Why weatherize your attic?
As part of a no-cost energy assessment provided by Mass Save, experts will assist you in evaluating your property’s energy efficiency. If your attic is accessible, they will focus on your attic’s air sealing and insulation. They will help coordinate air-sealing and insulation services with weatherization installers, offer energy-saving products for you to install, and suggest upgrades, if necessary.
These professionals have a trained eye for spotting common sources of air leaks. However, the most comprehensive way to find hidden leaks is through a professional assessment using a blower door. This device pressurizes your building to reveal leaks. While a blower door test isn’t typically included in a complimentary Mass Save energy assessment, it’s often worth making the investment of $300 to $600 to have this done. It could help uncover even more opportunities for improving weatherization.
Weatherization is one of the most impactful ways to protect your building, reduce demand on your share of the property’s heating and cooling bills, and give your tenants a more comfortable rental all at the same time.
Air sealing
Since heat naturally moves upward, it is important to limit air leaks between any living areas and the attic. These leaks can contribute to as much as 40% of the costs to condition the indoor space in a leaky building. Making sure there are minimal gaps for airflow in the attic is a key first step. Remember, air-sealing should be completed before adding insulation. Using the following products to seal your attic can greatly reduce the amount of heating and cooling needed in the living space below.
- Caulk – best for small gaps
- Spray foam – best for medium to large gaps
- Foam weatherstripping – best for attic windows and access doors
- Gaskets – best for electrical boxes, outlets, and recessed lighting
Insulation
Insulation works by slowing the movement of heat through your building’s walls, roof, and floors. This is crucial because heat transfer is the primary reason for heat loss during winter and heat gain during the summer. Different types of insulation are available. Ask your installer what will work best for your attic:
- Blown-in cellulose (a loose, plant fiber-based material)
- Fiberglass (either blown-in or blanket-like “batts”)
- Spray foam
The effectiveness of insulation is measured by its “R-value,” which indicates how well it resists heat flow; higher numbers mean more insulating. For attics, Mass Save recommends an insulation level of R-49. To reach this level, you’ll need around 15 inches of thickness using materials like fiberglass or cellulose to evenly cover the attic floor, or a combination of the two. This insulation will play a significant role in keeping your building energy efficient.
