A homeowner checklist for comparing attic insulation estimates

Two estimates arrive. One is noticeably cheaper. Nothing in either document makes it obvious why.

This checklist is the tool for that moment. Work down it with both proposals in front of you and the difference usually explains itself. It is written to be used with any contractor's estimate — including ones that have nothing to do with this website.

Existing condition

• Does the estimate say what insulation is in the attic now, and how deep?
• Does it say whether that material is staying or being removed?
• If it is staying, does the R-value calculation account for it?
• Was anyone actually in the attic before the number was written?

An estimate produced without an attic inspection is a price for a square footage, not a scope for a project.

Air sealing

• Is air sealing included at all?
• Which locations: hatch, top plates, plumbing and wiring penetrations, chases, recessed fixtures, exhaust fan housings, flue and chimney surrounds?
• What materials at each — and fire-rated material where required?
• Is it priced separately, so it can be compared?

The most common single difference between a cheap quote and a complete one ^{[1] [2]}.

Product and R-value

• Is the product named, not just "blown insulation"?
• Is the installed R-value stated, not only the depth?
• Is the resulting total R-value stated, including existing material?
• Does the target match the guidance for a Zone 4A attic — R-60 for an uninsulated attic, R-49 where three to four inches already exist ^[3]?
• If it is lower than that, is there a stated reason, such as depth available at the eaves?

Consumer guidance is to establish the R-value being installed rather than rely on thickness ^[4], and federal rules govern how R-value is disclosed in these sales ^[5].

Coverage and verification

• What coverage area is quoted, in square feet?
• What settled depth corresponds to the stated R-value for that product?
• How many bags or packages, and will that be shown on the invoice?
• Will depth markers be installed so coverage can be checked?

Bag count against coverage area is the arithmetic that confirms you received what was quoted. It is a fair thing to ask for and easy for a competent contractor to provide.

Removal

• If removal is proposed, what specifically justifies it?
• Is it all of the material, or affected areas only?
• Is disposal included and priced?
• Is containment and route protection described?
• Is air sealing included once the deck is clear?

Age alone is not a justification. See the removal decision guide.

Ventilation and eaves

• Are baffles included at the eaves, and at how many rafter bays?
• Is existing soffit-vent blockage being corrected?
• If the attic is unvented or is being converted, is that explained?

Attic hatch

• Is the hatch or pull-down stair being insulated?
• Is it being weatherstripped?
• Is a dam or box included so loose-fill does not spill through?

Frequently omitted, and it is one of the larger openings in the ceiling.

Lights, flues and heat sources

• Are recessed fixtures being confirmed as rated for insulation contact, boxed out, or replaced?
• Is the required clearance around flues and chimneys being maintained?
• Is any of this shown as a separate line, or assumed?

Ducts and exhaust

• Are bath and kitchen exhaust ducts confirmed to terminate outdoors rather than into the attic ^[6]?
• If not, who is correcting that, and is it in this quote or another trade's?
• Is attic ductwork condition noted?

Moisture, pests and suspected hazardous material

• Does the estimate note any moisture staining, and is a source identified?
• If pest contamination is present, what is the plan, and who closes the entry points?
• If anything resembling vermiculite was seen, is the estimate conditional on it being evaluated first ^[7]?

A contractor who proposes insulating straight over an unexplained wet patch is telling you something useful about how they work.

Protection and clean-up

• How is the living space protected during the work?
• What does clean-up cover, and is debris removal included?
• How many days, and does anyone need to be home?

Paperwork

• Written scope, not a single-line total
• Licensing and insurance details, verified with the issuing body rather than taken from a logo on a truck
• Manufacturer warranty on the product, and what the contractor warrants on the workmanship — including what voids either
• Payment schedule and what triggers each stage
• Explicit exclusions

That last item is where a low bid usually reveals itself. Read the exclusions on both proposals before comparing the totals.

Two questions worth asking out loud

"What did you see in the attic that surprised you?" A contractor who was genuinely up there has an answer.

"What is in your quote that a cheaper one would leave out?" Most will tell you plainly, and the answer is usually air sealing, baffles or fixture detailing.

Use these details to request an estimate

The more of this you can answer before the visit, the more useful the visit is. Share the address and what is prompting the project.

Related: attic insulation · air sealing · removal · R-value guide