Report Released: Using an Aerosol Sealant to Reduce Multifamily Envelope Air Leakage

Jan 4, 2017

CEE has released the final report on its research demonstrating and modeling air leakage reduction and energy savings from air sealing new multifamaily units using the aeroseal process: Demonstrating the Effectiveness of an Aerosol Sealant to Reduce Multi-Unit Dwelling Envelope Air Leakage. 

Multifamily buildings have many of the same leakage paths as houses, as well as additional paths hidden in walls or other cavities that are difficult to seal with conventional methods. The aerosol envelope sealing technology, Aeroseal, developed by the Western Cooling Efficiency Center at UC Davis, can seal leaks in building walls, floors, and ceilings. This automated process has the potential to be more effective and convenient than conventional sealing methods and produce an extremely tight envelope.

set-up-cropped.jpgThe Aeroseal sealing process works by blowing air into a unit while an aerosol sealant “fog” is released in the interior. As air escapes the building through leaks in the envelope, the sealant particles are carried to the leaks where they impact and stick to the edges of the leaks, eventually sealing them. A standard house or duct air leakage test fan is used to pressurize the building and provide real-time feedback and a permanent record of the sealing. The technology is thus capable of simultaneously measuring, locating, and sealing leaks in a building. 

The objectives of the study were to:

  • Measure the envelope leakage reduction and final tightness,
  • refine the unit preparation and sealing process, 
  • model the impact of envelope tightness on outdoor air and inter-unit air flow rates, and
  • estimate energy savings for tighter envelopes.

Research findings
The aerosol envelope sealing of new construction and existing building units successfully demonstrated high levels of air leakage reduction with no damage to the finished surfaces.

For the new construction units the reduction varied from 67% to 94% with an average of 81%. All of the units were more than 50% tighter than the 3.0 ACH50 code requirement for low-rise residential buildings, and half  of the units met the Passive House tightness requirement of 0.6 ACH50. In addition, all of the units were at least 80% tighter than the EPA ENERGY STAR Multifamily High Rise requirement of 0.3 CFM50/ft2.

This project was supported in part by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD) program. The project was co-funded by CEE in support of its nonprofit mission to advance research, knowledge dissemination, and program design in the field of energy efficiency.

Related Links
Full Report: Demonstrating the Effectiveness of an Aerosol Sealant to Reduce Multi-Unit Dwelling Envelope Air Leakage
Webinar recording on project findings
Research project page