Air sealing: what's yours, what's theirs.
The highest-return work in home energy splits cleanly: DIY the accessible leaks this weekend, hire the attic plane. Here's the honest line between the two.
The highest-return work in the whole retrofit
Air leaks can carry 10–20x more heat through an insulated assembly than conduction alone — which is why sealing comes before insulating in the retrofit sequence, always. It's mostly labor and foam, so it's cheap relative to what it saves, and it makes every dollar of insulation after it perform as rated.
If you haven't found your leaks yet, start with the DIY energy audit checklist — it's the find-the-leaks half of this job.
Genuinely yours: patience, not trade skills
Weatherstrip doors and windows
Rope caulk, V-strip, and door sweeps. An afternoon of patient work, and the materials are cheap at any hardware store.
Outlet and switch gaskets
Foam gaskets behind the cover plates on exterior walls. Ten minutes each, no skill required beyond a screwdriver.
Caulk visible gaps
Where trim meets wall, where pipes enter under sinks, around window frames. Paintable acrylic-latex caulk, cut the tip small.
Rim joist foam board
In an open, dry basement: cut rigid foam to fit each bay, seal edges with canned foam. Tedious but genuinely effective.
Where the pro earns the fee
The attic floor plane
Top plates, wire and pipe chases, bypasses buried under insulation, dropped soffits. This is where the big leaks live, and finding them means moving insulation and knowing where to look.
Anything needing a blower door
Pros seal with the blower door running — it shows them exactly what's still leaking and proves the improvement when they're done. That test-out number is also what rebate programs pay on.
Recessed lights and chimneys
Fire-rated covers and clearances are safety items, not judgment calls. Same for anything near flues and combustion appliances.
Dense-pack as air sealing
Dense-packed cellulose in walls seals as it insulates — one of the reasons it's the retrofit material of choice. That's contractor equipment, not a rental.
If you want the rebate, you usually want the pro
Most efficiency programs pay for air sealing as professional work verified by a blower door test — the test-out number is the receipt. DIY work saves you money on your bills but generally can't claim the rebate. Since programs in strong states cover a large share of professional air sealing (and typical whole-home projects run about $1,000–$4,000 at market rates), the subsidized pro job is often the better deal even for capable DIYers. Check your state's programs before you decide which list to work.
A simple decision framework
Renting, or tight budget? Work the DIY list now. It costs little and travels with your utility bill.
Planning insulation or a heat pump? Go professional, bundled with the insulation work and sized by an assessment — that's the sequence paying for itself. Get quotes that include test-out numbers.
Somewhere in between? DIY the doors and outlets this month; put the attic plane on next year's plan with the insulation budget.
Air sealing questions
Is DIY air sealing worth it?
Yes — the accessible stuff (doors, windows, outlets, visible gaps) is cheap, low-skill, and pays back fast. Just don't mistake it for the whole job: the biggest leaks are usually in the attic floor and rim joists, where professional work with a blower door earns its fee.
Can you over-seal a house?
A house can get tight enough to need mechanical ventilation — that's a solvable, well-understood situation (an ERV or HRV), not a reason to leave leaks. Professionals check ventilation rates as part of the work. 'Houses need to breathe' is a myth; people need fresh air, and controlled ventilation beats random leaks at providing it.
How much does professional air sealing cost?
Published national pricing puts typical whole-home professional air sealing at roughly $1,000–$4,000 depending on size and scope, with comprehensive attic-plus-basement projects running $2,000–$5,000 or more. In strong-program states, rebates routinely cover a large share of it.
Does air sealing qualify for rebates?
In most state and utility efficiency programs, yes — usually as professional work with a blower door test, often bundled with insulation. DIY work generally doesn't qualify because there's no test-out number to pay on. Check your state page for the specific programs.
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Your state probably pays for the professional half.
Air sealing is among the most heavily subsidized work in home energy. See what you qualify for before deciding what to DIY.
Match my rebates