Blower Door Testing: Compare Preparation, Measurements, and Follow-Up

Pay for a measured test when you need to know how leaky the home is, not just where a draft feels. The Department of Energy says a calibrated blower door uses a fan and pressure gauge to measure airflow and airtightness; a fan that only moves air can locate leaks without measuring their amount (DOE Consumer Guide to Home Energy Assessments). Compare quotes by the data and safety process included, because “blower-door visit” can mean a full assessment or a quick demonstration.

Use this test-card:

Quote line	Confirm before booking	Why it matters
Equipment	Calibrated fan, manometer, software and test standard	Produces a measurement that can be compared over time
Conditions	Weather, doors, windows, vents, HVAC and combustion setup	Test conditions affect interpretation and safety
Safety	Combustion-appliance checks and stop criteria	Depressurization can expose unsafe conditions
Outputs	Leakage metric, photos, leak locations and assumptions	Turns a number into a repair plan
Follow-up	Duct test, air-sealing visit or verification test	Separates diagnosis from construction and proof

Ask whether the provider will report the leakage metric, pressure used, fan flow, indoor and outdoor conditions, house volume assumption, and any applicable rating or program requirement. DOE’s retrofit guidance describes a calibrated blower door as a way to measure overall house leakage and an infrared camera as a way to show temperature differences that can indicate leaks (DOE retrofit techniques). A result without units, conditions, or a stated method is difficult to compare with another test. Ask for a diagram or photo index showing locations rather than a generic “air leaks found” sentence.

Safety is a quote variable. The DOE guide says an assessor may inspect heating and cooling systems, check ventilation, and test natural-gas leaks. A test can reveal safety problems that must be corrected before air sealing. Ask whether the provider includes combustion-safety screening or refers it to a qualified technician. Do not close combustion openings, adjust appliances, or seal penetrations around fuel-burning equipment yourself.

Preparation should be written, not guessed. Ask the assessor what to do with fireplace dampers, woodstoves, exhaust fans, interior doors, pets, and occupants. Record anything the provider cannot control, such as a shared wall or an inaccessible attic. A test of one unit in a multi-unit building may include leakage paths outside that unit; confirm the boundary before comparing results.

The number is a diagnostic input, not a guaranteed bill reduction. DOE says the assessment report should provide findings and improvement ideas, while the owner decides which upgrades to make. Air sealing, insulation, duct repair, ventilation, and HVAC work can require different scopes. Use attic insulation cost when the assessment points to insulation work, and keep the test, repair, and verification fees separate.

Ask two providers for proposals using the same property details and output requirements. Include address, conditioned floor area, stories, fuel systems, known comfort complaints, and whether you need a code, rebate, or retrofit metric. Compare travel, test, safety check, report, leak-location mapping, duct test, repair, and retest lines. The better quote is the one that gives a reproducible measurement, states conditions and limits, and explains what action the result can support.