A blower door test is the measured proof of how tight your home is — required for energy code compliance in New York, necessary for HERS ratings and Energy Star certification, and the starting point for any serious energy audit. dL Flow Tech performs residential blower door testing throughout the Hudson Valley and NYC metro. NEBB-certified. BPI-certified. RetroTec equipment. We show up, test the house correctly, and hand you the certified report your builder, rater, or utility program requires.
Schedule a blower door test: Call (845) 265-2828 or request a quote online. We serve Dutchess, Westchester, Orange, Putnam, Rockland, and Ulster counties and NYC.
What is a blower door test?
A blower door test measures the total air leakage of a home's building envelope — all the unintended gaps, cracks, and penetrations where conditioned air leaks out and unconditioned air leaks in. The test uses a calibrated fan temporarily sealed into an exterior door opening. The fan depressurizes the house to a standard 50-Pascal pressure differential, and the airflow required to maintain that pressure is a direct, quantitative measure of total envelope leakage.
Results are reported as:
- CFM50 — cubic feet per minute of airflow at 50 Pascals. The raw measurement.
- ACH50 — air changes per hour at 50 Pascals. CFM50 normalized by house volume; the metric most energy codes use.
- EqLA / EfLA — equivalent leakage area in square inches; useful for comparing leakage to the actual hole size it represents.
The test takes about an hour for a typical single-family home. The report is generated on-site and available immediately after the test.
New York State energy code — blower door test requirements
The New York State Energy Conservation Construction Code (ECCC), based on the International Energy Conservation Code (IECC), requires a blower door test for all new residential construction. The requirement:
- The home must achieve 3.0 ACH50 or less (Climate Zone 5 and 6 — all of New York State).
- Testing must be performed by a qualified third party — not the builder self-certifying.
- Results must be documented and submitted to the building department as part of certificate-of-occupancy documentation.
As an alternative to testing, the IECC allows builders to use the prescriptive air barrier and insulation table — but testing is typically faster, more reliable, and less risky than depending on a checklist that doesn't confirm what was actually built.
New York State blower door test requirements summary
| Requirement | Value |
|---|---|
| Maximum air leakage | 3.0 ACH50 |
| Test pressure | 50 Pascals |
| Climate zone (all NY) | Zone 5 and 6 |
| Testing party | Qualified third party |
| Code | NY ECCC / IECC |
Energy Star and HERS blower door requirements
Energy Star Certified Homes Version 3.2 requires a blower door test with results ≤ 3.0 ACH50 in Climate Zone 5 and above. The test must be performed by a certified HERS Rater or equivalent third-party tester and reported to the RESNET database.
HERS ratings (Home Energy Rating System) incorporate blower door results directly into the energy score. A tighter envelope produces a lower HERS index — better energy performance. Lenders, appraisers, and buyers increasingly use HERS ratings as a proxy for operating costs, and the blower door test is the measurement that sets the infiltration component of the score.
BPI energy audit and blower door testing
BPI (Building Performance Institute) audits use blower door testing as a core diagnostic. In addition to measuring total leakage, the BPI audit protocol uses the blower door to identify where leaks are — by pressurizing the house and then systematically checking areas with a smoke pencil or theatrical smoke to find where air is moving. The BPI audit report is the documentation many utility incentive programs require before authorizing weatherization work.
dL Flow Tech holds BPI certification, and we perform blower door testing for BPI energy audits, utility program qualification, and post-weatherization verification.
Diagnostic blower door testing for existing homes
For homeowners with high heating or cooling bills, drafts, cold spots, or comfort problems that HVAC adjustments haven't fixed, a diagnostic blower door test identifies the envelope leakage that's undermining comfort and driving energy costs.
With the house under depressurization, air rushes in through every leak. A smoke pencil or infrared camera locates where the house is breathing — attic bypasses, rim joist gaps, recessed light fixtures, plumbing penetrations, and window and door air sealing failures. The diagnostic report shows where the sealing work needs to happen, so weatherization contractors know what to address rather than working from guesses.
What blower door test results mean for your home
| ACH50 Result | What It Means | NY Code Compliant? |
|---|---|---|
| ≤ 1.0 | Passive House / extremely tight | Yes |
| 1.0–3.0 | Tight — Energy Star / code compliant | Yes |
| 3.0–5.0 | Average new construction | No (fails ECCC) |
| 5.0–10.0 | Typical existing home | No |
| > 10.0 | Leaky — weatherization priority | No |
How to prepare for a blower door test
Builders and homeowners can take a few steps to ensure the test goes smoothly:
- Close all exterior doors and windows before the technician arrives.
- Close fireplace dampers — and note that fireplaces with open-face dampers are typically bypassed from the leakage measurement per test protocol.
- Confirm the mechanical ventilation system can be turned off — HRVs, ERVs, and exhaust fans are typically shut off or sealed during the test so they don't add to measured leakage.
- Complete drywall and air sealing — blower door tests are performed after the home is dried-in and rough air sealing is complete, but before final paint and trim in many cases.
- Ensure the house is ready for a pressurization test — loose plastic vapor barriers, open attic hatches, and missing cover plates can affect results.
Service area — blower door testing near you
dL Flow Tech performs residential blower door testing across the Hudson Valley and NYC metro: Dutchess, Westchester, Orange, Putnam, Rockland, and Ulster counties, the five boroughs, and surrounding communities from Poughkeepsie to White Plains to Newburgh to Kingston. We are based in Fishkill, NY — centrally located in the Hudson Valley — and schedule residential testing throughout the region.
Ready to schedule a blower door test? Call (845) 265-2828 or request a quote online. We serve the full Hudson Valley and NYC metro.
Frequently asked questions
- What is a blower door test?
- A blower door test measures how airtight a house is. A calibrated fan is temporarily installed in an exterior door opening and depressurizes the house to 50 Pascals. The airflow required to maintain that pressure is a direct measure of total envelope air leakage.
- How much does a blower door test cost?
- Cost depends on house size, location, and test type (code compliance vs. full diagnostic). Contact us for a quote. Most single-family residential blower door tests are completed in one visit.
- What does the blower door test result mean?
- Results are reported as ACH50. New York State ECCC requires new homes to achieve ≤ 3 ACH50. A well-built Energy Star home targets 3 ACH50 or less. Older homes often test at 10–20 ACH50.
- Is a blower door test required for a new home in New York?
- Yes. The New York State Energy Conservation Construction Code requires a blower door test for all new residential construction, confirming ≤ 3 ACH50. Testing must be performed by a qualified third party.
- How long does a blower door test take?
- Setup, testing, and reporting for a typical single-family home takes about one to two hours for a code compliance test. A full diagnostic test with leakage location takes longer.
- How do I find a blower door tester near me in the Hudson Valley?
- dL Flow Tech provides blower door testing throughout the Hudson Valley — Dutchess, Westchester, Orange, Putnam, Rockland, and Ulster counties — and the NYC metro. Call (845) 265-2828 or use our contact form to schedule.
Last updated June 2025