Most homeowners are aware that air leaks into their houses through what seems to be small openings around doors and window frames and through fireplaces and chimneys. However, air also enters the living space from other unconditioned parts of the house such as attics, basements, and crawl spaces. The air travels through openings in your walls, floors, and ceilings, particularly where two walls meet, where the walls meet the ceiling and near interior doorframes. Other openings are also typical such as gaps around electrical outlets and switch boxes, recessed fixtures, recessed cabinets, pull-down stairs, furred or false ceilings such as kitchen or bathroom soffits, behind bath tubs and shower stall units, floor cavities of finished attics adjacent to unconditioned attic spaces, and plumbing connections. These leaks between the living space and other parts of the house are often much greater than the obvious leaks around windows and doors.
According to studies, random air leakage can account for as much as 40% of total energy loss. It is not surprising that much more emphasis is now being placed on air leakage control, where payback on investment is far higher than the payback from increasing R-values. In fact, gaps in fiberglass insulation as small as 3% have been found to reduce performance as much as 35%.
Houses leak air because of the difference between indoor and outdoor air pressure. Imagine your house as a hot air balloon. The biggest pressure differences are high and low in the building. Holes in these areas typically leak more air than holes in the middle. Warm air rises and leaks out of any unsealed areas at the top of the building. Leaks inward tend to be at the bottom of the structure, pulling in cold air.
Airtight homes are more economical and comfortable to occupy, if proper ventilation is provided. There are no drafts, only controlled air flows. They are more durable too. In leaky houses, moist, heated air escapes into cooler areas, such as insulated walls and ceilings. There, the vapor condenses which can cause mold, mildew, rot, and other moisture related problems. This is a major source of allergy symptoms.
Spray Foam can potentially reduce air infiltration by more than 90% with just the application alone. There is no need for excess sealing material to acquire the airtight thermal envelope necessary for increased energy efficiency. In one step, it creates a complete insulation and air barrier system to seal all gaps and crevices that compromise air tightness. Its effective air infiltration control allows for HVAC equipment rightsizing for optimal energy efficiency, thereby delivering energy cost savings of up to 50% versus traditional insulation options.
