Spray Foam Insulation cost: Janesville vs Madison (2026)
In 2026, spray foam insulation is about 3% less expensive in Janesville than in Madison. Most homeowners pay around $3,800 in Janesville versus $3,900 in Madison — a gap of roughly $100.
Janesville WI
Lower costTypically around $3,800
Madison WI
Typically around $3,900
Janesville vs Madison: full breakdown
| Factor | Janesville | Madison |
|---|---|---|
| Typical 2026 cost | $3,800 | $3,900 |
| Estimated range | $1,500–$6,100 | $1,550–$6,200 |
| Labor index (vs US) | ×0.96 | ×0.98 |
| Climate zone | Cold | Cold |
| Climate factor | ×1.06 | ×1.06 |
| Local permit | None | None |
| Labor share | $2,100 | $2,150 |
| Materials/equipment | $1,700 | $1,750 |
All figures are 2026 localized planning estimates for spray foam insulation — get an actual quote before you commit.
Is the gap worth worrying about?
That 3% gap is small — for spray foam insulation it's usually less than the spread between two local contractors' quotes, so the metro matters far less than who you hire and when you buy.
Spray foam insulation by type: Janesville vs Madison
We localize each spray foam insulation type separately for both metros, applying the same labor, climate and permit adjustments each time, so you're comparing like for like.
| Type | Janesville | Madison |
|---|---|---|
| Open-cell | $1,500–$4,550 | $1,550–$4,650 |
| Closed-cell | $2,550–$7,100 | $2,600–$7,250 |
These are 2026 planning figures for spray foam insulation, localized to each city — not formal quotes.
Spray foam insulation by area: Janesville vs Madison
Spray foam is priced by board foot (1 sq ft at 1 inch thick), which works out to about $1.50–$5 per sq ft of surface installed depending on foam type and thickness. Closed-cell costs more but adds twice the R-value per inch.
| Size | Janesville | Madison |
|---|---|---|
| 500 sq ft | $900–$2,450 | $950–$2,500 |
| 1,000 sq ft | $1,500–$4,050 | $1,550–$4,150 |
| 1,500 sq ft | $2,250–$5,550 | $2,300–$5,700 |
| 2,000+ sq ft | $2,850–$6,600 | $2,900–$6,750 |
Localized 2026 planning estimates — not quotes. Each city adjusts the national spray foam insulation range for local labor, climate and permits.
Cheapest time for spray foam insulation in either city
Demand for insulation spikes every fall as winter approaches, pushing prices with it. Spring and summer avoid that crowd, and utility rebate pools are frequently still fresh that early in the year.
How much insulation is worth paying for?
Where an insulation budget lands depends less on square footage than on three calls — the R-value you target, whether air-sealing rides along, and which material fills the cavity.
The air-sealing case
Skip air-sealing and you're insulating around the very holes letting conditioned air leak out. Caulk, foam and weatherstripping are inexpensive and often return more felt comfort than a thicker blanket of insulation ever would — insist the crew handles the leaks before they bury them.
The rebate case
Few home projects come with rebate support like insulation does — utility and state programs routinely offset a meaningful slice of the bill (the federal 25C credit closed in December 2025). Run your address through DSIRE first, and book when a program's yearly budget has just refilled.
The R-value case
Aim for the R-value the DOE assigns your zone, not a round number that sounds close enough. Every point you fall short is comfort you don't feel and utility savings you never bank — savings that would have covered the extra material several times over.
Payback is the whole point with insulation, and it arrives fastest when the job is done in full: air-sealing, the DOE-recommended R-value for your climate zone, and whatever utility rebates you qualify for. Trimming any one of those trims the return, not the cost.
Janesville vs Madison
Is spray foam insulation cheaper in Janesville or Madison?
Janesville comes out ahead here, at roughly $3,800 for spray foam insulation compared with $3,900 in Madison — a 3% ($100) gap as of 2026.
Why does spray foam insulation cost more in Madison than Janesville?
It comes down to labor: Madison indexes at 0.98 against Janesville's 0.96. The cold-vs-cold climate difference adds to the gap.
How much is spray foam insulation in Janesville, WI?
In Janesville, spray foam insulation typically runs $1,500–$6,100 in 2026, with most homeowners paying around $3,800.
When is the cheapest time to buy spray foam insulation — and does it differ by city?
It doesn't vary by location — Spring and summer is the discount window in both Janesville and Madison (roughly 5–10% off), while the pre-winter fall rush tends to be the most expensive in either city.
Should I choose where to live based on spray foam insulation cost?
Probably not. Yes, $100 is a real gap, but it's a one-time cost you can partly offset in Madison with off-season timing and tighter bids. Long-term factors like energy prices and home condition matter more than this one number.
Compare spray foam insulation in other cities
Updated June 2026 · By Serhat Özçelik