Your priorities
How it works
How does this calculator work?
The comparison runs on three inputs — your stated priority (performance, cost, or a middle ground), whether you have a known air-sealing problem, and where the insulation is going. Rim joists, crawl space perimeters, and irregular spaces generally favor spray foam's ability to fill odd geometry and air-seal in one pass. A known air-sealing problem plus a performance priority points toward foam's combined R-value-plus-air-seal property. A cost priority on a standard, accessible attic points toward blown-in.
This tool compares MATERIALS, not rebate eligibility. Xcel's and Efficiency Works' published rebate figures are keyed to the LOCATION insulation is installed (attic, wall, crawl space), not the material — a blown-in attic job and a spray-foam attic job fall under the same location-based figures. See the relevant service page for those.
According to Xcel Energy, “Xcel's insulation and air sealing rebates pay 30% of project cost for gas-heat customers, up to $500 for attic insulation, $350 for wall insulation, and $400 for air sealing, with a 1.5x multiplier for customers whose heating fuel is Xcel gas.”
According to Efficiency Works (Platte River Power Authority program, for Longmont Power & Communications electric customers), “Efficiency Works pays $1.16 per square foot for most insulation measures (conditioned crawl space, basement wall, cantilever floor, exterior wall, cathedral ceiling, conditioned attic) and $0.77 per square foot for flat-ceiling attic insulation, available only to residential electric customers of Longmont Power & Communications.”
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30 seconds to fill out. Free quote, no high-pressure follow-up.
We've Got It. Here's What Happens Next.
We've got your info and are routing it to a local pro. When they call, here's what to look for in the quote you receive: (1) R-value target — the model energy code for Climate Zone 5 calls for R-49 to R-60 attic insulation; ask what your contractor is quoting to. (2) Air sealing scope — insulation alone does nothing if air leaks aren't sealed first, and Xcel requires a blower door test to rebate it. (3) Rebate handling — ask which programs your specific address qualifies for. Xcel and Efficiency Works are separate programs with separate paperwork, and not every address qualifies for both. (The federal IRA Section 25C tax credit ended December 31, 2025 — no federal insulation credit applies to 2026 work. Xcel Energy's insulation and air-sealing rebate remains active for its gas and electric customers. Longmont Power & Communications electric customers may separately qualify for an Efficiency Works rebate — check your bill to see which utility serves your address. Boulder County EnergySmart pays a third, income-qualified-only rebate as of January 1, 2026.) (4) Removal scope — older homes often need old insulation removed before new install. If a quote skips all four, get another quote.
Frequently asked
Frequently asked about spray foam vs blown-in comparator
Does spray foam qualify for a bigger rebate than blown-in?
No — neither Xcel nor Efficiency Works publishes a rebate figure tied to material choice. Both key their dollar figures to WHERE insulation is installed (attic, wall, crawl space), not what it's made of. A spray-foam attic job and a blown-in attic job fall under the same attic figures.
Is spray foam always better than blown-in?
No — it costs more per square foot, and for a standard, accessible attic without a specific air-sealing problem, blown-in is a common, cost-effective choice that performs well. Foam's real advantage is combined air sealing plus R-value in one step, which matters most in tight, irregular spaces or when air leakage is a known problem.
What's the difference between open-cell and closed-cell spray foam?
Closed-cell adds roughly R-6 to R-7 per inch and, at sufficient thickness, acts as a vapor barrier. Open-cell adds roughly R-3.5 to R-3.8 per inch and stays vapor-open. Closed-cell is more common in crawl spaces and rim joists where vapor control matters; open-cell is sometimes used in vented attic assemblies or for sound dampening.
Can I mix approaches — foam in some areas, blown-in in others?
Yes, this is common. A hybrid approach (sometimes called flash-and-batt when foam is paired with batts rather than blown-in) uses foam where its properties matter most — rim joists, a tricky corner — and blown-in for the bulk of a standard attic area.
Does this tool give me a price?
No — this tool compares which approach fits your priorities, not cost. See the Insulation Cost Calculator for a price estimate once you know which approach you're considering.
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