Blower Door Test Day in Ocala: What to Expect and How to Prepare Your Site

A blower door test on an Ocala new construction site is a defined, repeatable process. From the technician’s arrival to the signed result in hand, the entire visit takes about 60–90 minutes for a typical single-family home. Builders who understand the process can prepare the site in advance to avoid common delays and ensure the test result reflects the actual envelope performance.

This article walks through what happens on test day at B&I Testing, what site conditions we need, and what builders should do the day before. For the technical background on what’s being measured, see our envelope leakage testing guide.

When to Schedule the Test

The right time to schedule a blower door test for a Marion County certificate of occupancy is after drywall is installed and finished, but before final inspection. Specifically:

• All exterior doors and windows are installed (including the sliding glass door at the rear)
• All drywall is hung, taped, and finished
• All plumbing penetrations through the envelope are in place
• All HVAC ductwork and equipment is installed
• All bath fans, range hoods, and dryer vents are installed
• Recessed lights and ceiling boxes are installed

If the house is at the trim-out / paint-ready stage, it’s ready to test. Testing before drywall gives a wildly inaccurate result because the air barrier (the drywall layer) isn’t in place yet.

Site Preparation: What the House Needs to Look Like

The day before the test, the site supervisor or trim contractor should verify:

All exterior doors closed and latched. Including the garage-to-house door if the garage is unconditioned. The front door, back door, side doors, and any patio doors.

All windows closed and locked. Locked, not just shut — the test creates a pressure differential that can pop unlocked sash windows open.

All interior doors propped open. This includes closets, bedrooms, bathrooms, mechanical closets. The pressure differential needs to equalize throughout the house.

HVAC system off. The thermostat should be set to “Off” — not just changing the setpoint. If the system is running during the test, it interferes with the measurement.

Range hood off. The hood damper should be in its normal closed position.

Bath fans off. Same as range hood — all fans off, dampers in normal closed position.

Fireplace dampers closed. If the home has any fireplaces (wood, gas, or decorative).

Attic access closed. The pull-down stair or hatch should be in its normal closed position with weatherstripping engaged.

Doors to unconditioned spaces closed. Garage doors to outside should be closed. Garage doors to the conditioned interior should also be closed (this is a thermal envelope boundary).

If any of these are out of position when the technician arrives, the test gets delayed while the site is brought to test conditions. Usually 10-15 minutes of setup time.

What the Technician Brings

A standard B&I Testing blower door visit includes:

• The blower door system — a calibrated fan in a fitted nylon panel that fits in an exterior doorway
• Digital manometer — measures the pressure differential between inside and outside
• Reference pressure connections — small tubes that connect the manometer to the indoor and outdoor pressure measurements
• Smoke pencil and infrared camera — for leak finding if the test result is over limit (see our thermal imaging article for how IR finds leaks)
• Test report forms and signature pad — for the final documentation

The equipment is calibrated annually per ANSI/RESNET/ICC 380 requirements. The calibration certificate is part of the test report.

What Happens On-Site, Step by Step

Step 1: Site walk-through (5 minutes). The technician confirms all doors, windows, fans, and HVAC are in test configuration. Any items out of position are corrected.

Step 2: Reference measurements (5 minutes). Outdoor temperature, indoor temperature, wind speed, and barometric pressure are recorded. Conditioned floor area and conditioned volume are confirmed against the plans.

Step 3: Blower door installation (10 minutes). The fan and panel are set up in a designated exterior doorway (typically the front door). The panel is sized to the door opening and sealed against the frame. The pressure tubes are run inside and outside.

Step 4: Baseline pressure check (5 minutes). Before the fan is turned on, the technician checks the natural pressure differential between inside and outside. If wind is high enough to disturb the test, results need correction factors or the test is rescheduled.

Step 5: Depressurization test (10 minutes). The fan is turned on and ramps up until indoor pressure reads exactly -50 Pascals (negative pressure inside, meaning the fan is pulling air out of the house). The fan’s CFM at that pressure is the CFM50 reading. The technician usually takes multiple readings and averages them.

Step 6: ACH50 calculation. CFM50 × 60 ÷ conditioned volume = ACH50. The result is shown on the manometer in real time.

Step 7: Documentation (10 minutes). The result is recorded on the test report along with the project address, date, square footage, conditioned volume, technician name, and test conditions. The builder or site supervisor signs the report.

Step 8: Leak finding (optional, 20-30 minutes). If the result is over 5.0 ACH50, the technician keeps the fan running at -50 Pa and walks the house with smoke pencils to identify the largest leak locations. A leak list is added to the report so the builder’s team knows where to focus sealing efforts. See our article on why Ocala homes fail blower door tests for the patterns we see most often.

What the Test Report Includes

A standard B&I Testing blower door report contains:

• Project information (address, builder, plan number)
• Date and time of test
• Test conditions (outdoor temp, wind, indoor temp)
• Conditioned floor area and volume (used in ACH50 calculation)
• CFM50 result
• ACH50 result
• Pass/fail status against the 5.0 ACH50 Florida code ceiling
• Technician certification information
• Equipment calibration date
• Signature of technician and witness

The report is delivered as a PDF the same day or the next morning. It’s the document that gets submitted with the certificate of occupancy package to Marion County.

If the Test Fails

A failed test at the first attempt is not unusual for new construction, especially when air sealing wasn’t planned as part of the framing strategy. The leak finding pass identifies the major sources, the builder’s team seals those areas, and a re-test confirms the fix.

Re-test scheduling can usually happen within 24-48 hours. Re-test pricing is lower than the initial test because the site is already familiar to the technician.

Most homes pass on the second attempt once the obvious penetrations are sealed. Homes that fail a second test typically have larger envelope issues — wrong insulation type, missing air barrier layer, multiple unsealed penetrations — that need more substantial remediation.

How B&I Testing Schedules Tests in Ocala

B&I Testing operates throughout Marion County. Standard turnaround is:

• Schedule within 3-5 business days of the request
• Test performed in a single visit, 60-90 minutes on-site
• Report delivered same-day or next morning
• Re-test available within 24-48 hours if first test fails

If you need to schedule a blower door test for an Ocala project, call (352) 756-2986, email brandon@banditesting.com, or reach us through the contact form.

Frequently Asked Questions

How long does the test take? 60-90 minutes for a typical single-family home, including site walk-through, setup, the test itself, and documentation. Add 20-30 minutes if leak finding is needed.

Does someone need to be on-site during the test? The builder, site supervisor, or homeowner needs to be present at the start to confirm site conditions and at the end to receive and sign the report. They don’t need to stay for the entire test.

Can you test during rain? Light rain is fine. Heavy rain or thunderstorms postpone the test because we need to keep the equipment dry and the wind speed needs to be moderate for the result to be accurate.

What happens if the wind is too high? We use ANSI/RESNET/ICC 380 wind correction factors when possible. If wind speed is sustained above 15 mph, we may need to reschedule for a calmer day.

Can I be there during the test if I’m a homeowner? Yes — many homeowners want to see the test performed, especially for custom builds. The technician will walk you through what’s happening at each step.