When it comes to energy efficiency, multifamily rocks.
According to the latest count by NetZero, apartment properties now account for 75 percent of the total zero energy residential stock in Canada and the U.S.
Zero energy, or ZE, is defined as units that are built to “achieve energy performance in the realm of zero.”
Multi-unit projects account for 20,943 units in the ZE inventory, according to the 2019-2020 Zero Energy Residential Buildings Study, which documents six years of findings and operations. Single-family properties account for 5,745 ZE units.
“Multi-unit projects are (a) ZE mainstay,” according to the report, which was released recently.
The average single-family development, excluding one-house projects, is 24 units; the average multifamily project, 62 units. But overall figures are probably larger, the report advises, mostly because it is self-reported.
“We believe that the ZE housing stock is considerably larger,” the report states. “We know we can’t possibly reach every designer, builder, developer or owner of a ZE home.”
Also, the bulk of the properties included in the count are either in design, under construction and completed. Those in the “highly uncertain” conceptual stages are omitted. But while some certainly will not reach fruition, it is worth noting that 30,726 ZE units in 38 projects are on various drawing boards.
“ZE is continuing to show strong growth overall,” the report says. But “it’s reasonable to conclude that we’re capturing only a fraction of the ZE planning pipeline.”
One recent example of the lengths some multifamily developers are going in the name of sustainability is The Walk-Bainbridge, a 52-unit townhouse rental property on Bainbridge Island across from Seattle. The project was named this year’s top multifamily development by Green Builder Media.
With 500-plus solar panels, the property is designed with enough solar capability to provide more renewable energy than it uses. A series of micro-inverters on roofs, awnings and vertical end walls collect the energy. Elsewhere in the community, the flooring consists of sustainably harvested wood and wool carpets, ductless heat pumps provide heavily filtered air and electric car chargers are placed throughout.
Another award-winner, Third Avenue Development in the Bronx’ Morrisania neighborhood, was named the Best Green Affordable Multifamily Community by the National Association of Home Builders. The eight-story, 30-unit structure has 14 units for low-income households, eight for moderate-income occupants and eight others set aside for the homeless.
The building, which replaced a dilapidated three-story auto shop as well as a vacant residential structure, features green roofs, skylights, energy recovery ventilators, variable refrigerant flow heating and cooling systems and energy efficient windows, lighting and appliances. Individual HVAC units allow residents to control for comfort in their apartments, but allow management to control the range of heat and cooling within each unit.
According to the report, zero energy is no longer a custom niche. “The clear takeaway is that nearly all of residential ZE construction is driven by business.”
Top of the List
California heads the list of states with the most ZE units, 10,959. New York is a distant second with 3,332, followed by Ontario with 2,226, Arizona with 1,603 and Colorado with 1,311.
The builder with the most units is Sifton Properties of Ontario, with 2,001. The Corporation for Better Housing, a California non-profit which serves low-to-moderate income seniors and families, has 1,281 units, followed by Mandalay Homes with 1,192 units and Handel Architects with 1,002 units.
The top architects in the field are ZeroEnergy Design, with 22 projects in New England, Deltec Homes with 11 projects in four states, Marken Design and Consulting with eight properties in Canada, and Green Hammer Design Build with seven projects in Oregon and Washington.
Though it is not broken down by single or multifamily, it is worth noting that most projects—69 percent—are all-electric. The second most popular fuel is natural gas. But some are fueled by wood, propane and geothermal. One is even powered by pellets.
Also, 96 percent include photovoltaics, an array of which are typically roof-mounted, and 22 percent include electric vehicle charging stations.
In its simplest terms, a zero net energy building produces as much renewable energy as it consumes. While photovoltaics are the most common energy source, net zero is usually achieved by reducing energy demands while producing energy at the same time.
Relatively inefficient properties where solar was added, perhaps as an afterthought, “don’t come close” to meeting annual energy demands are not included, nor are projects touted as zero net energy but are actually only zero net electricity.