Multifamily buildings pose a conundrum for advancing energy performance. As a building type, they are caught somewhere between commercial buildings and single-family residences – they are often constructed like commercial buildings, yet used as residential buildings. Energy-efficient technologies and design strategies that work for commercial or single-family homes are often ineffective for multifamily buildings.
This situation is further complicated in that energy codes for multifamily buildings are divided between residential and commercial energy codes. High-rise multifamily buildings (those four stories and higher) are regulated by commercial codes such as ASHRAE Standard 90.1 or the commercial section of the International Energy Conservation Code (IECC), which focus on commercial loads and usage patterns. Multifamily buildings under four stories are regulated by the residential section of the IECC which is written for single family homes. With their residential usage patterns and loads, yet larger size, higher occupant density and greater frequency of central mechanical systems and common areas, neither code is a good fit.
New Buildings Institute’s (NBI) new Multifamily Guide from our Building Innovations program works to reconcile this gap between code and building use. It recommends advanced energy efficiency measures that offer energy savings for all sizes of multifamily buildings under either code, and provides guidance to resolve key issues for multifamily buildings.
Strategies–addressing envelope, space conditioning, ventilation, lighting, water heating and appliances–offers savings individually, or can be bundled for greater impact. Models show that implementing these efficiency measures in a multifamily building could achieve savings of 15-25% over the 2015 International Energy Conservation Code. The descriptions and specific requirements in the guide cover aspects of multifamily building performance that are insufficiently addressed by current code, such as thermal bridging, infiltration, ventilation and equipment performance.
For even greater savings, the guide includes a series of additional efficiency options that can also be implemented individually or bundled. Savings as high as 40% can be achieved using these additional measures in some regions. Furthermore, the guide offers advanced guidance where market practice significantly lags behind best practice and where technology advances have created design challenges. This guidance can help practitioners implement energy efficiency measures more successfully.
The Multifamily Guide aims to close the gap between the construction and use of multifamily buildings, and the code regulating them. This is a bundle of advanced measures and guidance that can be used by both the market and and energy efficiency incentive programs to advance the energy performance of the multifamily market.
Download the guide at: https://newbuildings.org/product/multifamily-guide/.
To learn more about how efficiency programs can utilize this work for better outcomes, visit: https://newbuildings.org/hubs/new-construction/multifamily-new-construction-guide.
by Sean Denniston, Senior Project Manager