Window Installation Service

Window Installation Service in O'Fallon, MO

Name: Keller Window & Door LLC
Address: O'Fallon, MO, US
Telephone: (314) 399-2001
Price range: $$$
Rating: 5.0

5 specialized services available

We install and replace windows with precision and care. Our team handles everything from single-window upgrades to full-home window replacement. Each installation meets factory standards for fit, seal, and performance. We work in O'Fallon, Chesterfield, St. Peters, Wentzville, Wildwood, Ellisville, Creve Coeur, St. Charles, Ladue, Oakville, University City, Ballwin, Town and Country, and Maryland Heights.

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Professional window installation in a residential home

Window Installation Service

Serving O'Fallon, MO and the Florida Panhandle

Since 2015 Years Local

Free Estimates

5-Year Warranty

Services

Window Installation Service Services in O'Fallon, MO

A freshly installed replacement window on the exterior of a single-family home in O'Fallon, Missouri, with clean trim lines and a tight seal against the frame. The surrounding siding shows no gaps or damage, reflecting a completed professional window installation.

Window Installation

Keller Window & Door LLC provides professional window installation for O'Fallon homeowners looking to improve comfort and curb appeal.

Reduced heating and cooling loss through properly sealed, well-fitted window installations
Lower outdoor noise entering your O'Fallon home after old, worn frames are replaced
Improved curb appeal and resale value on a home in O'Fallon's competitive housing market

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A freshly installed double-hung replacement window on the exterior of a single-family home in O'Fallon, Missouri, with clean trim lines and a tight frame seal. The surrounding siding shows no gaps or damage, reflecting a complete professional installation.

Window Replacement

Keller Window & Door LLC provides professional window replacement for O'Fallon homeowners who want better comfort and lower energy costs.

Reduced heat loss and heat gain through properly sealed, energy-efficient windows
Lower outdoor noise entering your O'Fallon home from street and yard
Frames that resist warping, rot, and moisture common in Missouri's humid summers

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A newly installed single replacement window on the exterior of a residential home in O'Fallon, Missouri, with clean trim lines and a tight frame seal. The surrounding siding shows no damage, and the window glass is clear with no fogging or visible gaps.

Single-Window Installation

Keller Window & Door LLC installs single windows for O'Fallon homeowners who need one opening replaced.

Stops drafts at one problem opening without a full-house project
Reduces heat and humidity transfer during O'Fallon's hot, humid summers
Improves operation so the window opens, closes, and locks as it should

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A two-story O'Fallon, Missouri home with newly installed replacement windows across all front-facing openings, showing clean white frames and uniform glass against a brick exterior. Close-up detail of a finished window sill and sealed frame on a 1990s-era suburban home.

Full-Home Window Replacement

Keller Window & Door LLC provides full-home window replacement for O'Fallon homeowners ready to stop drafts and cut energy loss.

Stops cold-air drafts and heat loss tied to O'Fallon's wide seasonal temperature swings
Removes condensation and moisture buildup between panes that signals seal failure
Consistent frame style and color across every room when all windows are replaced together

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A newly installed replacement window on the exterior of a residential home in O'Fallon, showing clean frame lines, tight weathersealing, and updated hardware. Interior view reflects clear, unfogged glass with no visible gaps at the frame edge.

Window Upgrade

Keller Window & Door LLC provides professional window upgrade services for homeowners in O'Fallon.

Reduced air leakage at the frame cuts heating and cooling loss through the window opening
Properly sealed glass units stop interior condensation and fogging between panes
Upgraded frames resist warping and swelling through O'Fallon's humid summers and cold winters

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We Serve

Why Choose Us

What sets us apart for Window Installation Service

Andersen Certified Contractor and Elite Certified distinction

Former Andersen employee owner with 30 years field experience

Factory-level installation precision and quality standards

Transparent pricing and clean workmanship

Appointment-only service for focused attention

Ready to get started?

Seen the work. Ready to talk about your project?

Call (314) 399-2001

FAQ

Common Questions About Window Installation Service in O'Fallon, MO

Straight answers to the questions homeowners ask before hiring a local contractor.

Do you install windows in Chesterfield and nearby areas?

Yes, we install windows throughout the St. Louis area including Chesterfield, O'Fallon, St. Peters, and 11 other communities. Call us to schedule an appointment.

What's the difference between window installation and replacement?

Installation is for new windows in new openings. Replacement removes old windows and fits new ones into existing frames. We do both.

Can you install just one window or do you require full-home jobs?

We install single windows or entire homes. There's no minimum job size.

How do I schedule a window installation appointment?

Call us at 314-399-2001. We work by appointment Monday through Friday, 8:30 a.m. to 4:30 p.m.

Still have questions?

Call us directly. Real answers, no scripts.

Call (314) 399-2001

Client Reviews

What St. Charles County homeowners say.

5.0

11 Google reviews

Worked with us?

Leave a Review

I highly recommend Keller! The windows which I had replaced in my home are wonderful and I was very pleased with working with Keller. John Keller was very professional and honest in his recommendations for my windows as well as giving me a fair price for quality windows and workmanship. This is the only company to go with for window and door installation!

It was a pleasure working with John and his crew. They were helpful and did an excellent job with installation. I would use them again and recommend to anyone in need of a new patio door or other items they sell. Brenda Wilson

I love my new windows! What makes them even better is that the whole experience with Keller was very positive! I wish all contractors worked like John does. He was quick to reply for an estimate. His price was very fair. He came to install the windows when he said he would and he did what he said he would. (He actually did a little extra.😊)John and his crew were respectful, efficient, friendly. They protected my floors. They cleaned up after themselves. And they didn’t try to charge me extra for unforeseen issues. They wanted me to be happy and I AM. VERY. My new Andersen Windows are gorgeous and I would definitely recommend Keller Window and Door to my friends!!

John Keller and his team did an AMAZING job installing our new Anderson windows on our Sun porch! They were professional, friendly & courteous. John is extremely knowledgeable and knew exactly the right windows needed to match our historic neighborhood’s guidelines. John was wonderful to work with. I highly recommend Keller Window and Door!

John and his team were great from start to finish. He provided a no pressure sales quote and was responsive every time I reached out with questions. The installation process was quick, clean, and efficient. Great customer service from start to finish. Can recommend him enough.

Find Us

Proudly Based in O'Fallon, MO

Stop by, call, or book online — we're always nearby when you need us.

Phone

(314) 399-2001

Hours

Monday 8:30 AM - 4:30 PM
Tuesday 8:30 AM - 4:30 PM
Wednesday 8:30 AM - 4:30 PM
Thursday 8:30 AM - 4:30 PM
Friday 8:30 AM - 4:30 PM
Saturday Closed
Sunday Closed