Services
Air sealing
Most of a cold house's heat loss is air going through small holes. We find them with the fan running and close them one at a time.
Air sealing comes before insulation because insulation slows heat but does not stop moving air. The report lists each leak with a photo, and the crew works down that list. When the last one is closed we test again.
What's included
A blower door test before and after
Attic hatch, top plates and chimney chases
Rim joists and sill plates
Wiring, plumbing and duct penetrations
Photos of each seam, before and after
Combustion safety check of furnace or boiler and water heater
Cost
What changes the price
The house's size and shape
More floors and more corners mean more seams to find and close.
How accessible the leaks are
An open attic floor is quick. A finished knee wall or a cramped chase takes longer.
What the framing is
Balloon framing, stone foundations and old additions each hide different gaps.
What the materials are
Some seams take foam, some take tape and membrane, some need a patch of rigid board.
Combustion appliances
A chimney or a gas appliance that needs more air changes the plan.
How it goes
This work, in order
- 01Day one
Step 1: The test and the leak hunt
Fan in the door, smoke pencil and thermal camera in hand. Every leak gets a number and a photo.
- 02The report
Step 2: The ranked list
The big leaks first: hatch, chimney chase, rim joist. The list is in the report.
- 03On site
Step 3: Sealing
The crew works from the attic down, then the basement up, with the fan running so they can feel the difference.
- 04Last day
Step 4: The second test
We run the same test the same way. You get both numbers beside each other.
Not included
What this work leaves out
Insulation
It follows air sealing and has its own page and its own line in the estimate.
A promise of a number
We tell you what the test measured. We don't promise how low the second number will be.
New ventilation equipment
If the report calls for it, it is a separate line; see the heat pumps and ventilation page.
Before the work
Permits and rules
In an existing home, air sealing alone rarely needs a permit. A new vent, a changed chimney or any new wiring or gas work can. We ask your town's building official when the report says one is involved, and tell you the answer.
Houses built before 1978 may have lead paint on trim, sills and doors. Work that disturbs painted surfaces follows EPA's lead paint rule. See the certificate and insurance page.
Questions about this work
Will my house be too tight?
A house can be too tight for its ventilation. We measure first, check your combustion appliances before and after, and the report says what fresh air the house needs.
Can I do some of this myself?
Some of it, yes: weatherstripping a door, foaming a small gap. The report marks which lines a handy owner can do and which need a crew.
Do you air seal and insulate in the same visit?
Often. We seal first, then insulate, and we test between if you ask.
How long does it take?
A small attic and basement can be a few days. A large old house takes longer. The estimate gives a window.
Start with the test
Book a blower door test and we'll find the leaks first.