"What is that fan thing you put in the doorway?" is one of the most common questions we get. A blower-door test is the single most objective tool in a real energy audit — here's what actually happens during one.
Step 1: Setup
A calibrated fan is mounted inside a frame that fits your front doorway, sealing the opening. The rest of the home stays as normal — windows and interior doors are typically left in their usual position, with some specific exceptions we'll walk you through.
Step 2: Depressurization
The fan runs, pulling air out of the house and lowering the indoor air pressure relative to outside. As that happens, outside air gets pulled in through every gap, crack, and unsealed penetration in your home's envelope — exactly the leaks we're trying to measure.
Step 3: Measurement
A digital manometer measures the pressure difference between inside and outside, and from that reading we calculate a real, objective number for your home's air leakage — often expressed as air changes per hour (ACH). This is the actual data point, not an estimate.
Step 4: Leak-finding (often combined with thermal imaging)
While the house is depressurized, air is rushing through every leak point at a detectable rate — which makes this the ideal moment to hand-check or thermal-image specific areas (window frames, outlets, attic hatches, recessed lighting) for exact leak locations, not just a whole-house total.
Step 5: Results, explained plainly
You get a real number, not just a subjective "your house seems drafty." That number becomes the baseline for prioritizing air-sealing work, and can be re-tested after sealing work to confirm real, measured improvement — not just a hoped-for one.
What it's not
A blower-door test isn't invasive or damaging — no drilling, no permanent changes. It temporarily changes indoor air pressure for the duration of the test, then everything returns to normal.
Curious what your home's actual number would be? Request a free estimate and we'll schedule a test.
Ready to Find Out Where Your Home Is Losing Energy?
Tell us about your home — we'll schedule a measured, data-driven audit and give you a clear, prioritized report.