RESNET Certified Inspector | Measured Airflow, Not Nameplate | Immediate Electronic Reports
What Is Mechanical Ventilation Testing?
Florida requires whole house mechanical ventilation in any dwelling unit that tests tighter than 3 air changes per hour at 50 pascals. Mechanical ventilation testing measures what the installed system actually delivers and compares it against the rate the home is required to receive. It is the same idea as a blower door test turned around, measuring the air coming in rather than the air leaking out, and it has quietly become the thing builders are least prepared for now that envelopes have gotten good.
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Why This Became Everyone’s Problem at Once
For years the ventilation requirement was mostly theoretical in Florida, because houses did not test tight enough to trigger it. That has changed. Spray foam, better air sealing and crews who seal the ceiling plane properly now routinely land homes between 1.5 and 3.0 ACH50. The moment the blower door reads under 3.00, whole house mechanical ventilation is required. The trigger is not a design decision anyone makes, it is a test result, which means it can land on a house nobody planned for it.
What We Verify
Testing a ventilation system means measuring the airflow actually delivered into the house and confirming the system runs the way the design assumed.
What we check:
The gap we find most often is not a missing system. It is a system that was installed, wired and forgotten, delivering a fraction of its rated airflow through undersized flex, a damper that never opens, or a control nobody commissioned. Nameplate capacity is not delivered airflow, and only the measurement tells you which one you have.
How We Keep Our Services Simple and Easy
We want ventilation verification to fit the schedule you already have.
1.
Tell us about the project
Send the plan, the energy calculation and the ventilation design if one exists. If the blower door result is already in hand, send that too.
2.
onsite measurement
We measure delivered airflow at the ventilation inlet, and at any local exhaust in the scope, with the system operating the way it will in service.
3.
Comparison Against the Required Rate
We put the measured number next to the rate the dwelling is required to receive, so what you get back is a pass or a specific shortfall rather than a raw reading.
4.
Report delivered by email
Measured airflow, required rate, equipment and configuration, delivered the same way as every other report we issue.
5.
A clear path if it comes up short
If the airflow misses, we tell you what is causing it, whether that is duct run, damper, control or equipment selection, so the fix goes to the trade that owns it.
Tightened the House? Now Prove the Air Is Coming In.
Why Builders Choose Stellar Building Performance
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Other Areas We Serve
Mechanical ventilation testing, blower door testing and duct leakage testing throughout Brevard, Indian River, St. Lucie, Martin and Okeechobee Counties.
Recent Projects in Your Area
Ventilation verification usually rides along with blower door testing on the same visit, so it shows up inside our blower door project updates rather than as a category of its own.
Frequently asked questions about mechanical ventilation testing
In Florida, when the dwelling unit tests at less than 3.00 air changes per hour at 50 pascals. Section R303.4 of the Florida Residential Code and Section R402.4.1.2 of the Florida Energy Conservation Code both carry that requirement. Worth knowing that this is a Florida specific number. Most of the country uses 5 ACH50, so national guidance and out of state trades will often tell you something different.
That is the situation we run into most often, and it is solvable, but it is far cheaper to solve before final inspection than after. The fix is a ventilation system sized and controlled for the required rate, and there are several accepted ways to get there.
The usual paths:
What we see go wrong:
It is a function of the home’s conditioned floor area and the number of bedrooms. That calculation belongs with the mechanical design and is usually already sitting in the energy documentation or the Manual J submittal. Send it with the booking and we test against your project’s number. If it does not exist yet, that is a conversation worth having before equipment gets ordered.
Yes, and that is how most of our jobs run. The blower door result is what determines whether ventilation is required in the first place, so one party doing both means you find out and verify on the same trip instead of scheduling a second visit after the number comes back.
Sometimes, but only if it is rated for continuous duty, sized for the required rate, controlled appropriately and actually delivering that airflow. A standard intermittent bath fan on a wall switch is not a whole house ventilation system, though it gets drawn as one on plans fairly often. The measurement settles it.
No. The blower door test is run with the ventilation system sealed or shut off, per the test standard, so a properly installed system does not change your leakage result. What it changes is whether that leakage result is allowed to stand on its own.
Mechanical Ventilation Reference
How Whole House Ventilation Fits Florida Code Compliance
Ventilation is the requirement your blower door result creates. Below 3.00 ACH50 it applies, and it is verified by measuring delivered airflow rather than by reading a label. These are the code lines the requirement comes from.
questions? give us a call, this is our specialty!
BIG CHANGES COMING IN 2026 FLORIDA BUILDING CODE UPDATES
Duct Leakage testing to be required on all homes with few exceptions, more stringent compliance targets, mechanical ventilation testing & more. Read our updates bulletin below.
2026 Florida Building Code Energy Conservation: What Builders Need to Know
This is the line that connects your blower door result to a ventilation requirement. A dwelling unit with a measured air leakage rate below three air changes per hour must be provided with whole house mechanical ventilation. The parallel requirement sits at Section R303.4 of the Florida Residential Code, and the system itself is designed to Section M1507.3 of the Florida Building Code.
R402.4.1.2 Testing.
The building or dwelling unit shall be tested and verified as having an air leakage rate not exceeding seven air changes per hour in Climate Zones 1 and 2, and three air changes per hour in Climate Zones 3 through 8. Dwelling units with an air leakage rate less than three air changes per hour shall be provided with whole-house mechanical ventilation in accordance with Section R403.6.1 of this code and Section M1507.3 of the Florida Building Code, Residential. Testing shall be conducted in accordance with ANSI/RESNET/ICC 380 and reported at a pressure of 0.2 inch w.g. (50 pascals). Testing shall be conducted by either individuals as defined in Section 553.993(5) or (7), Florida Statutes, or individuals licensed as set forth in Section 489.105(3)(f), (g) or (i) or an approved third party. A written report of the results of the test shall be signed by the party conducting the test and provided to the code official. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope.
Exception: Testing is not required for additions, alterations, renovations or repairs of the building thermal envelope of existing buildings in which the new construction is less than 85 percent of the building thermal envelope.
During testing:
1.Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed, beyond the intended weatherstripping or other infiltration control measures.
2.Dampers including exhaust, intake, makeup air, backdraft and flue dampers shall be closed, but not sealed beyond intended infiltration control measures.
3.Interior doors, if installed at the time of the test, shall be open.
4.Exterior doors for continuous ventilation systems and heat recovery ventilators shall be closed and sealed.
5.Heating and cooling systems, if installed at the time of the test, shall be turned off.
6.Supply and return registers, if installed at the time of the test, shall be fully open.
7.If an attic is both air sealed and insulated at the roof deck, interior access doors and hatches between the conditioned space volume and the attic shall be opened during the test and the volume of the attic shall be added to the conditioned space volume for purposes of reporting an infiltration volume and calculating the air leakage of the home.
On the performance path, the air leakage rate your energy calculation assumed becomes the number the house has to hit. If that modeled rate is below 3.00 ACH50, the project has committed itself to mechanical ventilation whether or not anyone said so out loud. This is worth checking at permit rather than at final.
R405.2.2 Building air leakage testing.
Building or dwelling air leakage testing shall be in accordance with Sections R402.4 through R402.4.1.2. If an air leakage rate below seven air changes per hour at a pressure of 0.2 inch w.g. (50 pascals) is specified for the proposed design, testing shall verify the air leakage rate does not exceed the air leakage rate of the proposed design instead of seven air changes per hour.
Ventilation ducts are ducts. An outdoor air duct running through an unconditioned attic carries the same installation and sealing expectations as the rest of the system, and a leaky, kinked or undersized outdoor air run is one of the most common reasons measured airflow lands under the required rate.
R403.3.3 Duct testing (Mandatory).
Ducts shall be pressure tested to determine air leakage by one of the following methods:
1.Rough-in test: Total leakage shall be measured with a pressure differential of 0.1 inch w.g. (25 Pa) across the system, including the manufacturer’s air handler enclosure if installed at the time of the test. All registers shall be taped or otherwise sealed during the test.
2.Postconstruction test: Total leakage shall be measured with a pressure differential of 0.1 inch w.g. (25 Pa) across the entire system, including the manufacturer’s air handler enclosure. Registers shall be taped or otherwise sealed during the test.
Exceptions:
1.A duct air leakage test shall not be required where the ducts and air handlers are located entirely within the building thermal envelope.
2.Duct testing is not mandatory for buildings complying by Section R405 of this code. Duct leakage testing is required for Section R405 compliance where credit is taken for leakage, and a duct air leakage Qn to the outside of less than 0.080 (where Qn = duct leakage to the outside in cfm per 100 square feet of conditioned floor area tested at 25 Pascals) is indicated in the compliance report for the proposed design.
A written report of the results of the test shall be signed by the party conducting the test and provided to the code official.
R405.2.3 Duct air leakage testing.
In cases where duct air leakage lower than the default Qn to outside of 0.080 (where Qn = duct leakage to the outside in cfm per 100 square feet of conditioned floor area tested at 25 Pascals) is specified for the proposed design, testing in accordance with Section R403.3.2 shall verify a duct air leakage rate not exceeding the leakage rate of the proposed design. Otherwise, in accordance with Section R403.3.3, duct testing is not mandatory for buildings complying by Section R405.
The code sets a minimum efficacy for the fan serving a whole house ventilation system, expressed in cubic feet per minute per watt. It matters because it rules out solving the requirement with whatever fan is cheapest on the shelf. Equipment selection, duct sizing and the measured result are all one conversation.
R403.6.1 Whole-house mechanical ventilation system fan efficacy.
When installed to function as a whole-house mechanical ventilation system, fans shall meet the efficacy requirements of Table R403.6.1.
Exception: Where an air handler that is integral to tested and listed HVAC equipment is used to provide whole-house mechanical ventilation, the air handler shall be powered by an electronically commutated motor.
Review TABLE R403.6.1 WHOLE-HOUSE MECHANICAL VENTILATION SYSTEM FAN EFFICACY
R403.6.2 Ventilation air.
Residential buildings designed to be operated at a positive indoor pressure or for mechanical ventilation shall meet the following criteria:
1.The design air change per hour minimums for residential buildings in ASHRAE 62.2, Ventilation for Acceptable Indoor Air Quality, shall be the maximum rates allowed for residential applications.
2.No ventilation or air-conditioning system make-up air shall be provided to conditioned space from attics, crawlspaces, attached enclosed garages or outdoor spaces adjacent to swimming pools or spas.
3.If ventilation air is drawn from enclosed space(s), then the walls of the space(s) from which air is drawn shall be insulated to a minimum of R-11 and the ceiling shall be insulated to a minimum of R-19, space permitting, or R-10 otherwise.
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Similar Services
Stellar Building Performance specializes in building performance diagnostics.
Duct Leakage Testing
Verify duct system airtightness using professional duct leakage testing required for new construction inspections.
Blower Door Testing
Measure whole house air leakage against the Florida energy code threshold. It is also the test that determines whether your project requires mechanical ventilation at all.
Helping Builders Stay on Schedule and Pass Inspections
Fast Scheduling
Builders get testing scheduled quickly to avoid delays.
accurate results
Professional equipment ensures reliable measurements.
immediate reports
Documentation provided immediately by email for inspection approvals.
