Your home’s shell, or envelope, consists of the outer walls, ceiling, floor, doors and windows. Air leaks and poor insulation can disrupt the air quality of your home, causing your heating and cooling system to work harder to maintain your desired comfort levels. This can result in increased energy costs and wear and tear on your HVAC system. Sealing and insulating the home envelope can be easily achieved and will make a significant difference over time.
Tighten Up Your HouseTightening up the home envelope is a major part of the whole-house systems approach to energy efficiency. You can do most of the sealing and insulating yourself, or with the assistance of a knowledgeable contractor who can perform a blower door test to identify problem areas and provide expert help where needed. Seal any air leaks before adding insulation.
Sealing Air LeaksWhile every home needs a certain amount of fresh air to ensure good indoor air quality, it shouldn’t come in through leaks or cracks around doors, windows or walls. And if unconditioned air is seeping into your home from one location, it only stands to reason that the heated or cooled air you’re paying for is escaping out at some other place. Find and fix any air leaks in these common areas.
- Attics – In the attic, leakage often occurs around dropped ceiling or open stud cavities and attic hatches, and behind knee walls. Seal any holes or leaks with spray foam or caulking in preparation for additional insulation material (see below). Leakage is also common around holes where recessed lighting, vents, ductwork or registers were placed, and should be sealed with a silicone caulk.
- Basements/crawl spaces – Most air leakage occurs in the rim joist cavity, the area along the joists from the foundation to the floor above. Use an expanding spray foam to seal any leaks. Seal any holes where pipes, vents or wiring come in from the outside.
- Doors and windows – Replacing inefficient windows and doors with a more energy-efficient product is the best way to eliminate air leaks. Replacement can be costly, and if that’s not in your budget, you can minimize air leaks by using weatherstripping around openings and installing storm doors and windows. Door and window facings should be re-caulked with a silicone sealant. Don’t forget to check and seal basement windows, as well.
- Baseboards and switch plates – Seal leaks along baseboards and hard floors, as well as around electrical outlets, cable and switch plates.
Insulating Your Living SpaceOnce you’ve sufficiently sealed any air leaks, follow up with an inspection of your home’s insulation. It’s likely your home, when built, was insulated with a minimum to good quality product, but the older your home, the less likely it’s still performing well. Air and moisture may have damaged and compacted the insulation in some areas. More importantly, insulation manufactured today is rated far higher for energy efficiency than older products. For further sealing and insulating the home envelope, check the following areas and add insulation as needed.
- Attics – Insulating the attic is the quickest and most effective fix for sealing and insulating the home envelope. In our area, it’s recommended that 12 to 15 inches of insulation with an R-value of 30 to 60 cover the attic floor. Additional insulation should be placed in any openings, such as dropped ceilings and knee walls.
- Exterior walls – Walls that face an unheated garage or the outdoors should be re-insulated with blow-in insulation if they feel either cold or hot when touched (depending on the season).
- Basements or crawl spaces – Fiberglass batts or other materials that can be damaged by moisture shouldn’t be used in basement or crawl space areas where there’s any possibility of dampness. A rigid foam works well, sprayed along the foundation.