What it costs to fully weatherize a house
Most cost guides price one measure at a time. This one assembles the whole envelope: assessment, air sealing, attic, walls, basement. Every line is a published national range, and the total is honest about being a sum.
Five lines, summed honestly
No reliable national whole-house weatherization statistic exists. What exists is solid per-measure pricing, so we sum it and say so.
| Component | Installed range | Applies to | Notes |
|---|---|---|---|
| Energy assessment | $200–$700 | Every house | ~$437 national average. Often free in program states, and programs usually require it first. |
| Air sealing | $1,000–$4,000 | Every house | Standard homes average $1,000–$1,500. Comprehensive attic + basement + crawl scope runs $2,000–$5,000+. |
| Attic insulation | $900–$3,600 | Nearly every house | Blown-in cellulose $0.60–$2.30/sq ft of attic floor. The biggest single savings line. |
| Wall insulation (dense-pack) | $1,600–$4,200 | Optional, by house | Per 1,000 sq ft of wall area, at $1.60–$4.20/sq ft. Worth it in pre-1980 homes with empty wall cavities. |
| Basement / crawlspace | $1,100–$5,900 | Optional, by house | Rim joist only $1,100–$2,300; rim + crawl walls $1,750–$3,800; full crawl treatment $3,600–$5,900. |
Attic pricing is per square foot of attic floor. Dense-pack pricing is per square foot of wall area, which is a different, larger number. Air sealing is not priced by area at all. A "$2 per square foot" quote means nothing until you know which square feet, so compare quotes line by line, never by a blended rate. The retrofit sequencing guide covers what order these lines happen in.
What each component costs, and why
Energy assessment
$200–$700About $437 on average nationally, and always the first line because most programs require one before they pay for anything else. In program states the market rate rarely applies: Mass Save runs no-cost assessments and Energize CT charges roughly a $50–$100 co-pay. The blower door and infrared scan are what turn "the house feels drafty" into a priced work order.
Air sealing
$1,000–$4,000Professional whole-home air sealing spans $1,000–$4,000 depending on size and leak density; standard homes average $1,000–$1,500, and a comprehensive attic + basement + crawlspace scope runs $2,000–$5,000 or more. Contractors often bundle it into insulation quotes, so demand the line item: it is the cheapest work on this page and usually the best savings per dollar. Our DIY vs contractor breakdown covers which parts you can do yourself.
Attic insulation
$900–$3,600Blown-in cellulose runs $0.60–$2.30 per square foot of attic floor installed; blown-in fiberglass $0.50–$2.00. Typical project totals land between $900 and $3,600. Removal of old insulation, deep R-60 targets, and tight access push toward the high end. This is the biggest guaranteed line on most jobs, and it gets its own deep dive in the attic insulation cost guide.
Wall insulation, the big optional line
$1,600–$4,200Dense-pack cellulose in existing walls costs $1.60–$4.20 per square foot of wall area, or $1,600–$4,200 per 1,000 square feet of wall. Brick and stucco exteriors cost more because crews drill from inside and patch drywall. Skip it if your walls already hold insulation; prioritize it if the house predates roughly 1980 and the cavities are empty. If you only fund two lines, attic plus air sealing beats walls alone almost every time. The insulation cost calculator prices your actual square footage.
Basement and crawlspace
$1,100–$5,900The rim joist, the wood band where the house meets the foundation, is the priority: $1,100–$2,300 as a standalone scope, or $2,100–$2,800 for professional spray foam. Rim joist plus crawlspace walls runs $1,750–$3,800, and treating all crawlspace surfaces $3,600–$5,900. Closed-cell foam and tight access drive the high end. For finished-basement wall insulation, get an itemized local quote; published national pricing for that specific scope is not reliable enough to print.
Sticker price is not what program-state homeowners pay
Weatherization is the most subsidized measure class in home energy. State and utility efficiency programs treat envelope work as the cheapest heat they can buy, and many cover 40–100% of it. Where the federal HEAR program has launched, income-eligible households can get up to $1,600 toward insulation, air sealing, and ventilation on top; launch status varies widely by state and several programs are income-restricted, so verify yours rather than assuming the money is claimable today.
One regional honesty note: cold-climate Northeast metros run 20–50% above the national midpoints on this page, and their programs tend to cover more of the bill, so both sides of the math shift together. The Rebate Matcher gives you the state-specific answer in two minutes, and when you are ready for pricing, get weatherization quotes from contractors who work these programs daily.
And if a heat pump is on your list, do this work first: a tighter envelope means smaller, cheaper equipment. The weatherize-before-heat-pump guide shows how much the order matters.
Weatherization cost questions
How much does it cost to weatherize a 1,500 sq ft house?
Summing the national component bands: an energy assessment at $200–$700, standard whole-home air sealing at $1,000–$1,500, and a blown-in attic insulation project at $900–$3,600 comes to roughly $2,100–$5,800 for the core scope, before rebates. That is a derived total, not a surveyed whole-house statistic. Dense-pack walls or basement work add to it, and in strong-program states rebates can cover a large share of the whole number.
What does full weatherization include?
Three things happen on almost every job: an energy assessment, air sealing, and attic insulation. Two more depend on the house: dense-pack wall insulation (mostly pre-1980 homes with empty cavities) and basement or crawlspace treatment (rim joist at minimum). Good crews also handle the supporting items, like bath-fan venting, ventilation baffles, and combustion safety checks.
Is weatherization free for low-income households?
Often, yes. The federal Weatherization Assistance Program delivers no-cost weatherization to income-qualified households through state and local agencies, and many state efficiency programs layer their own income-qualified offers on top. Eligibility rules and waitlists vary by state, so check your state page for who runs the program near you.
Do I need to weatherize before installing a heat pump?
It is the right order. Air sealing and insulation shrink your home's heating load, which means a smaller, cheaper heat pump that runs longer, gentler cycles. Some state programs require an assessment, and sometimes weatherization itself, before they pay equipment rebates. Our weatherize-before-heat-pump guide walks through the sequencing.
What is the cheapest weatherization step?
The assessment, in program states where it is free or close to it: Mass Save offers no-cost assessments and Energize CT runs about a $50–$100 co-pay. Among the actual work, air sealing is the cheapest line at a $1,000–$1,500 average for a standard home, and it typically saves more per dollar than any insulation measure.
Get alerts when weatherization rebates change in your state
Free weekly digest. Unsubscribe anytime. Privacy policy.
Weatherization is the most subsidized work on this site.
In strong-program states the rebate is the biggest line on the whole job. See your state's share before you price anything.
Match my rebatesOr start with a number: the insulation cost calculator prices your attic and walls.