Blower Door Testing and Thermal Imaging for Homes

A blower door uses a calibrated fan and pressure measurements to quantify how much air leaks through the home. Results are commonly reported at a 50 pascal pressure difference, using units such as air changes per hour or air permeability, which is the leakage rate for each square metre of the tested shell.

Thermal imaging shows surface-temperature differences. It can help identify patterns consistent with missing or displaced insulation, thermal bridging, damp areas or air leakage, but the image does not prove the cause on its own.

• Measure the home before and after planned air-sealing work.
• Check a new building envelope before finishes make defects harder to reach.
• Investigate widespread draughts or comfort problems when visual checks are not enough.
• Record the test method, building configuration, equipment and result units so a later test can be compared fairly.

• Look for insulation gaps, compression or displacement in ceilings and walls.
• Check repeating patterns that may show a thermal bridge, where framing or another path carries heat around the insulation.
• Inspect around windows, doors, downlights, exhaust fans and service penetrations.
• Record paired visible and thermal images, the location, indoor and outdoor conditions, camera details and any limitations.

A blower door can create a controlled pressure difference while a practitioner uses a thermal camera or smoke tool to trace likely leakage paths. The combined evidence is useful when preparing a targeted sealing or insulation scope and when checking the result after work.

For a straightforward visible defect, one tool may be enough. Ask what decision the test needs to support before paying for a larger scope.

• Do not block intentional ventilation, exhaust paths, flues or combustion-air openings.
• Record gas, wood and other combustion appliances before pressure testing or permanent sealing work.
• Investigate moisture, condensation and mould before closing a building assembly or reducing its drying path.
• Plan adequate kitchen, bathroom, laundry and whole-home ventilation as airtightness improves.
• Use the licences and specialists required for any electrical, gas, building, moisture or hazardous-material work found during the assessment.

• The purpose of the test and whether it covers the whole home or a defined area.
• The test method, practitioner capability and current equipment or calibration details.
• The building setup, weather and operating conditions that will be recorded.
• A clear report with results, labelled evidence, limitations and recommended next checks.
• Whether a follow-up test after repairs is included or separately priced.