Spray foam insulation in Denver, CO: get up to 3 quotes from vetted local installers
Request free quotes from up to three vetted spray foam installers serving Denver and nearby Denver County. Below: what your climate zone means for open vs closed cell, how much insulation to ask for, Colorado's energy code, and the rebates we could verify.
- Climate zone: 5B (2021 IECC)
- Attic target: R-60 (ENERGY STAR, uninsulated attic)
- State code: Home-rule state with a state minimum energy code
- Utility rebates we verified: Xcel Energy Colorado: Insulation & Air Sealing
- Federal 25C credit: ended for 2026 installs
Facts last checked October 16, 2026. Sources are linked in each section.
Where we match quotes from this page
Requests from Denver and ZIP codes whose center is within about 20 miles of it go to our Denver, CO partner installers (89 ZIP codes): 80002, 80003, 80004, 80005, 80007, 80010, 80011, 80012, 80013, 80014, 80015, 80016, 80017, 80018, 80019, 80020, 80021, 80022, 80023, 80024, 80027, 80030, 80031, 80033, 80045, 80110, 80111, 80112, 80113, 80120, 80121, 80122, 80123, 80124, 80126, 80128, 80129, 80130, 80137, 80202, 80203, 80204, 80205, 80206, 80207, 80209, 80210, 80211, 80212, 80214, 80215, 80216, 80218, 80219, 80220, 80221, 80222, 80223, 80224, 80226, 80227, 80228, 80229, 80230, 80231, 80232, 80233, 80234, 80235, 80236, 80237, 80238, 80239, 80241, 80246, 80247, 80249, 80260, 80264, 80266, 80290, 80293, 80294, 80401, 80419, 80601, 80602, 80603, 80640. Outside these? Send the form anyway and we'll tell you if we can't match you.
Climate zone 5B: what it means for spray foam
Denver's central point is in Denver County, which the 2021 IECC county map assigns to climate zone 5B (cold in DOE's Building America terms). Zone 5B is a dry ("B") zone, which drives the vapor and R-value rules below.
Other counties within our Denver service radius: Adams County (5B), Arapahoe County (5B), Boulder County (5B), Broomfield County (5B), Douglas County (5B), Jefferson County (5B), Weld County (5B). All are zone 5B too.
Source: PNNL-33270, Guide to Determining Climate Zone by County (IECC 2021).
Open cell vs closed cell in Denver, CO
Attic roofline: in zone 5B, IRC Section R806.5 requires that air-impermeable insulation under an unvented roof deck either be a Class II vapor retarder itself or be covered with a vapor-retarder coating. Closed-cell foam meets that on its own at typical thicknesses; open-cell foam needs vapor-retarder paint. In a hybrid assembly the foam layer at the deck must be at least R-20.
Rim joists and basement walls are where spray foam pays off fastest in cold climates: closed cell air-seals the leaky band joist and blocks moisture in one pass, which is hard to do with batts.
How much insulation to ask for
| Where | ENERGY STAR recommendation for zone 5B |
|---|---|
| Attic, uninsulated | R-60 |
| Attic with 3–4" of existing insulation | add R-49 |
| Floor over unconditioned crawlspace/basement | R-30 |
| Basement or crawlspace walls | R-15 continuous or R-19 cavity |
| Exterior walls (when re-siding) | add R-5 to R-10 insulative wall sheathing beneath new siding |
To reach R-60 with foam alone you'd need roughly 16.2–17.1" of open cell (about R-3.5 to R-3.7 per inch) or 8.6–12.0" of closed cell (about R-5 to R-7 per inch). Many roofline spray foam jobs are installed thinner than that and justified through the code's performance path or the unvented-attic rules, so ask every installer to write the foam type, thickness and resulting R-value on the quote and explain how it meets your local code.
Source: ENERGY STAR, Recommended Home Insulation R-Values (based on 2021 IECC). ENERGY STAR's figures are recommendations for existing homes; your local code sets the legal minimum for new work.
Colorado energy code
Home-rule state with a state minimum energy code. Under 2022 state law, Colorado jurisdictions must adopt the state minimum energy code whenever they adopt or update any other building code, so Denver, Colorado Springs, Fort Collins and Greeley may each be on a different edition. Confirm with your building department.
Source: NAHB, "Residential Provisions of the IECC: State Adoption Status" (current as of May 2026); official state status at DOE Building Energy Codes Program.
Homes in Denver, CO
Census figures for Denver city (ACS 2020–2024 5-year estimates): about 359,581 housing units, a median year built of 1975, 56% built before 1980 and 20% built in 2010 or later. 41% are single-family detached homes and 0% are mobile/manufactured homes. 49% of occupied homes are owner-occupied, with a median owner-reported home value of $616,000.
- With 56% of homes built before 1980, many attics here predate modern energy codes. Older attics often need old insulation removed or air-sealed first, and knob-and-tube wiring must be checked before any insulation covers it. Ask whether removal and prep are in the price.
- 61% of homes heat with utility gas. Spray foam makes a house much tighter, which changes how gas furnaces, water heaters and fireplaces draft, so ask whether the installer (or your HVAC contractor) will do combustion safety testing after the job. Some utility rebates require it.
Rebates and incentives for Denver, CO
Utility programs that may apply, depending on which utility serves your address:
Xcel Energy Colorado: Insulation & Air Sealing
Rebates through participating contractors; published 2026 summaries list 30% of cost up to $500 for attic and $350 for wall insulation and $400 for air sealing, with 1.5× amounts for Xcel gas-heated homes. Confirm amounts on Xcel's page.
Read on the program's own page October 16, 2026. Programs change; confirm before you sign.
Colorado state Home Energy Rebates
Limited, paused, or fully reserved Colorado Home Energy Rebate Program
Electrification/appliance rebates (HEAR): "The HEAR single-family program is now closed for both Region 1 (the Front Range) and Region 2 (All Other Counties). Rebates for small multifamily buildings will be available in 2026."
Whole-home efficiency rebates (HOMES/HER): "Home Efficiency Rebates (HER) will support whole-home energy efficiency improvements. These rebates will be available to manufactured/mobile homes and large multifamily buildings in 2026."
Max rebate (per official page): $14,000
Official source: Colorado Energy Office (CEO) (page says: Updated August 2026). Status text compiled via referencesource.org, last checked by them August 25, 2026. Full Colorado rebate page →
What spray foam costs (national published ranges)
We don't have enough local quotes for Denver, CO to publish local prices, and we won't make them up. These national ranges are a starting point; your installers' quotes are what count.
| Example job (typical thickness) | Estimated installed range |
|---|---|
| 1,000 sq ft attic roofline, open cell (6") | $3,600–$9,600 |
| 1,000 sq ft attic roofline, closed cell (3") | $3,900–$9,300 |
| 1,500 sq ft walls, open cell (3.5") | $3,150–$8,400 |
| 1,500 sq ft walls, closed cell (2") | $3,900–$9,300 |
| 200 sq ft rim joists, closed cell (2") | $520–$1,240 |
Board feet × Angi's 2026 installed price per board foot. Angi reports a national average spray foam project of $2,888 (typical $1,455–$4,337). Check a quote you already have →
Questions to ask each installer
- Foam type, brand, thickness and resulting R-value for each area, in writing.
- Which climate zone and code edition they're designing to.
- Whether removal of old insulation, air sealing, and any required ignition/thermal barrier coating are included.
- Whether they participate in Xcel Energy Colorado: Insulation & Air Sealing, and who files the paperwork.
- Whether they'll do (or coordinate) combustion safety testing if you have gas appliances.
FAQ
What climate zone is Denver, CO in?
Denver County is IECC 2021 climate zone 5B, per PNNL's county list (PNNL-33270).
Should I use open-cell or closed-cell spray foam in Denver, CO?
In zone 5B, open cell under a roof deck needs a vapor-retarder coating (IRC R806.5); closed cell doesn't. Closed cell is also the standard choice for rim joists and basement walls.
How much attic insulation do homes in Denver, CO need?
ENERGY STAR recommends R-60 for an uninsulated attic in zone 5B (or adding R-49 on top of 3–4 inches of existing insulation). Colorado's code: Home-rule state with a state minimum energy code.
Are there spray foam or insulation rebates in Denver, CO in 2026?
The federal 25C tax credit does not apply to insulation installed after December 31, 2025. Utility programs that may apply, depending on which utility serves your address: Xcel Energy Colorado: Insulation & Air Sealing. Colorado's state Home Energy Rebate program status: Limited, paused, or fully reserved.
How much does spray foam cost in Denver, CO?
We don't publish local prices until we have enough real local quotes. National published ranges are about $0.60–$1.60 per board foot for open cell and $1.30–$3.10 for closed cell, installed (Angi, 2026), and many companies have a $1,000–$2,000 minimum.
How does requesting quotes work?
Fill in the form once. We pass your request to up to three vetted partner installers who serve Denver, CO, and they contact you to schedule an estimate. It's free and there's no obligation.
Other areas we serve in Colorado
Greeley · Fort Collins · Colorado Springs · All Colorado service areas · All service areas