The calculator
Run the attic insulation cost calculator
Enter your attic square footage, current insulation level, and target R-value. The calculator scopes your project — no primary source publishes a Denver-specific installed cost per square foot, so this tool does not compute a dollar estimate.
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 sets a minimum ceiling insulation R-value of R-60 in Climate Zone 5 under Table R402.1.3, and Section R402.2.1 allows R-49 to satisfy that requirement only where the full height of uncompressed R-49 insulation extends over the wall top plate at the eaves.
How this works
How does the attic insulation cost calculator work?
No primary source publishes a Denver-specific installed cost per square foot for insulation, so this tool scopes the project — square footage, current insulation, target R-value, removal need, air sealing — instead of computing a dollar range from a borrowed rate. Targeting R-60 — the Climate Zone 5 code requirement — needs about 15% more material than stopping at R-49.
Rebates are separate from the scope. Xcel's insulation and air sealing rebates are capped per measure, arrive as checks after application rather than as invoice discounts, and require an Xcel participating contractor. The free in-home assessment turns this scope into an actual price.
According to Xcel Energy, the participating-contractor symbol marks a program that requires customers to use an Xcel Energy participating contractor to install the equipment or make the improvement.
Get a quote
Get a Quote Based on Your Numbers
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 2021 IECC sets a ceiling minimum of R-60 in Climate Zone 5 (Table R402.1.3); R-49 qualifies only where uncompressed insulation extends full-height over the top plate at the eaves. (2) Air sealing scope — insulation and air sealing work together; sealing the leaks first is what lets the insulation do its job. If a quote skips both, get another quote. The federal IRA Section 25C tax credit ended December 31, 2025, and Colorado's HEAR single-family program is now closed for both Region 1 (the Front Range) and Region 2. Xcel Energy programs are the ones still paying on Denver-area insulation projects in 2026.
Related guides
Related services and calculators
According to ENERGY STAR's Seal and Insulate program, “EPA estimates that homeowners can save an average of 15% on heating and cooling costs (or an average of 11% on total energy costs) by air sealing their homes and adding insulation in attics, floors over crawl spaces and basements.”
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 the code edition in force at the time, which set a lower ceiling minimum than the R-60 the 2021 IECC requires — so a newer home can be code-legal as built and still sit short of today's target. 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 tool include removal of old insulation?
It flags removal as part of the scope if you select "Yes — pre-1990 home, contamination, or settled material" or "Not sure" in the input. Asbestos vermiculite testing and CDPHE-certified abatement (when positive) are separate scopes — not included here.
Why won't this tool give me a Denver price?
Because no primary source publishes one. Utility program pages, government sources, and IECC code tables publish requirements and rebate terms in detail — none of them publishes what insulation costs in Denver. Printing a figure would mean inventing it or lifting it from an aggregator, and this site does not use aggregators for anything. Scoping the project honestly is the version that survives being checked.
Does this tool subtract rebates?
There's no dollar figure to subtract rebates from. Xcel's insulation and air sealing rebates are capped per measure, are paid by check after your application is approved, and require an Xcel participating contractor — so the amount depends on the scope your contractor actually files and on program terms current at the time of the work. Your contractor confirms the current amounts; we do not estimate them here.
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 scopes entirely. The free quote covers full-home scope for whatever combination you're considering.