Window Replacement · Denver, Boulder, Fort Collins & the Front Range
Replacement Windows in Denver, Boulder, Fort Collins & the Front Range
Replacement windows installed by a Class C general contractor that has worked on Front Range homes since 2001 — and an on-demand client portal that shows you the permit, the delivery date, the install schedule and the inspection result without you chasing anybody for an answer.
Looking for Replacement Windows on the Front Range?
Northern Lights Exteriors installs replacement windows across the Front Range — Denver, Boulder, Fort Collins, Longmont, Loveland and Greeley. We are a Class C general contractor, not a single-trade window shop — so if opening up a window reveals rotted trim, failed flashing or siding that needs to come off, we are licensed to fix it rather than hand you a change order and a second contractor.
Most window replacement projects run one to several days on site depending on opening count and trim conditions. Your quote is broken out per opening so you can see exactly what the frame material, the glass package and the installation each cost — see our Denver window replacement cost breakdown for how those lines are built.
Every project runs through our on-demand client portal. You get access at the project meeting, before you sign anything, so you can watch how a job is actually run before committing to one.
Why Front Range Homeowners Hire Us for Window Replacement
The hard part of a window project is rarely the window. It is the not-knowing: who to call, whether the permit went in, when the units actually land, what you have paid so far, and whether it passed inspection. That is the part we built a system around.
Our on-demand client portal is custom-built and proprietary — it is not a shared inbox or a scheduling app. It tracks communication, contracts, permits, delivery and install schedules, before / production / final images, payments per trade, and inspections. Access is issued individually at the lead and project meeting, before you sign, and it stays live after completion — which matters years later when a buyer’s agent, appraiser or insurer asks for documentation on the work.
A general contractor, not a window shop
Class C general contractor, CO license #C120350. When an opening comes out and the sheathing behind it is wet, we are licensed to repair it inside the same project.
One trade or the whole elevation
Windows often want doing at the same time as siding or trim. We run siding and roofing in house, so the sequencing and the flashing details are one crew’s responsibility.
Quotes you can actually compare
Per-opening pricing with the frame, the glass package and the labor separated, so a cheaper bid can be read for what it drops rather than guessed at.
Nobody sitting in your living room for three hours
We measure, we scope, we send the number. There is no same-day-discount close and no single-brand sales pitch.
Replacement Window Materials: Vinyl, Fiberglass & Wood-Clad
Frame material sets the cost floor and the look; the glass package usually decides how the house actually feels afterwards. Front Range windows also face two conditions most of the country does not: thin air a mile above sea level, which changes how sealed units are built and shipped, and very high UV load, which is hard on finishes and on anything upholstered behind the glass.
| Material | Best for | Relative cost | The honest trade-off |
|---|---|---|---|
| Vinyl | Most Front Range homes; value-led replacements | Lower | Strong efficiency per dollar. Wider frames eat a little glass area on small openings. |
| Fiberglass | Large openings, modern elevations | Mid to higher | Rigid and dimensionally stable with slim sightlines. Costs more per opening than vinyl. |
| Composite | Homeowners wanting fiberglass performance with a warmer interior | Mid to higher | Fewer line and color options than vinyl. |
| Aluminum-clad wood | Period and architectural homes; interior joinery | Higher | Best interior appearance. Exterior clad finish is the part that has to be right. |
The glass matters as much as the frame here. Low-E coatings and gas fill are doing most of the work against Colorado’s UV and its day-to-night temperature swing, and laminated or sound-control packages are what actually quiets a house on a busy corridor. Our energy efficiency and glass package guide covers what is worth paying for and what is not.
What Does Window Replacement Cost in Colorado?
There is no honest single number, and any window company that gives you one over the phone is quoting a product rather than your house. The real drivers are the count of openings, the frame material, the glass package, whether the existing openings are square, what condition the trim and sill are in, and whether anything structural turns up once a unit is out.
What we can promise is how the number is presented: per opening, itemized, with frame, glass and labor separated so you can compare our bid against anyone else’s line for line. Full detail is on the Denver window replacement cost page, and financing options are available if you would rather spread the project.
Before you commit, check the energy-efficient window rebates currently open in Colorado — on a whole-home replacement they are worth the twenty minutes.
How a Window Installation Runs
- Walk the house and measure. Every opening measured individually, with notes on trim, sill and any water staining. This is also where we tell you if some windows genuinely do not need replacing yet.
- Itemized proposal. Per-opening pricing, frame and glass separated, with the options you actually asked about rather than a good-better-best sheet.
- Portal access and contract. Your individual portal goes live at the project meeting. Contract, scope and payment schedule all sit in it.
- Permit. We pull it. Which authority issues it depends on your address and the timelines genuinely differ — the City and County of Denver issues its own, Boulder, Longmont, Fort Collins and Greeley each run their own building department, and unincorporated addresses go through the county. The status is in the portal rather than something you have to phone about.
- Order and delivery. Manufacture lead time is the long pole on most window projects. The delivery date lands in the portal as soon as it is confirmed.
- Installation. Typically one to several days. Units set, flashed and sealed, interior and exterior trim finished, and the site cleaned each evening.
- Inspection and close-out. Final inspection result, final images and warranty documentation all filed in the portal, where they stay after the job closes.
Window Brands We Install: Andersen, Pella, Marvin & More
We are deliberately brand-agnostic. A window company that only sells one manufacturer will always find a reason that manufacturer suits your house, and on a Front Range replacement the right answer genuinely changes with the elevation, the opening size and the budget.
We install Andersen, Pella, Marvin and Anlin among others. Compare the lines side by side on our window brand comparison, which goes through what each one is actually best at, or read up on the two we are asked about most: Pella windows in Denver and Anlin replacement windows. If you want to know how a Pella installation is run end to end, that is written up too.
Still shortlisting installers? Our guide to comparing window installation contractors lists the questions worth asking every bidder — including us. It is written to be used against window contractors generally, not as a pitch, because a homeowner who has read it is a much easier customer to work with than one who has not.
Window Replacement Guides
Everything below sits under this page. Cost and contractor comparison first, then materials, then styles and brands.
- Window Replacement Cost in DenverWhat drives the number on your quote, line by line.
- Window Types & StylesDouble-hung, casement, slider, awning, picture and bay.
- Window Brand ComparisonHow the brands we install actually differ.
- Compare Window Installation ContractorsThe questions to ask every bidder before you sign.
- Vinyl WindowsThe value option for most Front Range homes.
- Fiberglass WindowsRigid frames, slim sightlines, large openings.
- Composite WindowsComposite frames and where they earn their cost.
- Aluminum-Clad WindowsWood inside, clad exterior, architectural fit.
- Double-Hung WindowsThe default replacement style on older Colorado housing stock.
- Single-Hung WindowsLower cost per opening where tilt-in is not needed.
- Pella Windows DenverThe Pella lines we install and who they suit.
- Pella Window ContractorHow a Pella installation is run start to finish.
- Anlin Window ContractorAnlin replacement windows for Front Range homes.
- Energy Efficiency & Glass PackagesLow-E, gas fill and coatings at Colorado altitude.
- Energy-Efficient Window RebatesRebate and incentive programs worth checking first.
Where We Install Replacement Windows Across the Front Range
We install replacement windows across the northern Front Range — Denver and Boulder, Fort Collins, Longmont, Loveland and Greeley, and the towns between them. Crews run out of Fort Lupton, so the whole corridor from Denver to the Wyoming line is local work for us, not a travel job.
Cities we serve
Every city below has its own replacement-window page with local permit notes, typical housing stock and recent work. Start there if you already know where you are.
Denver metro
- Denver
- Commerce City
- Northglenn
- Thornton
- Westminster
- Broomfield
- Golden
- Greenwood Village
- Cherry Hills Village
Boulder County & the US-36 corridor
Northern Colorado
Carbon Valley, I-25 north & the foothills
What differs across the corridor
Two hundred feet of elevation and forty miles of latitude change what a window has to do, which is why we specify by address rather than by catalog.
- Denver and the metro suburbs. Pre-war brick bungalows and Denver Squares where the openings are rarely square any more, post-war ranches through the south and south-west, and newer east-side builds whose original builder-grade units are reaching the end of their sealed-unit life. Full-frame versus retrofit is a live question here more than anywhere else on the corridor.
- Boulder County and the foothills. Elevation climbs fast west of the diagonal, and with it the UV load and the day-to-night swing that work a sealed unit hardest. Foothills addresses can also carry wildfire-code requirements at the openings and the ventilation around them, set at county level and varying by parcel.
- Longmont, the Carbon Valley and the north metro. Subdivisions built from the 1990s onward are hitting first seal failure across whole streets at once, which is why the foggy-pane call arrives here in waves. Open-plains wind also drives rain at the glass harder than anything in the metro.
- Loveland, Greeley and Fort Collins. The northern end sits in the part of Colorado that takes the most hail. Hail is mostly a roofing story, but it cracks glass and pits frames on exposed elevations, and a window claim often arrives attached to a roof claim.
Outside the city limits we work across the Front Range — see all service areas, or the Denver service-area page for how we work locally. Recent window work is in the project gallery.
Replacing a patio door too? Andersen, Pella, Marvin and Anlin all make sliding patio doors to match the windows above, and a patio door is usually the largest single source of heat loss on that wall — so it is worth ordering in the same package. See exterior door installation and replacement for entry, patio, sliding, storm and garage doors.
Window Replacement FAQs
How much does window replacement cost in Colorado?
It depends on the number of openings, the frame material, the glass package and what condition the existing openings and trim are in. We price per opening and separate frame, glass and labor so the quote can be compared line by line against any other window company. The cost page walks through each driver.
Who is the best window replacement company on the Front Range?
Judge it on three things rather than on a brand name: whether the company is a licensed general contractor that can handle what is found behind the window, whether the quote is itemized per opening, and whether you can see permit, schedule and inspection status without phoning anyone. Northern Lights Exteriors has worked the Front Range since 2001, holds Colorado Class C general contractor license #C120350, and runs every project through an on-demand client portal.
How long does window replacement take?
Manufacture lead time is usually the longest part; the installation itself is typically one to several days depending on how many openings there are and how much trim and finish work is involved.
Do I need a permit to replace windows in Colorado?
Replacement windows generally require a permit across the Front Range, and the issuing authority changes with the address — the City and County of Denver issues its own, while Boulder, Longmont, Fort Collins and the smaller towns each run their own building department. We pull the permit as part of the project and the status sits in your portal.
Are vinyl or fiberglass windows better for a Colorado home?
Vinyl gives the strongest efficiency per dollar and suits most Front Range homes. Fiberglass is worth the step up on large openings, on modern elevations where slim sightlines matter, and where long-term frame stability is the priority. On smaller openings the wider vinyl frame costs you a little glass area, which is the trade-off worth knowing about.
Will new windows actually reduce street noise?
They can, materially — but the glass package does that work, not the frame. Laminated and sound-control packages plus a properly sealed installation are what quiet a house on a busy arterial. Standard double glazing on its own will not.
Do you replace just a few windows, or is it whole-home only?
Either. Replacing the worst elevation first is a perfectly reasonable way to run it, and during the walk-through we will tell you which openings can wait.
What happens if there is damage behind the old window?
This is the main reason to use a general contractor rather than a window-only installer. If the sheathing, framing or flashing behind an opening turns out to be wet or rotted, we are licensed to repair it within the same project instead of stopping work and referring you on.
Have a question we didn’t cover? Browse 36 straight answers by frame type — vinyl, fiberglass, wood-clad, glass packages, egress, and hail claims — in our Colorado Window Questions & Answers hub.
Get a Window Replacement Quote
Tell us how many openings you are looking at and what is bothering you about the current windows — drafts, noise, condensation between the panes, or units that no longer lock. We will measure, scope it honestly, and send an itemized number.
Request Your Free Estimate → 📞 (303) 776-5263
Prefer email? Reach us at office@nlexteriors.com. Ask about financing when we walk the property, and about who you are actually hiring if you like to know that first.
