Two insulation estimates can list similar totals while describing different parts of a house. Before comparing the price, identify exactly what each bidder measured and what that quantity includes.
Ask For A Boundary Around Every Quantity
A square-foot figure needs a location and a measurement basis. Ask the bidder to name the surface or cavity, identify its boundaries on a sketch or photographs, and say whether openings or inaccessible sections were deducted. Have the provider distinguish measured quantities from allowances that still need verification.
DOE explains that insulation types are selected for their location and required performance, and that R-value describes resistance to heat transfer. Area, thickness and R-value describe different things. A larger area number by itself does not show that a proposal will insulate more effectively.
Use The Same Questions For Each Bid
Let the bidder supply and verify the measurements. This comparison sheet does not require you to enter an attic or open a wall.
| Field | What To Record |
|---|---|
| Area identifier | Name the attic floor, roof slope, wall section or other proposed location. Match it to a sketch. |
| Measured area | Record quantity, units, who measured it and any deduction for openings. Flag estimates. |
| Existing material documented | Ask what was identified, where it was observed and what could not be inspected. |
| Proposed product | Record the product or specification, intended location and proposed installed R-value. |
| Quantity basis | Ask how area, depth, coverage or other quantities produce the quoted material amount. |
| Access exclusion | List sections the bidder cannot reach and work needed to make them accessible. |
| Verification needed | Record unresolved conditions, who checks them and when the price or scope becomes final. |
Compare Like Areas Before Comparing Totals
Illustrative example: one estimate describes the attic floor; another includes wall cavities beside a finished room. Their square-foot totals do not cover the same surfaces. Request a revised breakdown separating each location, then compare the common portion and the additional work.
For an existing house, ask how the bidder distinguished material already present from material being added. Have the proposal identify any removal, disposal or preparation separately. Ask what record you will receive after installation to show where the work was completed and how its specified coverage was checked.
Resolve Conditions That Could Change The Bid
ENERGY STAR identifies difficult access, damp insulation, moisture damage and ventilation issues as reasons for professional attention before proceeding with attic air sealing. Ask the bidder how relevant conditions will be evaluated and who handles any prerequisite work. An insulation quantity is not a moisture assessment.
Ask whether air sealing, ventilation evaluation, access work and cleanup are included, excluded or separately priced. Do not infer a bill reduction from a proposed R-value alone. If a bidder predicts savings, request the assumptions, assessment method and limitations for your house before relying on the estimate.
Questions Homeowners Ask
Can I compare bids using price per square foot?
Only after the locations, measurement basis, product, preparation and exclusions are comparable. A unit price can hide a different scope.
Should I measure an inaccessible area myself?
Ask the contractor to identify how it will be measured or treated as an allowance. Do not enter unsafe spaces or disturb existing material to complete this worksheet.
Sources And Local Resources
Sources checked November 9, 2026. Confirm current requirements with the authority responsible for your property.
- DOE Building Science Education: Types Of InsulationR-value and insulation selection by location/application; materials have different uses.
- ENERGY STAR: Attic Air Sealing ProjectProfessional attention for access, damp material, moisture and ventilation conditions; no DIY procedure or incentive claim reused.