Air sealing for your attic, doors, and windows
We identify and seal accessible air-leakage pathways throughout the building envelope—starting at the attic floor, then major chases, wall and ceiling connections, doors, windows, and other applicable openings—so insulation can do its job.
Get a free estimateFree estimates. A written price before work starts.
Air sealing locations and scope of work
Not to scale
- 1Attic hatch: weatherstripped, with an insulated cover
- 2Ceiling gap around each duct boot
- 3Plumbing vent and wiring through the top plate
- 4Top plates of interior and exterior walls
- 5Recessed lights rated for insulation contact (IC), sealed at the trim
- 6Bath fan housing sealed to the ceiling
- 7Dropped soffit or open framing capped with rigid board
- 8Flue/chimney penetrations: air-sealed with approved fire-safe materials while maintaining required clearances; no equipment modifications.
- 9Doors: weatherstripping and a door sweep
- 10Windows: caulked at the frame
- 11Large plumbing or HVAC chases blocked and sealed
- 12Rim joists and floor-to-foundation connections, where accessible
- 13Exterior wall penetrations for utilities, hose bibs, and wiring
- 14Kneewalls or other attic transitions, where applicable
Seal first
Every major gap, hole, and penetration is sealed before insulation goes in, with the material matched to the opening.
Whole-envelope scope
Scope may include attic penetrations, chases, rim or sill connections, exterior wall penetrations, and other accessible leakage paths.
Then insulated
The sealed attic floor is covered with insulation to the R-value on your quote. Locations vary by house and access.
Representative sealing locations shown. Actual scope depends on house construction, access, and safety requirements.
What we seal
Air leaks hide where you can’t see them: under the attic insulation, inside chases, and where the walls meet the floor and foundation. We work location by location, starting at the attic floor and following the Department of Energy’s work specifications for air sealing an attic floor.1
ENERGY STAR lists kneewalls, chases, and rim joists among the most common household air leaks. Sealing them makes your insulation perform better and your home more comfortable.2
- In the attic: the hatch, duct boots, plumbing vents and wiring, top plates, recessed lights, bath fans, dropped soffits, flues and chimneys, and kneewalls.
- Large plumbing and HVAC chases, blocked and sealed.
- Rim joists and floor-to-foundation connections, where accessible.
- Exterior wall penetrations for utilities, hose bibs, and wiring.
- Doors and windows: weatherstripping, door sweeps, and caulk at the frame.
Material matched to the gap
Each gap gets the material made for its size and location.2
- Gaps up to 1/4 inch
- Caulk
- Gaps 1/4 to 3 inches
- Expanding foam
- Large openings
- Rigid board or blocking, sealed at the edges, for chases, soffits, and kneewall cavities
- Rim joists
- Caulk or expanding foam, matched to the gap
- Wall penetrations
- Caulk or expanding foam around utility lines, hose bibs, and wiring
- Flues and chimneys
- Fire-safe materials: metal flashing and high-temperature caulk, keeping the required clearance. No changes to the equipment
- Doors
- Weatherstripping and a door sweep
- Windows
- Caulk at the frame
How we do it
Find
We locate the leaks in the attic, along the walls and floor, and around doors and windows.
Big holes first
Chases, soffits, kneewalls, and the attic hatch, where the most air moves.
Small gaps
Top plates, wiring, plumbing, lights, fans, rim joists, and wall penetrations.
Doors and windows
Weatherstripping, door sweeps, and caulk.
Show you
Before-and-after photos of the sealed areas, emailed to you.
Air sealing rates
Every home is different, so we quote air sealing by scope after we look.
| Service | Price |
|---|---|
| Attic air sealing | Typically $600–$1,200Larger or harder-to-reach attics are quoted higher |
| Door weatherstripping and sweep | $150–$250 per door |
| Window caulking | Quoted with the job |
| Chases, rim joists, and exterior wall penetrations | Quoted with the job |
One lump-sum price, with no sales tax added. You get a firm written price before any work starts.
Included at no extra charge
- Sealed to the Department of Energy’s attic air sealing specifications.
- Before-and-after photos of the sealed areas, emailed to you.
Questions about air sealing
Is air sealing the same as insulation?
No. Insulation slows heat moving through your attic floor. Air sealing stops air moving through the gaps in it. They work together, so we seal first and insulate second.
Do you air seal when you insulate?
Yes. Every attic insulation job starts with sealing the attic floor.
Can you seal around my recessed lights?
Lights rated for insulation contact are sealed at the trim and covered. Older lights get a sealed box that keeps the required clearance.
How do you seal around flues and chimneys?
With fire-safe materials, metal flashing and high-temperature caulk, keeping the clearance the building code requires. We do not modify the flue, the chimney, or the equipment they serve.
Do you seal more than the attic?
Yes, where we can reach it. The scope can include large plumbing and HVAC chases, rim joists and floor-to-foundation connections, exterior wall penetrations, and kneewalls. Your written quote lists the locations included.
Can you do just doors and windows?
Yes. Weatherstripping, door sweeps, and caulking can be done on their own or with an attic job.
Other services
Find out where your home leaks air.
Call for a free estimate. We’ll show you the leaks and give you a firm price before any work starts.
Sources
- U.S. Department of Energy and National Renewable Energy Laboratory, Standard Work Specifications job aids: Air Seal Attic Floor.
- ENERGY STAR, A Do-It-Yourself Guide to Sealing and Insulating with ENERGY STAR.
Results vary by home.