Skip to content

Reducing Envelope Leakage in Multifamily Units with Aerosol Sealant


Construction practices in Minnesota for multi-unit dwellings have not produced the level of air tightness that has become standard practice for single-family houses. This is partly due to contractors’ lack of air sealing experience, but also because envelope openings in multifamily buildings are often hidden, diffuse, or inaccessible and difficult to address with conventional methods.

The goal of this CARD project (“Reducing Envelope Leakage in Multifamily Units with Aerosol Sealant”), awarded to the Center for Energy and Environment (CEE), is to demonstrate the effectiveness of an aerosol sealant to reduce envelope air leakage in multi-unit dwellings. Results will help inform whether or not this technology will support the launch of a pilot utility program using this approach to reduce building leakage in new and existing multi-unit dwellings.

In both laboratory and preliminary field tests by the Western Cooling Efficiency Center, aerosol sealing of the building envelope has shown promise to:

  1. Deliver low-cost sealing of numerous, diffuse leaks that are often inaccessible with conventional methods;

  2. Employ sealants that can be used in rooms with finished surfaces;

  3. Provide real-time leakage feedback for technicians to decide when continued sealing is no longer cost-effective; and

  4. Furnish automatic verification of the entire sealing process, certifying the performance of the building envelope.

In addition, this technology will work with any type of building construction, and is applicable to both new construction and to retrofits of existing buildings during tenant changeovers when the units are vacant.

Under this grant, CEE will design, build and test an injection system for the aerosol sealant system. As part of that process, the grantee will also develop installation protocols and procedures for delivering the aerosol sealant and establish the measurements that will be used to determine the impact of the envelope sealing process. Finally, CEE will quantify air sealing and energy savings in 15 to 20 apartments in at least two new construction buildings and in 8 to 12 apartments in at least three existing buildings.

This CARD project will run until the end of December 2015. For further information, contact project manager Eric Boyd or CARD Grant Program administrator Mary Sue Lobenstein.