energy savings from retrofits to 232 apartments in four building complexes.
Per-unit annual savings averaged 2094 kWh (22 %) and totaled 530 MWh.
Across complexes, average savings ranged from 18 to 29 %.
Average monthly savings peaked at 340 kWh (31 %) in August.
Tenants’ electric bill savings averaged $272/year and totaled $68,913.
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Taylor, N.W., Searcy, J.K. & Jones, P.H. Multifamily energy-efficiency retrofit programs: a Florida case study. Energy Efficiency 9, 385–400 (2016). https://doi.org/10.1007/s12053-015-9367-x
- Energy efficiency
- Demand-side management (DSM)
- Multifamily buildings
- Residential retrofits
- Impact assessment
- Electricity savings
- Measurement and verification (M&V)
- Project case study
- Hot-humid climate
- High-efficiency HVAC