How to vet a contractor for natural insulation in 2027

What to take away

• A contractor who quotes insulation without inspecting the attic and crawl space is quoting a guess.
• Ask what diagnostics they run. Blower door and combustion safety testing separate the trades quickly.
• Air sealing should be a priced line item, not a phrase in a paragraph.
• Get the target depth or density in writing, with verification photographs promised before anything is covered.

The first visit tells you most

A competent contractor goes into the attic and the crawl space, looks at the mechanical equipment, and asks about comfort complaints room by room. One who measures the floor area from the driveway and emails a price is selling material, not performance.

Three questions at the first visit are diagnostic in themselves. What is the existing insulation and is it dry? Where is the air barrier? What combustion appliances are here and how are they vented? A contractor who cannot answer all three after a site visit has not done one properly.

Diagnostics and certification

Ask which tests they perform and whether results are provided in writing. A blower door test before and after quantifies what the work achieved. Thermal imaging in cold weather finds missed areas. Combustion safety testing confirms that appliances still vent correctly once the house is tighter.

Ask about certification for adjacent hazards too. If the house predates 1978 and painted surfaces will be disturbed, the firm needs the relevant federal certification for renovation in older housing. If vermiculite is suspected, the correct answer is to stop and bring in a professional, not to vacuum it out.

Where you want independent context on state programs and contacts, EPA maintains a directory of regional office and state indoor air quality information, which is a reasonable route to whichever state office handles these programs where you live. EPA's radon resources page serves the same purpose for radon measurement and mitigation, including how to reach state radon contacts.

What the quote must contain

Line	Acceptable	Not acceptable
Air sealing	Scope described, priced separately	Mentioned in passing
Insulation material	Product, form, target depth or density	"Natural insulation"
Coverage area	Square footage by area	One lump figure
Ventilation work	Fans, ducting, controls specified	Assumed to exist
Combustion safety	Test named, before and after	Not mentioned
Verification	Photographs and measurements promised	Silence
Exclusions	Written list	Silence

If air sealing is not a separate priced line, you cannot tell whether it is being done. That single row filters a surprising number of bids, and it also makes two quotes comparable for the first time.

Ask for customer references that mean something

Ask for two references from jobs at least two winters old, in houses similar to yours. Recent references show that the crew turned up. Older references show whether the work held.

Ask those homeowners three things: did the drafts stop, did any condensation appear afterward, and did the contractor come back when asked. Then compare the answers against the stage list in our guide to what happens at each stage of the work and the schedule assumptions in the realistic project timeline.

Common questions

Is a blower door test worth paying for? On anything beyond a simple attic top-up, yes. It converts comfort complaints into a measured number.

Should I use a specialist or a general contractor? A specialist, for the diagnostics. General contractors rarely own the testing equipment.

What if the contractor says air sealing is unnecessary? Get a different quote. Air leakage carries more heat and moisture than conduction through the material does.

How do I check work I cannot see? Insist on dated photographs of each area before it is covered, plus depth measurements at several points.