This is the long version. Every question a builder, contractor or owner-builder has asked us about blower door testing in Florida, answered in one place. Blower door testing is one of four tests that close out a Florida energy permit, and the code compliance page covers how they fit together. If you only need the short answer for a specific city, the blower door testing pages carry a shorter FAQ with your building department named on it.
Table of Contents
When blower door testing in Florida is required
Is a blower door test required in Florida?
Yes. Section R402.4.1.2 of the Florida Building Code, Energy Conservation requires the building thermal envelope of a new residential building to be tested and verified as having an air leakage rate not exceeding 7 air changes per hour at 50 pascals. The test report has to reach the code official before the Certificate of Occupancy is issued.
What is the passing number in Florida?
Generally 7 ACH50 or lower. Florida sits in Climate Zones 1 and 2, and the code sets 7 ACH50 for those zones. Colder climate zones are held to 3 ACH50, which is why numbers you read in national articles often look stricter than what your permit actually requires.
What does ACH50 actually mean?
Air changes per hour at 50 pascals. The fan depressurises the house to 50 pascals, roughly the pressure of a 20 mph wind hitting the building from every direction at once, and measures how much air has to be pulled out to hold it there. That airflow is converted into how many times the entire volume of air inside the house would be replaced in an hour at that pressure. A house at 7 ACH50 is exchanging its full volume of air seven times an hour under test conditions, not under normal ones.
Why 50 pascals, when no house sits at 50 pascals?
Because it is repeatable. At normal conditions, leakage is driven by wind and temperature difference, both of which change hour to hour. Holding the house at a fixed 50 pascals removes the weather from the measurement, so a test in July and a test in January on the same house return the same number.
Which buildings need one?
New residential buildings with conditioned living space. In practice that covers single-family homes, duplexes, townhomes, and apartment and condominium buildings three stories or fewer above grade, which the code treats as residential. Larger multifamily buildings fall under the commercial provisions and are handled differently. Accessory structures and accessory dwelling units (ADU) also require testing if conditioned. This will be structures such as: casitas, guest houses, gyms, offices, etc.
Do additions and renovations need a blower door test?
Sometimes. Section R402.4.1.2 carries a testing exception that can apply to additions, alterations and renovations. Whether it applies to your project depends on the scope and on how your building department reads it, so this is worth a phone call before you assume either way. A remodel that crosses the substantial improvement threshold is a different matter again. That can bring the current energy code with it. Generally, if you were required to submit energy calculations as part of your permit, you’ll need duct leakage testing.
Does adding a mini split to a garage need a blower door test?
More often than people expect, yes. Conditioning a garage with a mini split is permitted work, and when it is permitted the building department will generally want energy and load calculations covering the newly conditioned space. Once those energy calculations are part of the permit, the compliance path behind them carries an air leakage requirement, and that requirement is demonstrated with a blower door test.
So the mini split itself is not really what triggers the testing. The energy calculation the permit requires is. It is worth knowing before the unit goes on the wall, because a garage is usually not built to sit inside a conditioned envelope in the first place. The overhead door alone is a large opening that was never intended to seal like an exterior wall, and it is frequently the reason a newly conditioned garage does not test the way the owner assumed it would.
We provide the energy and load calculations as well as the testing, so both halves of that can come from one place.
Who is allowed to perform the test?
Florida’s test report form limits it to an individual as defined in Section 553.993(5) or (7), Florida Statutes, an individual licensed under Section 489.105(3)(f), (g) or (i), or an approved third party. In plain terms: a certified building energy rater, certain licensed contractors, or an approved independent tester. The signer has to put their license or certification number and issuing authority on the report.
Can the builder test their own house?
Only if they hold one of the qualifications above, and even then some building departments prefer an independent third party. The practical argument for third-party testing is not qualification anyway, it is that the number carries more weight with a plans examiner when the person who measured it does not also own the schedule it affects.
The test itself
How long does a blower door test take?
Most tests take 30 to 60 minutes on site. A straightforward single-family house is usually closer to 30. Larger homes, multiple air handlers or a house that needs a second run after sealing will push it toward an hour.
What standard is the test run to?
ANSI/RESNET/ICC 380. That is the standard named on Florida’s own Envelope Leakage Test Report form, and it governs how the house is prepared, how the fan and manometer are set up, and how the result is calculated. It is the reason two testers on the same house should land within a few percent of each other.
What equipment is used?
A calibrated fan mounted in an adjustable panel that seals into an exterior door opening, and a digital manometer reading pressure inside and out. Calibration matters. An uncalibrated fan produces a number that means nothing, and the calibration date is part of what makes the report defensible.
Is the test destructive? Will it damage anything?
No. Nothing is cut, drilled or opened up. The fan sits in a doorway, runs for a few minutes, and comes out.
What has to be done before the house can be tested?
The building envelope has to be complete and the house has to be in its finished configuration. Windows and exterior doors installed and operable, drywall up, penetrations sealed, insulation in, HVAC installed with registers and grilles on, water traps filled or capped, and the attic access in place. A house tested with a missing window or an unsealed penetration will fail for reasons that have nothing to do with how well it was built.
Does the house need power and water?
Power, yes. The fan needs a working outlet. Water matters because plumbing traps have to be filled or capped, otherwise the fan pulls air straight up the drain line and the reading is increased. If the house is not on permanent power yet, say so when scheduling. We can bring a generator, but we must be notified ahead of time.
Can other trades keep working during the test?
Yes, but they must remain either inside the home our outside the home for the duration of the test. The house has to hold a stable pressure, which means no one opening exterior doors for the few minutes the fan is running. Trades can work through most of the visit; they just need to stay out of the doorways during the measurement.
Does weather affect the result?
No, barring extreme conditions like a hurricane. Test procedure has the tester record a baseline measurement, which is essentially a control group in an experiment. Our meters calculate results around that baseline, to keep test results consistent and repeatable regardless of weather conditions. Excessively high wind speeds can prevent testing, but only on very rare occasions.
Passing, failing, and what the number means
What happens if the house fails?
Air sealing, then a re-test. A failing number is not a code violation on its own. It is a measurement that has to improve before the report can be submitted. What matters is how quickly you find the leaks, which is why a tester who can tell you where the air is going is worth more than one who just hands you a number.
Can a failed blower door test stop the Certificate of Occupancy?
Yes, indirectly. The code requires the report to reach the code official before the CO is issued. No passing report, no report to submit, and final approval waits. That is the entire reason this test sits on the critical path at the end of a job rather than somewhere comfortable in the middle.
How common is failing in Florida?
Uncommon on production work built to a repeated detail, because once a plan passes it tends to keep passing. It shows up more on custom homes, on first builds of a new plan, and on houses where the air barrier was never anyone’s specific responsibility. Florida’s 7 ACH50 is also a more forgiving threshold than the 3 ACH50 used in colder zones, which takes some pressure off.
Where does the air usually leak?
In Florida, most of it is in a short list: the attic plane above the ceiling, top plates, recessed can lights and their trim, bath and kitchen exhaust penetrations, plumbing and wiring penetrations into the attic, the attic access hatch, the garage-to-house wall and its door, and the slab-to-wall junction. Windows and doors get the blame far more often than they deserve.
Is a lower number always better?
For compliance, lower is safer. Beyond that, a tighter house depends more on its mechanical ventilation working properly, because the building is no longer leaking enough to ventilate itself by accident. The lower the number the lower sensible (heat) and latent (humidity) load on the home, meaning a more efficient and comfortable home is achieved at lower scores. That is a design consideration rather than an argument against tightness, and it is why the 2026 code brings mechanical ventilation testing along with it.
Does passing the blower door test mean the house is efficient?
It means the envelope is not leaking more than the code allows. Efficiency also depends on insulation, windows, equipment and duct work. Air leakage is one input into the energy calculation, not the whole of it, which is the distinction between passing a test and meeting a performance target.
Scheduling and reports
When in the build should the test be scheduled?
Once the envelope is complete and the house is close to final inspection, but with enough room left that a failure can be fixed without moving the closing date. Booking it for the same morning as your final is how a two-hour air sealing job becomes a week-long delay.
How far ahead do I need to book?
Next-day scheduling is usually available. The constraint is rarely our calendar. It is whether the house is genuinely ready, and whether your building department needs the report by a particular day to hold a slot.
How fast is the report?
Same day, delivered digitally. The report goes out before we leave the jobsite, so you are not waiting on paperwork to book your final. Our reports are sent directly via email.
What is on the report?
The address and permit information, the conditioned volume used in the calculation, the measured airflow, the resulting ACH50, the standard the test was run to, the equipment and its calibration, and the signature, license or certification number and issuing authority of whoever performed it. That last part is what the plans examiner is checking.
Who submits the report to the building department?
You do. We deliver the signed report to whoever engaged us, whether that is the builder, the contractor or the homeowner, and that party submits it to the building department with the rest of the permit package.
We do not submit on your behalf, and that is deliberate. The permit file belongs to the permit holder. Departments differ in how and where they want documents filed, and a third party dropping paperwork into someone else’s permit is a reliable way to have it land in the wrong place or not get logged at all. You will have the report in hand, signed and ready to hand over, which keeps the chain of custody where it belongs.
Does the test need the energy calculations?
For the envelope test itself, the target is the code number. But if the house is going through the R405 performance path, the energy calculation may set a tighter air leakage target than 7 ACH50, in which case that is the number that matters. Sending the Form R405 or R402 with the booking avoids testing to the wrong target.
What changes in 2026
Is blower door testing going away under the 2026 code?
No. The changes coming with the 9th Edition (2026) do not remove Florida’s building-envelope air leakage testing requirement. What they change is what sits around it: a tighter performance target, duct testing on projects that previously escaped it, and new mechanical ventilation testing.
When does the 2026 code take effect?
The 9th Edition (2026) Florida Building Code is scheduled to become effective December 31, 2026. We have written up the changes that matter most to builders in 2026 Florida Building Code Energy Conservation: What Builders Need to Know.
Still have a question?
If your question is about a specific jurisdiction (who reviews it, how they want the report, what their inspection window looks like) the city and county pages name the authority having jurisdiction for each one. If it is about your project specifically, send us the details and we will answer it directly.
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