Air sealing and ventilation: questions to ask before the work

Separate uncontrolled leaks from planned ventilation

A draft through a gap is not a reliable ventilation strategy. The U.S. Department of Energy says an air-sealing project should begin by considering how much fresh air is needed for healthy indoor air and for combustion appliances. Ask the assessor which leaks are targets, which ventilation systems already exist and whether the proposed work changes how those systems operate.

Identify moisture and pollutant sources

The U.S. Environmental Protection Agency recommends controlling pollutant sources and using appropriate ventilation. Note persistent condensation, water damage, musty areas, cooking exhaust and bathroom exhaust. Do not seal over an unexplained leak or moisture problem. Ask whether exhaust fans vent outdoors, whether they work, and which conditions require a qualified inspection.

Protect combustion safety

Fuel-burning heaters, water heaters, stoves and fireplaces can create harmful combustion products if they are installed or vented improperly. EPA notes that pressure changes during remodeling can contribute to backdrafting in some systems. Ask a qualified professional whether combustion appliances, venting and carbon monoxide protection need checks before and after air sealing. Do not block a vent or modify equipment yourself.

Put verification in the scope of work

Request written locations to be sealed, materials, safety checks, ventilation recommendations and how results will be verified. An assessor may use diagnostics, but the right tests depend on the house. Compare the completed scope with the proposal and keep records. A lower energy bill is possible in some homes, but this guide cannot predict savings or certify indoor air quality for yours.

• Which gaps will be sealed, and why?
• What ventilation is currently provided?
• Who checks moisture and combustion appliances?
• What is included in post-work verification?