Infiltration
Definition and meaning of Infiltration in real estate.
Infiltration is the unintentional or uncontrolled leaking of outdoor air into a building through cracks, joints, and gaps in the building envelope. This process is driven by wind, temperature differences, and air pressure imbalances between the indoor and outdoor environments.
In more detail
Uncontrolled air infiltration can significantly increase a home's heating and cooling costs, as the HVAC system must work harder to condition the incoming air. It can also introduce moisture, dust, pollen, and outdoor pollutants into the living space, reducing indoor air quality and comfort. Common areas for infiltration include gaps around windows, doors, electrical outlets, and plumbing penetrations.
Home energy auditors use blower door tests to measure a property's infiltration rate and identify specific leaks. Sealing these leaks with caulk, weatherstripping, and insulation is one of the most cost-effective ways to improve home energy efficiency.
Key facts
| Category | Property Types & Construction |
|---|---|
| Common causes | Wind pressure, temperature differentials, and gaps in windows and doors |
| Measurement method | Blower door test conducted by a home energy auditor |
| Remediation | Applying caulk, weatherstripping, and expanding foam sealant |
During a winter home inspection, the inspector uses a thermal camera to locate drafty spots around the baseboards where cold air infiltration is occurring.
Frequently asked questions
How is infiltration different from ventilation?
Infiltration is the accidental, uncontrolled leaking of air into a building, while ventilation is the intentional, controlled exchange of air to improve air quality.
Can a home be sealed too tightly against infiltration?
Yes, a house that is sealed too tightly can trap indoor moisture and pollutants, requiring mechanical ventilation systems to introduce fresh air safely.