Ductless Heat Pump Retrofits in Multifamily and Small Commercial Buildings

This study evaluates the electricity savings that can be gained by installing ductless heat pumps (DHPs) in multifamily and small commercial applications. A total of 12 multifamily units were submetered in two localities; 188 units were included in the accompanying utility billing analysis. Ten small commercial sites were evaluated. The estimated heating savings for multifamily installations is 824 kWh/year. This is based on an average of the heating savings at the two complexes. The Cooling Zone 2 site showed some cooling savings, but we expect that cooling savings in hotter climates will be balanced out by takeback in milder climates that are adding cooling capability.

With savings of only 824 kWh/year and an assumed measured cost of $3000 for a single indoor head system, the economics of the installation are far from favorable. Assuming a 16 year measure life and a real discount rate of 4%, the levelized cost of the DHP savings is $0.28/kWh, almost three times the Northwest Power and Conservation Council (NWPCC) threshold of $0.101/kWh. Small commercial sites with consistent occupancy, and which do not have high internal gains or process loads, show significant opportunities for savings. Six of the ten sites metered are consistent with office and retail use patterns. Those six sites saved, on average, 4,185 kWh/yr. The remaining four sites represent commercial building types requiring further research.

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