Which Longmont Insulation Rebates Does Your Address Qualify For?

Which rebate programs can your address reach?

The question is not what your mailing address says. It is which utilities bill you.

Xcel Energy provides natural gas service across this service area, including Longmont, and provides electric service in Lafayette, Louisville and Niwot. Eligibility keys off the customer's Xcel service and heating fuel, not off the town.

Efficiency Works serves residential electric customers of Longmont Power & Communications, Estes Park Power and Communications, Fort Collins Utilities and City of Loveland Utilities. In this service area that means Longmont addresses only: Lafayette, Louisville and Niwot are Xcel-electric and cannot access the program.

Inside Longmont the test is narrower still. The Efficiency Works path opens only where the project site receives residential electric service from Longmont Power & Communications, and Longmont Power & Communications does not serve the whole city. A Longmont mailing address is not the qualifier. The electric account is.

Longmont is the one town in this service area where an address can sit inside both programs' eligibility at once, because it is the only one Efficiency Works reaches.

What does each program cover?

Xcel Energy rebates three measures: attic insulation, wall insulation and air sealing. Each is paid as a share of project cost against a per-measure maximum — that is the shape of the program, and the numbers that fill the shape live on Xcel's own rebate page.

Xcel publishes two ways in. The first is homes heated with natural gas or electricity provided by Xcel Energy. The second is homes with Xcel Energy electric service using central air conditioning whose heating fuel is not provided by Xcel Energy — Xcel publishes this as a separate, reduced tier. Xcel electric service on its own is not the qualifier; which of the two paths a home falls under is a thing to confirm, not to assume.

Efficiency Works covers a longer list, and it is specific about location: attic insulation at a flat ceiling, attic knee walls that are already insulated, attic knee walls that are not, conditioned attics, cathedral ceiling, exterior wall, basement wall, conditioned crawl space, cantilever floor and floor over garage. That is ten measures, and the incentive sheet lists the two knee-wall cases separately rather than as one. Those are paid by the square foot of treated area.

Air sealing sits on a different basis inside that same program. Efficiency Works pays it as a flat amount stepped by how much measured air leakage the work actually removes. The step is decided by the testing, after the work — which is why no one can tell a homeowner in advance which step a house will land on. Air sealing is also the measure that has to come first in the work itself: insulation alone does nothing if air leaks are not sealed first.

The two programs are denominated in different units, so which one pays more depends on the measure and on the house. This page does not rank them.

What does each program require before it will pay?

Xcel requires a participating Xcel trade partner to do the work, and Xcel's own program write-up says the rebate application is only available from those trade partners — so ask who fills it in and who files it when you get the quote, rather than assuming.

Xcel also sets a qualifying minimum standard on each measure it rebates, which means the work has to qualify and not only the account. Air sealing is the measure held to a measured reduction in air leakage, and documenting that takes a blower door test before and after the work — so that testing belongs in the scope you are quoted rather than added on afterward. It is not only the air sealing rebate that rides on that number: Xcel's own program write-up makes meeting the reduction a pre-qualification for the attic and wall insulation rebates too. The one way past it is a home the first blower door reading already finds tight enough by Xcel's own measure — that home needs no air sealing and no second reading, and can go straight at the insulation measures. Those two measures are held to R-value standards as well, which Xcel publishes on its own sheet.

Efficiency Works requires an Efficiency Works Homes listed service provider, and it requires the home to complete an Efficiency Works assessment before you apply. Pre- and post-work air leakage testing and a combustion safety test also have to be in the quoted scope.

Both programs open on the utility account, which means the first thing to confirm is not the scope of the work. It is the bill. The account is what opens the door, though, not what settles the answer — each program also has requirements on the work itself, and a scope that misses them is refused on an account that qualifies. Two programs also means two sets of paperwork, two lists of approved providers and two sets of rules, because they are run by separate bodies.

One thing neither rebate settles: the R-value your permit is reviewed against. The City of Longmont adopted the 2024 International Codes effective July 1, 2026, and the figure your project is reviewed against comes from the city's building department, not from a rebate program's paperwork.

What does Efficiency Works publish about the two programs together?

Efficiency Works publishes something on this point that is worth reading in its own words. Its insulation and air sealing incentive sheet prints an “Additional incentives” table with three columns — “Efficiency Works rebate”, “Xcel rebate” and “Total potential incentives” — so the administrator of the electric-side program does publish a combined figure alongside Xcel's.

Attribute that to Efficiency Works, because that is whose statement it is. It is Efficiency Works describing its own program next to Xcel's, not a joint statement by both utilities, and not a claim this page makes about any reader's project. The values in that table are Efficiency Works' to publish and to change; read them there, in the current version of the sheet.

The access caveat travels with it. Lafayette, Louisville and Niwot cannot reach Efficiency Works at all, and inside Longmont only an address that Longmont Power & Communications actually serves can.

Where do the current rebate amounts come from?

Not from here. This page carries no rebate amounts, no per-measure caps and no percentages of project cost, and that is deliberate. Those values change, and a figure copied onto a third-party page ages the moment the program revises it. The utility's own page does not.

For current Xcel rebate amounts and program rules, see the Xcel Energy insulation and air-sealing rebates page. For Efficiency Works eligibility and current incentive values, see Efficiency Works home rebates. Eligibility may depend on which electric utility serves your address, program funding levels, and qualifying product specifications.

Verify the Xcel side with Xcel Energy, or with a contractor registered with Xcel's insulation rebate program. Verify the Efficiency Works side with Efficiency Works or with Longmont Power & Communications. Ask each body the same four things: whether your service qualifies and which eligibility path you fall under, whether your contractor is on their list, what testing they require, and what they are paying right now — including the application window and any pre-approval requirement.

One scoping note, because this page is not a survey of every program a Longmont-area home might reach: it covers the two utility rebate programs and stops there, and those two are not the whole map. Colorado runs its own Weatherization Assistance Program for income-qualified households, delivered through a local agency rather than through a utility — a route that has nothing to do with either rebate above. It runs on its own rules, its own eligibility test and its own paperwork. Ask the body that runs it, not this page.

Take the next step

What happens after you request a quote?

The first question in a rebate-aware quote is the utility question, because it decides everything downstream: which measures are covered, which testing has to be scheduled before work starts, and whose paperwork the rebate travels on. Have a recent electric bill and a recent gas bill handy for that conversation.

Get My Rebate-Adjusted Quote →

Related guides

Related services and tools