What window and door rebates pay in Fort Collins
We read Efficiency Works' windows and doors sheet and its rebate page on October 5, 2026. The program serves residential electric customers of Fort Collins Utilities, and also Estes Park, Longmont and Loveland.
Windows and sliding doors, Tier 2
ENERGY STAR version 7 for the Northern climate zone.
Windows and sliding doors, Tier 1
ENERGY STAR version 6 for the Northern climate zone.
Exterior doors
ENERGY STAR certified for the Northern climate zone.
Bundling bonus
If you also install a heat pump within six months of the windows or doors. Water heaters do not count.
Rental bonus
Rental properties served by Fort Collins Utilities get twice the retrofit rebate, with a 12-month lease and approval before work.
Federal tax credit (25C)
The credit for windows and doors ended for spending after December 31, 2025.
Working it out
Efficiency Works' own example is 20 windows of 20 square feet each, which is 400 square feet. At Tier 1 that is 400 x $3.75 = $1,500. At Tier 2 it is 400 x $5.00 = $2,000. Replace a patio slider of 40 square feet with a Tier 2 unit and that line is $200. The sheet notes no known 2026 rebate stacking for windows. Packages over $2,500 need approval before work begins.
What Fort Collins homes look like
The American Community Survey (2020 to 2024) counts 74,558 homes in Fort Collins. About 52% of households own and 48% rent. About 52% of homes are detached houses, and only 31% were built before 1980, while 37% were built in 2000 or later.
With fewer old homes than Denver or Boulder, windows are not an obvious first step for many Fort Collins owners. The rebate is a reason to look at the glass you have, not a reason to replace windows that work.
How the rebate is worked out
The rebate is the glass or door area times the rate. Area is the area of the product, so measure the openings you plan to change and ask your installer for each unit's size. The sheet's example of twenty 20-square-foot windows is a big whole-house job. A few windows or one slider would earn a few hundred dollars.
The rules
Work must be done by an Efficiency Works listed service provider on a home at least a year old, with new products. The window must meet the ENERGY STAR Northern climate zone requirement, version 6 for Tier 1 and version 7 for Tier 2. A combustion safety test is required, which checks gas appliances for safe venting. You apply within 45 days of finishing, and a package above $2,500 needs approval first.
What Fort Collins heats with
About 66% of Fort Collins households heat with utility gas and 31% with electricity. The window rebate does not depend on your fuel. If your windows are drafty and you are planning a heat pump, the $2,000 bundling bonus applies when you do both within six months.
Cold in Fort Collins
Our climate file, built from ten Januaries (2015 to 2024), gives Fort Collins an average January low of about 16°F and a coldest day near minus 28°F. Ask your installer for each window's rating and for the ENERGY STAR version, since the higher rate needs version 7.
How to claim Fort Collins window and door rebates
- Check that Fort Collins Utilities is your electric company.
- Measure the openings and ask for each unit's ENERGY STAR version.
- Choose an Efficiency Works listed service provider.
- Plan any heat pump within six months of the windows for the $2,000 bonus.
- Apply within 45 days of finishing, after the combustion safety test.
Common questions
How much does Fort Collins pay for windows?
$3.75 per square foot for ENERGY STAR version 6 windows and sliding doors, $5.00 for version 7, and $3.75 for exterior doors, from Efficiency Works' 2026 sheet.
Is a combustion safety test required?
Yes. The sheet requires a combustion safety test for windows and doors.
Do other Colorado cities have a window rebate?
We could not confirm a utility window rebate for Denver, Aurora, Boulder or Colorado Springs, so we do not list one.
Can I combine with other rebates?
The sheet says there is no known 2026 stacking for windows, but the $2,000 bundling bonus applies if you also install a heat pump within six months.
Is there a federal tax credit?
Not for 2026. It ended for spending after December 31, 2025.
What to do next
See our Fort Collins insulation page and Fort Collins heat pump page for the other pieces of the bonus, or the Fort Collins rebate hub.
By Sam Menard. Sources, last read October 5, 2026: Efficiency Works home rebates (Fort Collins Utilities), Efficiency Works windows and doors sheet, IRS residential clean energy credit. All Fort Collins rebates → Every Efficiency Works home rebate →