Why insulate
Why do Longmont homes need insulation attention?
Longmont's housing stock skews older than the other three towns in this service area. Roughly 4 in 10 Longmont housing units predate 1980, and the median home dates to about 1991 (Census Bureau American Community Survey 5-year estimates, 2020-2024) — old enough that original attic insulation, where it exists at all, is a reasonable bet to be running well under today's targets.
What makes Longmont different from a typical Front Range insulation market isn't the housing — it's the utility map. Longmont Power & Communications, the city's own municipal electric utility, doesn't cover the whole city. Verified against Colorado's official electric-utility-territory data: roughly 61% of Longmont's area is LPC electric; the rest splits between Xcel, Poudre Valley REA, and United Power, concentrated on the city's west and east edges respectively. Two homes a few blocks apart can have different electric utilities, and only one of them can access the Efficiency Works rebate described below.
The practical result: every Longmont insulation quote should include a check of which utilities actually serve the address, not just which town it's in. Xcel's gas-and-electric rebate applies citywide regardless of which electric utility a home has. The Efficiency Works rebate does not — it requires LPC electric service specifically, and the only way to know for certain is to check the electric bill.
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.”
Rebates & credits
What rebates can Longmont homeowners claim?
Xcel Energy — applies to every Longmont address, regardless of electric utility:
- 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.
Efficiency Works — Longmont Power & Communications electric customers only, not every Longmont address:
- Efficiency Works Retrofit Rebate — $1.16 per square foot for most insulation measures, $0.77 per square foot for flat-ceiling attic insulation, and a tiered flat payment for air sealing based on measured reduction in air loss from a blower door test (above 15% pays $310, above 25% pays $460, above 33% pays $620, above 50% pays $770). Requires an Efficiency Works assessment first, a listed service provider, and applies only to residential electric customers of Longmont Power & Communications — check your electric bill to confirm.
Boulder County EnergySmart — income-qualified only as of January 1, 2026:
- Boulder County EnergySmart — for households at or below 100% of area median income, 50% of project cost up to $2,000 per year, subject to R-60 attic / R-19 wall / R-30 sub-floor minimums and required blower-door testing. Standard (non-income-qualified) rebates ended January 1, 2026.
These are three separate programs from three separate sources. Nothing published by any of them states that a single project can combine more than one — ask your contractor to confirm which apply to your specific address before assuming a total.
According to Efficiency Works (Platte River Power Authority program, for Longmont Power & Communications electric customers), “Efficiency Works pays $1.16 per square foot for most insulation measures (conditioned crawl space, basement wall, cantilever floor, exterior wall, cathedral ceiling, conditioned attic) and $0.77 per square foot for flat-ceiling attic insulation, available only to residential electric customers of Longmont Power & Communications.”
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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 which programs your specific address qualifies for. Xcel and Efficiency Works are separate programs with separate paperwork, and not every address qualifies for both. (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. Longmont Power & Communications electric customers may separately qualify for an Efficiency Works rebate — check your bill to see which utility serves your address. Boulder County EnergySmart pays a third, income-qualified-only rebate as of January 1, 2026.) (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 Longmont homeowners ask most about insulation and rebates?
How do I know if I have Longmont Power & Communications or another electric utility?
Check your electric bill — the utility name is on it. LPC bills come from the City of Longmont; if your bill instead comes from Xcel Energy, Poudre Valley REA, or United Power, you have a different electric provider and the Efficiency Works rebate described on this page does not apply to your address. Xcel's gas-and-electric insulation rebate applies regardless of which of the four serves your address.
Do the Xcel and Efficiency Works rebates add together?
We can't say that they do. Xcel and Efficiency Works are separate programs, from separate sources, with no published rule stating whether a single project can claim both. Efficiency Works publishes a table showing both figures side by side, but a side-by-side table isn't a statement that they stack — treat that as unconfirmed until your contractor or the programs themselves settle it for your specific project, and don't assume the combined number until they do.
Should I do this if my Longmont home was built after 2010?
Probably not yet. Post-2010 Longmont homes were built to recent code, with attic insulation well above the pre-1990 baseline. If your bills are normal and comfort is fine, hold the money. The 10-15 year mark is typically when settled batts and unsealed penetrations start costing you — that's when it's worth another look. We'll tell you straight when we look at it.
What does Longmont's Efficiency Works rebate actually pay?
For LPC electric customers only: $1.16 per square foot for most insulation measures, $0.77 per square foot for flat-ceiling attic insulation, and a tiered flat payment for air sealing based on measured leakage reduction — $310 above 15%, $460 above 25%, $620 above 33%, $770 above 50%. Incentives are capped at 100% of project cost and require an Efficiency Works assessment first.
Do you serve all of Longmont?
Yes — every Longmont neighborhood and ZIP code, plus Lafayette, Louisville, 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 Longmont?
- Old Town Longmont
- Prospect New Town
- Southmoor Park
- Renaissance
- Quail Ridge
- Sunset Golf Course area
- Downtown Longmont
- 80501
- 80503
- 80504