Why insulate
Why do Louisville homes need insulation attention?
Louisville's housing-age numbers are genuinely mixed, and not in the usual way. Close to half of Louisville housing units (46.0%) predate 1990, and the median home dates to about 1991 (Census Bureau American Community Survey 5-year estimates, 2020-2024) — on paper, one of the older housing stocks in this service area. But the December 2021 Marshall Fire destroyed several hundred Louisville homes, concentrated in 1970s-80s subdivisions, and much of that lost stock has been rebuilt since. A home that reads as 'built in the 1970s' in some records may in fact be a 2022-or-later rebuild sitting on an older lot.
What that means practically: we won't assume your Louisville home's age from its neighborhood or its lot without asking. If your home was rebuilt after the fire, it was very likely built to a recent code edition with insulation well above older baselines — a different conversation than a pre-1990 original-stock home.
Utility-wise, Louisville is simpler than Longmont: Xcel Energy is confirmed as both the gas and electric utility here, so there's one insulation rebate program to check, not two.
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 5.”
Rebates & credits
What rebates can Louisville homeowners claim?
Xcel Energy — the gas and electric utility here:
- Xcel Energy Insulation and Air Sealing Rebate — 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 when the heating fuel is Xcel gas. A reduced tier ($15–$60 per measure) applies to Xcel electric customers whose heat is not Xcel gas. Requires a participating contractor and a blower door test documenting at least a 20% reduction in CFM50.
Xcel's rebate excludes new construction, additions, garages, sheds, and mobile homes. Ask your contractor to confirm your project scope and heating fuel qualify before assuming a figure.
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.”
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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 whether your project qualifies for Xcel's gas-heat tier or the reduced electric-only tier. (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 here.) (4) Removal scope — older homes often need old insulation removed before new install. If a quote skips all four, get another quote.
Frequently asked
What do Louisville homeowners ask most about insulation and rebates?
My home was rebuilt after the Marshall Fire — do I still need this?
Probably not yet, if the rebuild was recent. Homes rebuilt after the December 2021 Marshall Fire were built to a recent code edition, with attic insulation well above older baselines. If your bills are normal and comfort is fine, hold the money — this page is aimed at Louisville's pre-1990 original-stock homes, not fire rebuilds.
How do I know if my Louisville home is original stock or a rebuild?
Check your county assessor record for the actual year built and any recent permit history — that's more reliable than assuming from the neighborhood or the lot. A 2022-or-later built date means recent code, not the older baseline this page discusses.
Does Louisville have its own separate electric-utility rebate, like Longmont does?
No. Louisville is confirmed Xcel-electric — Xcel Energy serves both gas and electric here, so there's a single insulation rebate program to check. Longmont's situation (a second, Longmont Power & Communications-only rebate) doesn't apply in Louisville.
What does Xcel's rebate actually pay for a Louisville attic project?
For gas-heat customers: 30% of project cost, up to $500 for attic insulation, with a 1.5x multiplier applied when the heating fuel is Xcel gas. A reduced tier applies if your heat isn't Xcel gas. Xcel requires a participating contractor and a blower door test documenting at least a 20% reduction in CFM50.
Do you serve all of Louisville?
Yes — all of Louisville, plus Longmont, Lafayette, and Niwot. Service areas listed at the bottom of this page show where we work regularly.
Service area
Where do you provide insulation services in and around Louisville?
- Louisville
- Old Town Louisville
- greater Louisville area