Insulation alone is not enough. Air sealing stops drafts at the source, slashes energy waste, and makes your insulation work the way it should.
Air sealing is the process of finding and closing the gaps, cracks, and openings in your home's structure that allow conditioned air to escape and outside air to infiltrate. Think of it this way: insulation is like a sweater, and air sealing is like a windbreaker. A sweater keeps you warm on a calm day, but on a windy Oklahoma afternoon, you need that windbreaker to stop the wind from blowing right through the fabric. Your home works the same way.
Even a home with brand-new, perfectly installed insulation will underperform if air is moving freely through gaps in the building envelope. Air leakage is driven by pressure differences created by wind, the stack effect (warm air rising), and your HVAC system. These forces push conditioned air out through every crack and pull unconditioned air in to replace it. The result is wasted energy, uncomfortable rooms, and higher utility bills.
The Department of Energy ranks air sealing as the single most cost-effective energy improvement homeowners can make. For Oklahoma City homes, where temperature extremes swing from over 100 degrees in summer to below 20 degrees in winter, the impact of air sealing is especially significant. Stopping unwanted air movement means your HVAC system runs less, your rooms stay at more consistent temperatures, and you pay less every month on your OG&E bill.
Air leaks are not always where you would expect them. The biggest culprits are often hidden in your attic, not around your windows and doors. Here are the most common air leak locations we find and seal in OKC homes:
Attic bypasses are the single largest source of air leakage in most homes, and they are completely hidden from view. These are openings where the interior walls meet the attic space, allowing heated air from your living areas to flow directly into the attic. Common attic bypasses include open top plates of interior partition walls, gaps around plumbing vent stacks, spaces around chimney chases, and dropped soffits over kitchen cabinets or bathtubs. A single open chase between the wall cavity and attic can leak as much air as leaving a window wide open all year long.
Recessed lighting fixtures that penetrate the attic floor are notorious air leakers. Each non-IC-rated can light creates an opening of roughly 30 square inches that connects your conditioned living space directly to the attic. A home with 15 or 20 recessed lights can have the equivalent of a two-square-foot hole in the ceiling. We seal around each fixture with fire-rated materials that block air flow while maintaining safe clearances for heat.
Every pipe, wire, and duct that passes through a floor, ceiling, or wall creates a potential air leak. Plumbing vent stacks, electrical wire bundles, HVAC supply and return boots, and exhaust fan housings all require sealing where they penetrate the building envelope. These small, individual leaks add up quickly. In a typical OKC home, the combined area of all plumbing and electrical penetrations can equal several square feet of open holes in your attic floor.
The rim joist, where your floor framing sits on top of the foundation wall, is a major source of air infiltration in homes with basements or crawl spaces. This area is often completely uninsulated and unsealed, allowing outside air to pour into the floor cavity and migrate throughout the home. Sealing and insulating rim joists with spray foam is one of the highest-impact air sealing measures we perform.
The attic access hatch or pull-down stair is one of the most overlooked air leaks in any home. Without proper weatherstripping and insulation, the attic hatch is essentially an uninsulated, unsealed hole in your ceiling. Knee walls in bonus rooms, cape cod-style dormers, and finished attic spaces are similarly problematic, often lacking both insulation and an air barrier on the attic side.
Air sealing and insulation are two different things that work together as a system. Insulation resists heat transfer through conduction, slowing the movement of heat through solid materials. Air sealing stops heat transfer through convection, preventing warm or cool air from physically moving through gaps in the building envelope.
When air moves through insulation, it dramatically reduces the insulation's effective R-value. Studies by Oak Ridge National Laboratory have shown that air movement through fiberglass batt insulation can reduce its effective R-value by as much as 50 percent. That means your R-38 attic insulation might only be performing like R-19 if significant air leaks are present underneath it.
This is why Bo's Insulation always recommends air sealing before or during insulation installation. The two services together deliver dramatically better results than either one alone. We frequently perform air sealing as part of attic insulation projects, sealing all accessible bypasses, penetrations, and gaps at the attic floor plane before blowing in new insulation on top.
The energy savings from professional air sealing are substantial and well documented:
A blower door test is the gold standard for measuring how airtight your home is. The test uses a calibrated fan mounted in an exterior doorframe to depressurize your home to a standardized pressure difference. This controlled depressurization exaggerates all air leaks, making them easy to detect by hand or with a smoke pencil, and provides a measurable leakage rate in cubic feet per minute (CFM50).
We use blower door testing in two ways. A pre-work test establishes your home's baseline leakage rate and helps us locate the biggest air leak sites. A post-work test after air sealing is complete verifies the improvement achieved and confirms that the work delivered measurable results. The difference between the two readings tells you exactly how much tighter your home became, and it correlates directly to the energy savings you will see on your utility bills.
Air sealing closes the gaps, cracks, and openings in your home that allow conditioned air to escape and outside air to enter. Even well-insulated homes waste significant energy if air leaks are present, because air movement through insulation dramatically reduces its effectiveness. Air sealing is the single most cost-effective energy upgrade for most homes.
The biggest air leaks are typically in the attic: around plumbing vent stacks, electrical penetrations, recessed lights, attic hatches, chimney chases, and open interior wall top plates (attic bypasses). Other common locations include rim joists, exterior wall outlets, dryer vents, and exhaust fan housings.
Air sealing typically reduces heating and cooling costs by 10 to 20 percent. When combined with proper insulation, total savings reach 25 to 40 percent. Older OKC homes with no previous air sealing work typically see the most dramatic improvements in comfort and energy costs.
A blower door test measures how airtight your home is. A calibrated fan mounted in an exterior door depressurizes the house, making all air leaks easier to detect and quantify. We use blower door testing before and after air sealing work to verify the improvement achieved and confirm measurable results.
Air sealing delivers the best results when combined with other insulation services. Explore our complete offerings:
Combine air sealing with attic insulation for the maximum energy savings your home can achieve.
Learn more →Spray foam insulates and air seals in a single step, ideal for rim joists and crawl spaces.
Learn more →Complete your home's thermal envelope with injection foam wall insulation.
Learn more →A professional energy audit pinpoints exactly where air sealing will have the biggest impact.
Learn more →Get your free estimate today. We will identify your home's biggest air leaks and show you exactly how to fix them.