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Insulation Cost Calculator

What insulating an attic or walls costs, by type.

Your measurementsEvery assumption editable01

Wall or attic area. Use the insulation calculator for the quantity.

Material and installation together — these are rarely priced apart.

Sealing penetrations and the attic plane. Often the better value than adding depth.

Vacuum-out of contaminated or settled material.

1.00 is the national average. Best set by dividing a real local quote by this calculator's midpoint.

Estimated costCalculated live02

Result

$2244–3740estimated

Midpoint $2992 — about $2.49 per sq ft

Area insulated
1200 sq ft
Materials
$864
Labor39% of the subtotal
$1056
Air sealing
$800
Subtotal
$2720
Contingency10%
$272
Midpoint estimate
$2992
Likely range±25%, the usual concept-stage spread
$2244 – $3740
Cost per sq ft
$2.49

This is a budgeting figure, not a quote. Regional labor rates vary by a factor of two or more across the country, and the same job priced in a busy season and a quiet one can differ by a third. Get three local quotes before committing to anything.

The range matters more than the midpoint. Construction estimating works to roughly ±25% until a scope is drawn and priced, and a single confident number would be pretending to a precision that does not exist at this stage.

Labor is usually the larger half and the more variable half. If the figure looks wrong, the labor rate is almost always the input to revisit first — material prices are far more consistent between regions than crews are.

Insulation is quoted installed rather than as material plus labor, so the rates here carry both. Air sealing is separate — and it is frequently better value than adding depth.

Why use this tool?What it does differently03

Why use this tool?

Four types

Blown fibreglass through closed-cell spray foam, a spread of five to one.

Air sealing separated

Often the better value than more insulation. Sealing leaks beats insulating over them.

Removal costed

Vacuuming out contaminated or settled material, which is real work.

Installed rates

As the trade quotes it, rather than an artificial material-plus-labor split.

How this worksThe method04

How this insulation cost calculator works

Insulation contractors quote installed prices per square foot rather than separating material and labor, so the rates here do the same. The result splits them roughly in half only so the labor share reads sensibly against the site’s other cost calculators.

Air sealing is a separate line because it is a separate job, and frequently the higher-value one. Insulating over unsealed penetrations lets air bypass the insulation entirely, which is why sealing first is standard practice.

Removal applies where existing material is contaminated, settled or has to come out for access. It is straightforward for loose fill and considerably more involved for old batts.

How to use itStep by step05

How to use it

  1. Step 1: Measure the area

    Attic floor or wall area. The insulation calculator handles the quantity.

  2. Step 2: Pick the type

    Blown fibreglass is cheapest per square foot; spray foam is several times that but air-seals as it goes.

  3. Step 3: Budget the air sealing

    Usually the best value in the whole job.

  4. Step 4: Check for existing material

    Removal is only needed if it is contaminated or in the way.

Example usageWorked figures06

Example usage

A 1,200 sq ft attic in batts
At $1.60 per square foot installed plus $800 of air sealing — about $2,992 midpoint, ranging $2,244 to $3,740. That is $2.49 per square foot all in.
Blown fibreglass instead
At $0.90 the same attic is roughly $2,068. Blown material also covers awkward areas batts leave gapped.
Closed-cell spray foam
At $4.50 the same area runs about $7,216 — far more, but it air-seals as it goes, which can make the separate sealing line unnecessary.
Frequently asked questionsCommon questions07

Frequently asked questions

How much does attic insulation cost?

Roughly $1 to $2.50 per square foot installed for blown fibreglass or batts. Spray foam runs $4 to $7, and air sealing is usually a separate line.

Is spray foam worth the extra?

Sometimes. It air-seals as it insulates, which can replace a separate sealing job, and it performs better per inch. Whether that justifies several times the price depends on the assembly and your climate.

Should I air seal before insulating?

Almost always, and it is frequently the better value of the two. Insulating over unsealed penetrations lets air bypass the insulation entirely.

Do I need to remove old insulation?

Only if it is contaminated, wet or in the way. Settled but dry fibreglass can usually be topped up rather than removed.

How long does insulation take to pay back?

Attic insulation is among the fastest efficiency measures, often paying back in a few years. Wall insulation in an existing house is slower because access costs more than the material.

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