The calculator
Run the attic insulation cost calculator
Enter your attic square footage, current insulation level, and target R-value. The calculator estimates pre-rebate project cost and rebate-adjusted out-of-pocket using Denver-metro 2026 contractor pricing and the alive Xcel rebate stack.
Your project
Most Denver homes 1,200-2,500 sq ft. Conditioned-area square footage is fine if you don't know exact attic.
According to the International Energy Conservation Code, “the 2021 IECC (R402.1.2) sets attic insulation minimums at R-49 to R-60 for Climate Zone 5B, which covers the Denver metro area.”
How this works
How does the attic insulation cost calculator work?
The math: base install runs $1.50–$3.00 per square foot in 2026 Denver pricing. Targeting R-60 (the retrofit recommendation) adds about 15% over the R-49 minimum. Removal of existing material adds $1.50–$3.50 per square foot. Air sealing adds $300–$1,200 fixed.
Rebate math: the Xcel Insulation and Air Sealing Rebate plus the Whole Home Efficiency Bonus typically reduce net cost 20-35% on a qualifying project. Calibrated against the Xcel program documentation and Denver-metro contractor pricing as of May 2026.
According to the Xcel Energy, “qualifying insulation and air-sealing rebates are paid as an upfront discount on the invoice when homeowners work with a participating Xcel Trades Ally contractor.”
Get a quote
Get a Quote Based on Your Numbers
30 seconds to fill out. We'll send your inputs along with the quote request so the contractor knows what you've already calculated.
We've Got It. Here's What Happens Next.
We've got your info. A local pro is reviewing it now. Expect a call within a few hours, or by tomorrow at the latest. While you wait, here's what to look for in the quote you receive: (1) R-value target — current Colorado code is R-49 to R-60 for attics, anything less is under-spec. (2) Air sealing scope — insulation alone does nothing if air leaks aren't sealed first. (3) Rebate handling — Xcel rebate paperwork should be handled for you, not by you. (The federal IRA Section 25C credit expired in 2025 and Colorado HEAR closed for the Front Range — Xcel programs are now the active rebate stack.) (4) Removal scope — pre-1990 homes often need old insulation removed before new install. If a quote skips all four, get another quote.
Related guides
Related services and calculators
According to the Department of Energy, “adequate insulation and air sealing can reduce heating and cooling costs by 10% to 20% in typical homes.”
Frequently asked
What do Denver homeowners ask about this calculator?
Should I use this calculator if my home was built after 2010?
Possibly — but interpret the output cautiously. Post-2010 Denver homes were built to recent code, so most calculator scenarios assume pre-1990 baselines and may overstate the project value for newer homes. If your bills are normal and your comfort is fine, the honest answer is usually: hold the money. The 10-15 year mark is when even code-compliant homes start showing settled batts.
Do you handle new construction insulation?
We focus on retrofit insulation for existing Denver homes. New construction insulation typically goes through your general contractor or builder, and the process is different — pricing structures, code compliance steps, and project timing all work differently for new builds. If you're working on a new build, we can refer you to a partner with new-construction experience.
Does this estimate include removal of old insulation?
Only if you select "Yes — removal needed" or "Not sure" in the input. Removal adds $1.50-$3.50 per square foot of attic. Asbestos vermiculite testing ($300-$600) and licensed abatement (when positive) are separate scopes — abatement is not included in this estimate.
Why is the cost shown as a range, not a single number?
Real Denver pricing varies with material choice (cellulose vs fiberglass), attic accessibility, time of year, and contractor backlog. A range communicates the actual uncertainty; a single number would be false precision. The free in-home estimate gives exact numbers based on what the contractor sees.
How accurate is the rebate-adjusted estimate?
Conservative. The 20-35% reduction figure assumes the standard rebate plus the Whole Home Efficiency Bonus, which requires three or more measures bundled within two years. Single-measure projects see less rebate. Income-qualified households via the Xcel IQ Program can see substantially deeper coverage.
What if I'm doing wall insulation or something else, not just attic?
This calculator is attic-specific. Wall dense-pack and crawl space encapsulation have different cost structures. The free quote covers full-home scope and gives you accurate numbers for whatever combination you're considering.