Energy-Efficient Multifamily Housing

As demand for apartments and condos rises, builders and building owners of multifamily buildings are prioritizing energy efficiency to make their properties especially attractive and affordable.

Rising Need for Multifamily Housing

Multifamily buildings – which usually consist of five or more units – make up about 18% of the nation’s housing. That percentage is growing because:

  • Over 80% of multifamily housing units are rented, and the number of people looking for rental apartments is growing due to uncertainty in home values, limited finances and the need for flexibility in the event of relocation.
  • Cost-conscious home buyers are turning to condos instead of single-family homes for their cheaper purchase price, utilities and transportation costs.
  • Multifamily housing often is closer to the office, stores and entertainment than single-family homes.

Energy Efficiency Opportunities

Compared with single-family homes, energy use is higher per square foot of living space in multifamily buildings because more people use energy-intensive resources like hot water.  As energy expenses climb along with square footage, it becomes even more important for builders and building owners to make multifamily housing as energy-efficient as possible. 

The good news: Thorough energy efficiency retrofits can decrease energy consumption and expenses by 30% to 75% in many multifamily buildings. Such energy-efficient improvements also boost occupant comfort.

Paying for Energy Efficiency Upgrades

Energy efficiency incentive programs and utility rebates usually go to single-family homes or duplexes, and capital can be in short supply for multifamily buildings with low- and moderate-income renters. However, builders and building owners are in luck: Both the ENERGY STAR and LEED designations for homes are being adopted for mid- and high-rise multifamily buildings.

Efficient Temperature Control for Multifamily Housing

In older, centrally heated buildings, opening the windows can be the only available thermostat during the winter. A recent Danfoss-Alliance to Save Energy event, which showcased efficiency strategies for New York City, highlighted a strategy that addresses this issue: thermostatic radiator valves (TRVs).

Danfoss-Alliance Event in NYCMore than half of New York City’s residents live in the city’s 1.7 million multifamily housing units, and most do not have thermostats that they can control. That means it’s common for tenants to open windows when their radiators get too warm. To clamp down on this energy waste, two Upper West Side co-ops installed TRVs. The installations put the co-ops on the road to getting a return on their investment in three years. Based on these results, the NYC Mayor’s Office projects that if every multifamily building in the city installed TRVs, they could save $100 million annually.

Photo: Speakers at the “Energy Efficiency: The Path to NYC’s Residential Transformation” briefing. From left to right: NYC Department of Buildings Chief Sustainability Officer Deborah Taylor; Rep. Paul Tonko (D-N.Y.); Alliance President Kateri Callahan; Danfoss Vice President Robert Wilkins; Danfoss Director of Corporate Communications and Public Relations Lisa Tryson; NYSERDA President and CEO Frank Murray; NYC Mayor’s Office of Long Term Planning and Sustainability Green Codes Fellow Tom Sahagian.

Efficient Windows for Multifamily Housing

Whereas TRVs can cut down on the heat escaping through open windows, property owners are turning to energy-efficient windows to keep their multifamily buildings insulated. The Alliance’s Efficient Windows Collaborative offers a variety of resources for multifamily buildings:

Efficient Washing Machines for Multifamily Housing

Because many multifamily buildings have coin- or card-operated washing machines, the first step building owners can take to save energy in the laundry room is to use ENERGY STAR-qualified clothes washers, which consume about 37% less energy and 50% less water than standard commercial units.

To step it up, some multifamily buildings promote cold-water washing with incremental pricing on their clothes washers. These washing machines charge more for warm and hot water than they do for cold water, giving residents an incentive to use the less energy-intensive cold water option. For instance, several of Edgewood Management Corp.’s Washington, D.C.-area, multifamily buildings charge $1.25 for laundry loads with the cold-water setting, $1.50 for warm washes, and $1.75 for hot washes. Because residents have switched from almost exclusively using hot water to very often using cold water, the washing machines are consuming 25% to 30% less energy, according to Edgewood Assistant Vice President Terrence Kelley.