The majority of heat loss or gain is due to conduction of heat through a home's exterior surfaces. The rate of heat transfer depends on the insulation value of that surface and the temperature difference between inside and outside that surface.
It's important to realize that heat will move through EVERY building surface. The old saying "heat rises" is a partial truth...warm air rises but heat conducts through materials from hot to cold in any direction. This means that simply adding more attic insulation is not going be a magic bullet when it comes to saving energy or improving comfort.
Attics - Attic often get better insulated then walls, floor perimeters, foundations and basement floors. This makes sense because attics are usually the most cost effective places to add insulation and because it helps keep homes cool when attics get very hot in summer.
Exterior Walls - Up until the mid-1900s many walls were partially or completely uninsulated. If you have an older home, your wall cavities may need more insulation. We scan walls with an infrared camera and probe cavities to determine if they need insulation. If so, there are a number of ways we can access and dense-pack them with cellulose insulation.
Band Joists - A band joist is the exterior perimeter of a second story floor platform and is commonly uninsulated in older homes. Finished first floor ceilings make band joists difficult to access. However, if there is a lot air leakage through the band joist (perhaps to a porch roof) or if your exterior walls need insulating anyway it can be cost effective to insulate band joists.
Sill Boxes - A sill box is the exterior perimeter of a first story floor platform where it rests on the foundation. Accessible sill box cavities are most cost effectively insulated with fiberglass batts although 2-part spray foam may also make sense if there is significant air leakage, moisture damage, or pest infiltration.
Overhangs/Cantilevers - In some homes, part of the band joist may overhang past the first floor walls or the sill box may overhang past the foundation. Insulation should fill the entire volume of the overhang to prevent comfort problems, moisture damage and degraded insulation value due to convection. This is also true for floors that cantilever over garage ceilings.
Foundations - Foundation walls have a lot of surface area and very little insulation value. We insulate poured concrete or cement block walls on the interior with foil faced Thermax insulation or on the exterior with foam board covered with a durable finish.
Basement Slabs - While basement slabs have similar surface area to attic floors, they do not experience as much energy loss since the soil maintains an average temperature of about 55 degrees. However, they can still feel uncomfortably cold in winter. If your basement stays dry, we can improve your slab insulation with a floating floor using foam board and T&G plywood.