Steven Bluestone and Henry Gifford

Improving Energy Efficiency in Affordable Multifamily Buildings

Affordable multifamily rental housing units in cold climates are often heated by large, central boiler systems that make it difficult to directly meter individual apartment heating energy use. While some tenants might do the right thing by keeping windows closed and lowering thermostats in winter, others do the opposite, resulting in energy inefficiencies and increased heating costs for landlords. At the same time, builders are not incentivized to build more energy-efficient buildings; the result is that there is no motivation for either the builder or the residents to save energy. However, the technology exists to overcome these disincentives to change. In the past decade, significant advances have been made in building envelopes and HVAC equipment—particularly in the technology of air-source heat pumps, which has improved to such an extent that they are now widely used by leading practitioners in the “Net Zero Energy” and “Passive House” movements.

In this session Henry Gifford and Steve Bluestone will share the results of a three-year laboratory-style study that measured the efficiency of an electric air-source mini-split heat pump system which could be used in multifamily units to effect significant energy savings.  The presenters will also provide detail about a 101-unit affordable rental building under construction in New York City which will be heated and cooled by electric air-source heat pumps connected to each apartment’s electricity panel. The goal is to have the tenants pay for their own heat, which would give them an incentive to keep their apartment windows closed throughout the heating season; rents will be lowered by a fair value based upon the realities of the design and equipment being used. The session will also explore legal issues relating to electricity sub-metering and the complications raised in dealing with regulatory bodies such as the New York State Public Service Commission.

Follow along with the presentation by  downloading it here.