24/7 Emergency Response Available — Florida’s humidity doesn’t knock. — Every gap in your building envelope is an open invitation.

SPECIALTY SERVICES

Air Sealing Services

Remediation fixes what went wrong. Air sealing addresses why it keeps happening. Every unsealed gap in your building envelope is a pathway for Florida’s humid outdoor air to enter your structure — driving moisture accumulation, straining your HVAC, and recreating the conditions that produce mold and air quality problems. We find every leak, seal it to building science standards, and verify the results with before-and-after pressure testing.

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OVERVIEW

Your HVAC Is Fighting the Outdoors.
Air Sealing Ends That Fight.

Florida averages outdoor relative humidity between 70 and 90 percent for most of the year. When your building envelope has gaps — and virtually every structure does — that air doesn't stay outside. It infiltrates through attic floors, top plates, HVAC penetrations, recessed light fixtures, plumbing chases, electrical outlets on exterior walls, and dozens of other unsealed transitions. Once inside, it meets your conditioned interior air, cools, and deposits moisture into the building materials surrounding the gap.

This is the mechanism behind a significant portion of the mold and moisture problems we encounter. The remediation addresses the contamination. The air sealing addresses the delivery system that brought the moisture in. Without it, conditions favorable to mold growth are reestablished over time — regardless of how thorough the remediation was.

Air sealing is also the highest-return energy improvement available to most Florida homes. Conditioned air escaping through gaps is the primary reason HVAC systems in this climate run continuously without achieving the target temperature and humidity set points. Sealing the envelope reduces that load directly — and the reduction is measurable with pre- and post-sealing blower door testing.

THE FLORIDA-SPECIFIC CASE FOR AIR SEALING

In cold climates, moisture problems occur when warm interior air escapes and condenses on cold exterior surfaces. In Florida, the dynamic is reversed — hot, humid outdoor air infiltrates and condenses on cooler interior surfaces. Standard building guidance written for northern climates often doesn't account for this. Air sealing in Florida is not just an energy measure. It is a moisture control strategy.

30%

Average HVAC energy loss in Florida homes attributable to air infiltration through the building envelope

ACH50

The metric we measure — air changes per hour at 50 pascals — before and after sealing to verify results

100%

Of our projects include post-sealing pressure test to confirm the work achieved measurable improvement

WHERE LEAKS OCCUR

The Most Common Air Infiltration Points in Florida Structures

Air leaks are not random — they occur predictably at transitions between building materials, mechanical penetrations, and construction details that were never designed with airtightness in mind. These are the locations we target first in every air sealing project.

ATTIC FLOOR PENETRATIONS

Top plates, framing gaps, and any penetration through the ceiling plane — the most significant infiltration pathway in most homes.

RECESSED LIGHT FIXTURES

Unsealed can lights in the ceiling are direct, open-air connections between the attic and the living space below.

HVAC SYSTEM PENETRATIONS

Duct boots, air handler connections, and return plenums in attic or wall cavities are high-leakage points in most systems.

PLUMBING & ELECTRICAL CHASES

Pipe and wire penetrations through the top plate and subfloor are rarely sealed during original construction.

EXTERIOR WALL OUTLETS & SWITCHES

Electrical boxes on exterior-facing walls allow direct air exchange between the wall cavity and the interior.

ATTIC HATCHES & PULL-DOWN STAIRS

Uninsulated and unsealed attic access points are among the largest single-point leaks in the building envelope.

WHAT CHANGES AFTER SEALING

BEFORE AIR SEALING

Humid outdoor air infiltrates continuously through unsealed gaps
HVAC runs longer cycles to compensate for infiltration load
Moisture deposits into framing and insulation around leak points
Conditioned air escapes into unconditioned attic space
Mold conditions reestablish over time despite remediation

AFTER AIR SEALING

Building envelope controls moisture entry at the source
HVAC load reduced — measurable improvement in runtime and efficiency
Moisture deposition at framing and insulation eliminated
Conditioned air stays in the living space where it was intended
Remediation outcomes are sustained — conditions don’t rebuild

OUR PROCESS

How We Approach Air Sealing

1

Blower Door Diagnostic Testing

Before any sealing work begins, we establish a baseline measurement of your building’s air tightness using a blower door test. A calibrated fan is mounted in an exterior doorway and depressurizes the structure to 50 pascals — a standardized pressure used across the industry. The resulting air flow measurement gives us a precise ACH50 figure: how many times per hour the entire volume of the home’s air is replaced by infiltration at that pressure. This number tells us how leaky the building is, and it serves as the baseline against which post-sealing improvement is measured.

2

Thermal Imaging & Leak Mapping

With the building depressurized, we conduct a systematic thermal imaging survey — using an infrared camera to locate where air is moving through the envelope. Infiltrating air changes the surface temperature of surrounding materials, making leak points visible on the thermal image that are invisible to the naked eye. We map every identified leak by location, estimated size, and priority — building a sealing plan that targets the highest-impact points first and ensures no significant pathway is missed.

3

Targeted Air Sealing

Sealing materials and methods are selected based on the specific leak type and location — not a single product applied everywhere. Top plate gaps and framing penetrations in accessible attic spaces are sealed with two-part expanding spray foam, which adheres to irregular surfaces and provides both air and vapor control. Recessed light fixtures are addressed with IC-rated airtight covers or replacement with sealed fixtures. HVAC boot penetrations are sealed with mastic. Plumbing and electrical penetrations are packed and sealed with appropriate materials for the substrate and location. Every product used is specified for the application — materials that perform correctly in Florida’s heat and humidity, not general-purpose products that degrade under those conditions.

4

Ventilation Balance Verification

Air sealing reduces uncontrolled infiltration — but a correctly sealed building still requires controlled ventilation to maintain indoor air quality. Before closing out the sealing phase, we verify that the structure retains adequate mechanical ventilation to meet ASHRAE 62.2 standards for the occupancy load. In homes where ventilation is currently provided entirely by infiltration — a common situation in older Florida construction — we identify whether supplemental mechanical ventilation is needed before the envelope is tightened. Sealing a building without addressing this creates a different set of problems. We document the findings and make specific recommendations.

5

Post-Sealing Blower Door Test & Documentation Report

We repeat the blower door test after all sealing work is complete. The post-sealing ACH50 figure is compared directly against the pre-sealing baseline — giving you a documented, measurable result for the work performed. The final report includes pre- and post-sealing pressure test results, thermal imaging documentation of identified leak locations, a description of all sealing methods and materials used, ventilation assessment findings, and recommendations for any follow-on work. This documentation is useful for energy efficiency incentive programs, insurance purposes, and as a baseline for future building performance assessments.

CLIENT REVIEWS

What Our Clients Say

“We’d had mold remediated twice in three years and kept getting the same result. FPT identified significant air infiltration through our attic floor as the reason moisture kept rebuilding in the space. The air sealing was done right after insulation removal, the before-and-after blower door numbers were impressive, and we haven’t had a recurrence since. Should have done this years ago.”

Michael T.
Homeowner • South Florida

“Our energy bills were significantly higher than neighbors with comparable homes. FPT ran the blower door test and the thermal imaging showed infiltration points we never would have found otherwise. After sealing, our HVAC runtime dropped noticeably within the first billing cycle.”

Sandra L.
Homeowner • Central Florida

FREQUENTLY ASKED QUESTIONS

Common Questions About Air Sealing

What is the difference between air sealing and insulation?

Insulation slows the transfer of heat through building materials — it is a thermal resistance measure. Air sealing stops the physical movement of air through gaps in the building envelope — it is an infiltration control measure. They address different mechanisms and work best when done together. Insulation without air sealing still allows humid outdoor air to bypass the insulation entirely through gaps and penetrations. Air sealing without adequate insulation stops infiltration but doesn’t address conductive heat transfer. In Florida’s climate, air sealing typically delivers the larger immediate benefit because air-transported moisture is the primary driver of both energy load and mold risk.

How do you actually find air leaks?

The blower door test depressurizes the building to a standardized pressure, which amplifies air movement through every gap in the envelope — making leaks detectable that would otherwise be imperceptible. Combined with thermal imaging, which shows the temperature differential created by infiltrating air against surrounding materials, we can locate and map every significant leak point in the structure. This diagnostic approach produces a measurable, documented baseline rather than a visual-only inspection that misses most of what’s actually there.

Can air sealing help prevent mold from coming back after remediation?

Yes — and in many recurring mold cases, it is the missing step. Mold requires moisture. In Florida, the dominant moisture source in many structures is not plumbing failures or roof leaks — it is continuous infiltration of humid outdoor air through an unsealed building envelope. Remediation removes the active contamination. Without addressing the infiltration pathway that delivered the moisture, conditions favorable to mold growth rebuild over time. Air sealing directly reduces the moisture load entering the structure and is one of the most effective ways to sustain remediation outcomes long-term.

Will sealing my home too tightly cause indoor air quality problems?

This is a legitimate concern and one we specifically address in our process. A very tightly sealed home that lacks mechanical ventilation can develop elevated CO₂ levels, VOC buildup, and humidity problems from occupant activity. This is why ventilation balance verification is a formal step in our process — not an afterthought. Before closing out any air sealing project, we confirm that the structure retains adequate controlled ventilation for its occupancy load. Where it doesn’t, we make specific recommendations before the work is considered complete.

How much can air sealing reduce my energy bills?

The reduction depends on how leaky the building was to start with, but in Florida homes with typical infiltration levels, HVAC energy consumption reductions of 15 to 30 percent are common after comprehensive air sealing. The before-and-after blower door test gives you a documented measurement of the improvement achieved — not an estimate. Homes that qualify for utility rebate programs or energy efficiency incentives in Florida can apply the post-sealing test results directly to those applications.

SERVICE AREA

Serving South & Central Florida

FPT Environmental provides air sealing services throughout South and Central Florida — for single-family homes, condominiums, commercial properties, and multi-unit buildings. Air sealing projects can be scheduled as standalone engagements or coordinated with attic insulation removal and other remediation work for maximum efficiency. If you’re unsure whether we serve your area, call us directly — our team will confirm availability and dispatch accordingly.

EXPLORE MORE

More Ways We Can Help

Attic Insulation Removal

Air sealing is most effectively performed immediately after insulation removal — the attic floor is fully exposed and every penetration is accessible. The two services are designed to be done together.

Mold Testing & Remediation

Where air infiltration has already delivered enough moisture to support mold growth, mold testing and remediation addresses the existing contamination before air sealing prevents future recurrence.

Moisture Mapping

Where air sealing diagnostics identify areas of existing moisture accumulation in building materials, moisture mapping documents the full extent of the problem before remediation planning begins.

Specialty Coatings

In attic spaces where structural surfaces were exposed during insulation removal and sealing work, antimicrobial specialty coatings provide a final layer of protection against future microbial growth.

Remediation Fixes the Problem.
Air Sealing Stops It Coming Back.

If moisture keeps returning after remediation, if your HVAC can’t keep up with Florida’s humidity, or if you simply want to address the building envelope before replacing insulation — air sealing is the step most property owners never took. FPT Environmental provides diagnostic-driven air sealing with before-and-after pressure testing across South and Central Florida. The improvement is documented. The results are measurable.