If you are pricing out attic insulation in the Denver metro, here is the short answer: most homeowners in Lakewood and across the Front Range pay around $2,222 for a typical attic job, with the majority of projects landing between $1,799 and $2,645. On a per-square-foot basis, installed insulation runs from about $1.00 for blown-in fiberglass to $5.00 for closed-cell spray foam. Where your project falls depends on the material, how much depth you need to hit code, whether old insulation has to come out, and how tricky your attic is to work in.
This guide breaks down the real 2026 numbers for Denver-area homes, shows how cost scales with attic size, and explains the Xcel Energy rebates and Colorado programs that can knock a serious chunk off your final bill. If you would rather skip straight to a firm number, you can book a free attic assessment or call AtticPro at 720-343-2337.
Attic Insulation Cost at a Glance
The single biggest driver of price is the material you choose. Blown-in options are the value pick for most open attic floors, while spray foam costs more but seals and insulates in one step for tricky areas. Here is how the four main materials compare on installed cost, R-value per inch, and where each one shines.
| Type | Installed cost / sq ft | R-value per inch | Best for |
|---|---|---|---|
| Blown-in fiberglass | $1.00 – $1.70 | ~2.2 – 2.7 | Budget-friendly coverage on open attic floors |
| Blown-in cellulose | $1.10 – $1.80 | ~3.2 – 3.8 | Better R-value per inch and denser coverage on open floors |
| Open-cell spray foam | $1.70 – $2.90 | ~3.5 – 3.7 | Sealing and insulating roof decks and irregular spaces |
| Closed-cell spray foam | $3.00 – $5.00 | ~6.0 – 6.5 | Maximum R-value in tight spaces, knee walls, moisture control |
Notice how the R-value per inch changes the math. Closed-cell spray foam costs the most per square foot, but it delivers more than double the R-value per inch of blown-in fiberglass, so you need far less depth to hit your target. On an open attic floor where you have room to pile up material, blown-in cellulose or fiberglass almost always wins on total cost.
Cost by Attic Size
Square footage is the other half of the equation. A compact bungalow attic and a sprawling ranch or two-story will land in very different places even with the same material. The ranges below assume you are insulating to Denver’s recommended level and cover the spread from economical blown-in up through premium spray foam.
| Attic size | Blown-in (fiberglass / cellulose) | Spray foam (open / closed cell) |
|---|---|---|
| Small (~500 sq ft) | $500 – $900 | $850 – $2,500 |
| Average (~1,000 sq ft) | $1,000 – $1,800 | $1,700 – $5,000 |
| Large (~1,500+ sq ft) | $1,500 – $2,700+ | $2,550 – $7,500+ |
For context, the Denver-metro average attic insulation job comes in around $2,222, which lines up with an average-sized attic getting a quality blown-in installation or a partial spray foam application. Most homeowners we work with in Lakewood, Wheat Ridge, Arvada, and the surrounding suburbs fall in that $1,799 to $2,645 window.
As a Lakewood-based company, we see the same pattern across Jefferson County and the west Denver suburbs: many homes built before modern energy codes still sit at R-19 or less, which is exactly why an upgrade pays for itself so quickly here. Whether you are in Lakewood, Wheat Ridge, Golden, or Arvada, the ranges above hold; the main variable is how much depth you need to reach R-49 or R-60.
What Drives Your Attic Insulation Cost
Two homes on the same street can get very different quotes. Here is what moves the number.
Target R-value and depth
Denver sits in IECC Climate Zone 5, and both the U.S. Department of Energy and ENERGY STAR recommend R-49 to R-60 for attics here. R-49 is the cost-effective minimum and R-60 is the optimal target. The higher you go, the more material and labor you pay for, but the more you save on heating. If your attic is under-insulated (many older Denver homes sit at R-19 or less), building it up to R-49 or R-60 is where the comfort and savings come from.
Material choice
As the tables show, material can swing your per-square-foot cost by 3x to 5x. Blown-in is the workhorse for open attics; spray foam is the specialist for sealing and hard-to-reach spots.
Whether old insulation needs removal
If your existing insulation is clean and dry, we can often top it up and skip removal entirely. If it is contaminated, matted, or damaged, removal adds roughly $1.50 to $2.00 per square foot before new material goes in.
Adding air sealing
Insulation slows heat transfer, but it does not stop air leaks around can lights, top plates, and penetrations. Pairing air sealing with insulation is a modest add-on that dramatically improves performance, and it unlocks a separate Xcel rebate (more on that below).
Attic access and complexity
Low pitches, tight hatches, lots of ductwork, or knee walls all slow the job down and can raise the price. A walk-up attic with clear decking is cheaper to service than a cramped crawl space full of obstructions.
Blown-In vs. Spray Foam: Cost & When Each Makes Sense
This is the decision most Denver homeowners are really trying to make, so let us be direct about it.
Blown-in insulation is the best value for a standard open attic floor. At $1.00 to $1.80 per square foot, it fills every gap and joist cavity quickly and hits R-49 or R-60 without breaking the budget. For the vast majority of homes, our blown-in insulation service is the right call, and it is why the typical Denver attic job lands near that $2,222 average rather than the top of the range.
Spray foam earns its higher price in specific situations: knee walls, vaulted ceilings, roof decks, rim joists, and any spot where you need to air-seal and insulate at the same time. At $1.70 to $5.00 per square foot it is a bigger investment, but nothing matches it for sealing complex geometry. Many projects use a smart combination, spray foam where it counts and blown-in across the open floor. Explore our spray foam insulation and air sealing options to see which mix fits your home.
How Much Does Insulation Removal Cost?
Removal typically adds about $1.50 to $2.00 per square foot on top of your new insulation. It covers the labor, equipment, and disposal to vacuum out old material and haul it away.
The good news: removal is often not necessary. If your current insulation is dry, clean, and simply too thin, we can add new material right over the top and bring you up to code. You only need full insulation removal when the old stuff is compromised, usually from rodent infestation, mold, or water damage. If critters have been living up there, removal plus rodent-proofing is the sanitary reset that protects your new investment. During your assessment we will tell you honestly whether removal is needed or whether a top-up will do the job for less.
Xcel Rebates & Colorado Programs That Cut Your Cost
The sticker price is not what you actually pay. Colorado homeowners have real rebate money on the table, and it can turn a $2,000-plus project into a much smaller net cost.
- Xcel Energy insulation rebate: up to $1,250.
- Xcel Energy air sealing rebate: up to $875.
- Heat pump bonus: an extra $600 when insulation and air sealing are paired with a qualifying heat pump.
These bonus rebates are for homes heated with Xcel natural gas, and the work must be completed by a participating contractor. You can review the current terms directly on the Xcel Energy insulation and air sealing rebates page. AtticPro is set up to handle these rebates for you.
Beyond Xcel, the state offers help too. The Colorado Energy Office runs a Weatherization Assistance Program that provides free efficiency upgrades to income-qualified households, plus a broader Home Energy Rebates program. It is worth checking whether you qualify before you pay out of pocket.
One important note for 2026: the federal 25C energy-efficiency tax credit expired on December 31, 2025 under the One Big Beautiful Bill Act, so it is not available this year. Do not budget around it. The Xcel and Colorado programs above are the current levers that actually lower your cost.
To make it simple, AtticPro applies eligible rebates directly to your invoice so you see the savings up front, and we offer $0-down financing if you would rather spread the cost over time. See our rebates and savings details and financing options for the full picture.
Get an Exact Price for Your Attic
Every attic is different, and the only way to get a number you can trust is to have someone measure your space, check your current R-value, and look for air leaks. That is exactly what our free assessment does, with no obligation. Book your free attic assessment online or call 720-343-2337 and we will give you a firm, itemized quote with rebates already factored in.
Not sure which type of insulation is right for your home? See our attic insulation comparison guide for Colorado homes to weigh the options before you decide.
Attic Insulation Cost FAQs
Is attic insulation worth it in Denver?
Yes. Denver’s Climate Zone 5 winters are heating-dominated, and an under-insulated attic is where most of that heat escapes. Bringing your attic up to R-49 or R-60 improves comfort year-round and pays for itself through lower energy bills, especially once rebates reduce your upfront cost.
How much can I save on my Xcel bill?
Savings vary by home, but proper attic insulation and air sealing are among the highest-return efficiency upgrades you can make. The bigger the gap between your current R-value and the R-49 to R-60 target, the larger your heating and cooling savings will be.
Do I need to remove old insulation?
Usually not. If your existing insulation is dry and clean, we can add new material on top to reach code. Removal (about $1.50 to $2.00 per square foot) is only necessary when the old insulation is contaminated by rodents, mold, or water damage.
Does attic insulation qualify for rebates?
In most cases, yes. Xcel Energy offers up to $1,250 for insulation and up to $875 for air sealing for eligible gas-heated homes when the work is done by a participating contractor, with an extra $600 bonus if paired with a qualifying heat pump. Income-qualified households may also access free upgrades through the Colorado Energy Office.
What is the cheapest attic insulation option?
Blown-in fiberglass is the most budget-friendly at $1.00 to $1.70 per square foot installed. Blown-in cellulose costs slightly more but delivers a higher R-value per inch, which can make it the better value once you factor in performance.
Cost and rebate figures in this guide are 2026 estimates, subject to program terms and eligibility, and will vary by home. Contact us for a quote specific to your attic.
