Air Sealing in Boulder, CO
Sealing the hidden leaks that waste heat and cause drafts — the highest-return first step before adding insulation.
Insulation slows heat, but it doesn't stop air. If your Boulder home is leaky — and most are — warm air escapes through hundreds of small gaps around the clock, dragging cold outdoor air in behind it. Air sealing finds and closes those leaks, and it's almost always the highest-return efficiency work you can do. Done before an insulation upgrade, it makes every dollar of new R-value actually perform.
From the attic top plates and can lights to rim joists, plumbing and wiring penetrations, ductwork, and the attic hatch, we methodically seal the pathways that let your conditioned air leak away. The result is fewer drafts, steadier temperatures room to room, lower bills, and a healthier home.
Why homeowners choose it
- Stops the drafts and cold spots insulation alone can't
- Makes new insulation perform to its full R-value
- Lowers heating and cooling bills, often significantly
- Reduces dust, pollen, and wildfire-smoke infiltration
- Helps prevent ice dams by cutting attic heat loss
- Improves indoor comfort and humidity stability
Where homes leak — and what we seal
Air leaks hide in predictable places, and they add up to the equivalent of leaving a window open year-round. The biggest culprits are up high and down low, where the 'stack effect' drives warm air out the top of the house and pulls cold air in at the bottom. We target the whole set: attic top plates, recessed lights, plumbing and wiring penetrations, the attic access hatch, rim joists in the basement, band joists, duct connections, and gaps around windows and doors.
Using caulk, foam, gaskets, and weatherstripping matched to each location, we close these pathways so your heating and cooling stays inside where you paid to put it.
- Attic top plates, penetrations, and recessed lights
- Attic hatch and knee-wall gaps
- Basement rim and band joists
- Duct connections and register boots
- Window, door, and sill leaks
Why air sealing comes before insulation
It's tempting to just pile on more insulation, but insulation laid over a leaky attic floor underperforms because air moves right through and around it. Sealing the leaks first means the new insulation you add actually delivers its rated R-value. That's why we treat air sealing as step one of any attic or wall upgrade — it's the cheapest, highest-ROI work in the whole project, and it multiplies the value of everything that follows.
Measured results with blower-door testing
Air sealing is most effective when it's measured, not guessed. A blower-door test depressurizes the home so we can quantify how leaky it is and pinpoint exactly where the air is moving, and a follow-up test confirms the improvement. This diagnostic approach — part of our energy-audit service — turns air sealing from a hopeful effort into a verifiable result, and provides the documentation that Xcel rebate programs often require.
Ideal for
- Drafty homes with cold or hot rooms
- Any home about to add attic or wall insulation
- Older Boulder County houses that were never sealed
- Homes with high winter heating bills
- Anyone concerned about dust or outdoor air quality
What affects the cost
Air Sealing questions, answered
It's often the single best-value efficiency improvement a home can make. Air leaks can waste as much energy as a window left open all year. Sealing them costs far less than a major insulation project and delivers immediate comfort gains — and it makes any insulation you add afterward perform to its full rating.
Yes — always seal first. Insulation slows heat but doesn't stop air movement, so adding it over unsealed leaks underdelivers. Sealing the attic floor and other pathways first ensures your new insulation reaches its rated R-value. We treat air sealing as step one of any attic or wall upgrade.
It's a diagnostic that uses a calibrated fan mounted in an exterior door to depressurize your home, revealing how much air it leaks and exactly where. We use it to target sealing work and to verify the improvement afterward. It's part of our energy-audit service and provides documentation many rebate programs require.
Yes. A tighter envelope means less unfiltered outdoor air — and the dust, pollen, and wildfire smoke it carries — infiltrating your living space. Combined with good filtration, air sealing noticeably improves indoor air quality, which matters a lot along the Front Range.
Air Sealing done right, by a local Boulder crew
Air Sealing isn't a commodity — the result depends entirely on how carefully it's planned and installed for your specific home and Colorado's climate. We assess what your house actually needs, prep and air-seal properly, and install to your target R-value, so the work delivers the comfort and savings it's supposed to. No shortcuts, no builder-grade rush.
We serve Boulder, Longmont, Louisville, Lafayette, Superior, Niwot, Nederland, and the rest of Boulder County, and we'll help you capture the Xcel and local rebates that bring your project cost down. Every job starts with a free, no-pressure quote.
Just as important, we treat your home like the system it is. Insulation, air sealing, ventilation, and moisture control all interact, and getting one right while ignoring the others leaves comfort and savings on the table. When we scope your air sealing, we look at how it fits the whole picture — so the finished result performs the way it should, holds up through Colorado winters, and actually lowers the bills you feel every month. That whole-home mindset, plus honest advice about what your house truly needs, is what our neighbors across Boulder County count on us for.
Free assessment
We evaluate your home and give you a clear, itemized quote with rebates factored in.
Expert install
We prep, air seal, and install your air sealing to spec — clean and on schedule.
Savings you can feel
A more comfortable home, lower bills, and help claiming every rebate you qualify for.
Related services
Ready for a free air sealing quote?
Tell us about your home and we'll put together a clear, no-pressure quote — plus show you which Xcel rebates you qualify for.