air leaks and air sealing basics
Air leaks alone can account for large energy bills. And they are also a major cause of discomfort, moisture problems and even unhealthy air.
Air leakage sources
Stopping air leaks in windows and doors (or around them) by caulking and weather-stripping, or by installing storm windows, is important but not enough. There are many other important sources of air leakage - often more important than the visible and known ones around windows and doors.
The image at right, from DOE, shows the importance of the several air leaks in an average home.
See:
Around Windows and Doors Air Sealing
Air Sealing Soffits/Dropping Ceilings
Air Sealing Electrical and Ventilation Openings
Air Sealing Attic Penetrations
Air Sealing Bath Tubs and Plumbing Penetrations
Air Sealing Fireplaces and Chimney Openings
Air Sealing Knee Walls
Air Sealing Exterior Joints and Top and Bottom Plates
Tests and how to make an air leakage diagnosis
You can carry out yourself some easy tests to identify air leakage. But you may need or want a professional energy audit to your home, involving insulation and air leakage.
See: Home Audit Basics
Types of air leaks and where to look for them
People are much more aware of small openings and cracks around doors and windows, fireplaces or chimneys, than of infiltration and air escaping associated with the attic, crawlspaces, or ducts and plumbing... But these are - in most cases - the major problem.
See:
Where to look for Air Leaks
Air Sealing vs. Insulation
Air Sealing Materials
Caulking materials
Applying Caulks
Air Sealing Foams and their Application
Weatherstripping basics
Ventilation
In most climates and situations, relying on air leakage for ventilation isn’t wise. You will get too much cold air during bad weather conditions or too less in hot and non-windy conditions.
The recommended strategy is to reduce air leakage as much as possible, and to use natural and mechanical ventilation to get fresh air.
See: Ventilation, Air Leaking and Healthy Indoor Air
Moisture problems
Air infiltration contributes to problems with moisture and dusty air. These can easily enter a leaky house through attics, foundations or walls...
Air Sealing New homes
You may avoid air leakage problems by doing it rightly the first time, that is, when building a new home. Many structural air leaks are due to constructions flaws.
If building a new home, take into account the air barriers issue. The home's shell (floor and foundations, walls and ceiling) should benefit from a continuous air barrier...