Attic Air Seal and Insulation

Every house and every attic space is different, but there are two main approaches to properly insulating and sealing attic spaces:


Keep the House Comfortable and Let the Attic follow Seasonal Temperatures

For a majority of homes, this approach is the most cost effective way to improve the comfort and efficiency of a house.  The idea is to create a perfect insulation and air barrier to separate the attic space from the living space so that no matter how cold or hot it gets in the attic the inside living space is not affected.  Common air leakage locations are at the tops of interior and exterior walls; electrical, mechanical, and plumbing penetrations into the attic; utility chases for ductwork and chimney flue pipes; recessed light fixtures; and access hatches and stairs. Each individual area is treated differently, but typically involves the application of spray foam to seal air leaks. Eliminating air leakage into the attic helps reduce the amount of hot air that escapes the house in the winter and also reduces how much cold air gets pulled in the lower levels.  This evens out the temperatures throughout the house. In addition, attic insulation performs more effectively when installed on air is not leaking through it. In most homes, sealing attic air leaks makes a larger impact on the comfort and energy efficiency of a house than even adding attic insulation.

Insulation levels in attic spaces in homes older than 10 years are commonly lower than the current building code of R-49 (18.5” of Insulation).  Sometimes the insulation throughout the attic is lower because it has never been upgraded, but sometimes the insulation has been trampled or moved by previous homeowners or maintenance technicians, or wind blowing through the eaves.  Installing new insulation to bring the house up to code can significantly reduce the amount of heat that is lost into the attic in the winter and heat this pulled down from the attic in the summer.

Keep the Attic the Same Temperature as the Rest of the House

Some attic spaces are so well connected to the house and have so many utilities in them, that it is actually more cost effective to insulate the underside of the roof and heat the spaces rather than trying to separate them from the living space.  Cape Cod style houses or houses with dormers are ideal candidates for this approach. In most cases, existing insulation in these spaces is removed and spray foam is installed. These types of attic improvements greatly improve the comfort of the top floor of the house while evening out temperatures throughout the house and reducing heating and cooling costs.

An Atlas Energy Auditor can determine which method of improving your specific attic will help you meet your goals of comfort and energy efficiency while minimizing investment costs and time.