Air Sealing: The Fastest Way to Cut Energy Bills
Older homes in Mt Prospect and the surrounding Chicago suburbs weren't built tight. Gaps around pipes, electrical boxes, and attic hatches let conditioned air escape year-round. Air sealing closes those gaps. It's one of the least glamorous upgrades you can make, and one of the most effective at cutting your monthly utility bills.
Why Older Homes Leak So Much Air
Most homes built before the 1980s were constructed before modern energy codes existed. Builders didn't worry much about air barriers. Framing gaps got covered by drywall, but nothing sealed the spaces where wires, pipes, and ducts punched through.
Over decades, wood framing shrinks and shifts. Caulk dries out. Foundation sills separate from the framing above them. Every one of those gaps becomes a channel for outside air to enter and inside air to escape. In Chicago winters, that means your furnace runs longer than it should to keep up.
A typical older home in the area can have the equivalent of a one- to two-square-foot hole in the building envelope when you add up all those small gaps. That's a lot of wasted heat.
Where the Biggest Leaks Hide
Most homeowners assume windows and doors are the main problem. They're visible and easy to feel on a cold day. But windows and doors are actually a smaller part of the total air leakage in most older homes.
The real culprits tend to be in spots you rarely see:
- The band joist, where the floor framing meets the foundation wall
- Attic bypasses, which are gaps where interior walls meet the attic floor
- Around recessed light cans that penetrate the ceiling into an unconditioned attic
- Plumbing and electrical penetrations through top plates and floors
- The attic hatch, which is often uninsulated and unsealed
Fixing these spots gives you far more return than re-caulking window frames. A blower door test can measure exactly how leaky a house is and help pinpoint where the work needs to happen.
What Air Sealing Actually Involves
Air sealing isn't one product. It's a combination of materials applied in the right spots. Spray foam works well for larger gaps and penetrations. Caulk handles smaller cracks. Rigid foam board with tape or foam at the edges works for band joists and attic hatches.
In the attic, a contractor seals all the bypasses before adding or upgrading insulation. Sealing first matters. If you just pile on more insulation without sealing, air still moves through the insulation and carries heat with it. The insulation barely helps.
Our air sealing and insulation work often pairs with other projects. When a basement finishing job is underway, for example, the band joist is exposed and easy to seal. That's the right time to do it.
How Much Can You Actually Save
The numbers vary by house, but the U.S. Department of Energy estimates that air sealing combined with insulation upgrades can reduce heating and cooling costs by 10 to 20 percent in a typical home. For an older drafty house in the Chicago area, savings at the higher end of that range are common.
The payback period on air sealing work is usually shorter than most other energy upgrades. New windows, by comparison, often take 20 or more years to pay back through energy savings alone. Air sealing on the band joist and attic can pay back in two to five years.
Illinois also has utility rebate programs through ComEd and Nicor Gas that can offset part of the cost. A contractor familiar with those programs can help you document the work correctly to qualify.
Air Sealing During a Remodel Makes Sense
The best time to air seal is when walls, ceilings, or floors are already open for another reason. A whole home remodeling project gives access to framing bays and top plates that are impossible to reach otherwise. Adding air sealing to the scope costs far less than coming back later when everything is buttoned up.
Window and door installation is another natural opportunity. When old units come out, the rough opening is exposed. Proper sealing at that stage keeps drafts out for the life of the new window instead of relying on exterior caulk that weathers and cracks.
If you're planning any work on your Mt Prospect home, it's worth asking your contractor to look at air sealing at the same time. The marginal cost is low and the long-term benefit is real.
If your heating bills seem high for the size of your home, air leakage is a good place to start looking. B&C Remodeling handles air sealing and insulation work across Mt Prospect and the surrounding area. Give us a call and we'll take a look at what your home actually needs.