The calculator
Run the spray foam vs blown-in vs hybrid comparator
Pick the area, square footage, your priorities, and budget tier. The comparator runs all three approaches (spray foam, blown-in, and the flash-and-batt hybrid) and ranks them against your stated goals.
Your project
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 spray foam vs blown-in vs hybrid comparator work?
The comparator scores each approach against your stated goals (max R-value, air sealing, low cost, long-term performance, sound reduction), then applies a budget modifier and an area-specific bias (rim joist work favors foam regardless of budget). The winner is whichever scores highest.
No primary source publishes a Denver-specific installed cost per square foot for spray foam, blown-in, or hybrid, so this tool ranks relative cost tier — spray foam highest, hybrid roughly 60-70% of foam, blown-in lowest — rather than computing a dollar range. Removal of existing material adds proportionally more to foam and hybrid (full removal required) than to blown-in (often installs over existing material). The free in-home estimate prices your specific project.
In practice, reaching the penetrations in the ceiling plane means the old loose-fill comes out first — you cannot seal what you cannot see or reach.
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.
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According to the Building America Solution Center, “loose-fill cellulose will settle from 10 to 20 percent over time due to gravity and vibration.”
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.
When does spray foam actually earn its premium?
Three scenarios: rim joists and small targeted air-sealing applications (premium per sq ft is small in absolute terms); vaulted ceilings or conditioned-attic conversions (foam adheres to roof deck, blown-in can't); and homes with chronic cold-spot or wind-infiltration issues that air sealing alone won't solve. For typical attic top-ups in pre-1990 Denver homes, blown-in is usually the right call.
What is flash-and-batt hybrid?
Two-layer install: closed-cell spray foam goes on the deck (typically 1.5-2 inches for ~R-13 and continuous air sealing), then blown-in cellulose or fiberglass batts fill the rest of the cavity to reach the R-value target. You get the foam's air-sealing benefit at the deck — where most attic-plane leakage occurs — at roughly 60-70% of full-foam cost.
Does spray foam off-gas or have indoor air quality issues?
During cure, yes — standard practice is to vacate the home for 24 hours after install with active ventilation. Modern formulations cure faster than 15+ years ago, but the chemistry is real. Once cured, no off-gassing. Reputable installers schedule cure time and ventilation explicitly. People with respiratory sensitivities should extend the vacate window 48-72 hours.
Can I use spray foam without removing existing insulation?
No. Foam adheres to the structural deck and surrounding framing — it can't be applied over loose-fill or batt material because the bond fails. Plan on removal as a separate scope before any foam install. The exception is rim joist work, where there's typically no existing insulation to remove.
Does the comparator account for Xcel rebate differences between approaches?
Indirectly. All three approaches qualify for the Xcel Insulation and Air Sealing Rebate when meeting program R-value targets. Spray foam often delivers higher R-values per inch, which can affect rebate amount. The Whole Home Efficiency Bonus is a 25% bonus on all standard rebates when three or more qualifying measures are completed within two years of enrolling. Run the Rebate Eligibility Checker for a more detailed breakdown.