Why Air Sealing and Insulation are Both Essential

Posted by: Rate It Green Team

Why do we need to air seal AND insulate? The answer is that these control layers work together to protect air quality and energy efficiency, improving comfort, protecting our building assets, and saving energy and money.  If we don’t have a good air seal, pollutants get through the insulation and we end up using insulation as a filter.  This means the insulation will be compromised, and pollutants and even pests are more likely to enter buildings.  

A good air barrier helps insulation work properly.  Without an effective air barrier, air leaks though the insulation and heat loss is therefore only slowed a little.  

A good tight envelope with properly installed insulation and an air barrier means homeowners and occupants will use less energy.  For builders this means an HVAC system can be downsized, or even let’s just say right-sized.

Why so much focus on air sealing?  It's important to understand that air sealing, insulation and other weatherization activities to seal and protect buildings from the elements are the most cost effective steps one can take to make a building more energy efficient.  Put simply, air sealing costs the least and delivers the maximum benefit.  This is true for all building types and whether a builder is building a code compliant building or is aiming to build a more sustainable or super tight building. It's also notable that, as Matt Hoots warns us, air  sealing is both the easiest thing to master and the easiest thing to get wrong...  So, let's make sure to take the time, care, and attention to detail to get it right! 
 

If you'd like to learn more about proper air sealing and insulation, check out these related topics:

• Pros and Cons of an airtight house
• What is ACH50, and Why does it Matter?
• What is a "Water Resistant Barrier" (WRB), Examples and Misconceptions
• The “Perfect Wall” Defined and Demonstrated
• 50% of the "Perfect Wall" Control Layers with One Product

For innovative ways to insulate, check out the #1920sMakeoverATL Showhouse. For this project, Green Builder Matt Hoots and the team will not only meet the Georgia and National energy codes, but will also meet the Passive House Standard for airtightness and energy efficiency.


Insulation without proper air sealing is essentuially used as a filter and will not work optimally. 


Without a proper air seal, pollutants will find their way through insulation into our buildings. 


Insulation without air sealing is much less efficient. 


Green Builder Matt Hoots, and Oliver. Oliver is very knowledgeable about green building!