Efficient electric hot water heating technologies significantly reduce the carbon emissions of multifamily buildings, according to a report by the American Council for an Energy-Efficient Economy (ACEEE) and New Buildings Institute (NBI).
In multifamily buildings with five or more units, water heating uses more energy than space heating, cooling, or lighting, the report says. Converting gas-fired water heaters to advanced technology—electric heat pump water heaters (HPWHs)—would cut greenhouse gas emissions from water heating by an average of 58%.
If HPWHs are powered entirely by clean sources, they cause zero emissions, making them a critical tool for decarbonizing the economy. Efficient electric water heaters carry a higher upfront cost over gas models, so policymakers would have to provide incentives to owners to make the conversion, the report says.
“Many utilities offer incentives for building or unit owners to install in-unit heat pump hot water heaters,” an ACEEE/NBI news release says. “Yet few programs are designed specifically for multifamily buildings, which offer unique challenges.”