Expert Window Installation Service Serving O'Fallon

Premium Andersen windows and ProVia doors installed with factory-level precision across the St. Louis area.

5.0 11+ Google reviews
What We Do

Window Installation Service in O'Fallon, MO

From quick repairs to full projects, we help you choose the right window installation service services without pressure or guesswork.

Not sure what you need? We will assess your project at no cost.

Call (314) 399-2001
Professional installation crew with tools and materials ready for window and door replacement work.

Since 2015

Serving locally
St. Charles County

Our Story

Thirty years of installs,
done with precision

Keller Window & Door LLC was built on something most window and door companies can't claim: real, inside knowledge of the products we install. Our owner spent years working directly with Andersen before starting this business, which means the expertise here goes well beyond reading a spec sheet. That background shapes how we approach every job, from the first measurement to the final walkthrough.

Over 30 years of installations, we've seen what separates a job done right from one that causes headaches three winters later. Andersen products are only as good as the installation behind them. That's why we pursued and earned Andersen Certified Contractor status, and then went further to achieve Andersen Elite Certified distinction. These aren't participation awards. They reflect verified standards, consistent quality, and a track record homeowners can rely on.

Our Full Story
How We Work

How We Work

We keep our process simple and transparent. From your first call through installation and beyond, you know what to expect.

Schedule Your Consultation

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

In-Home Assessment

We visit your home to measure openings, review your current doors and windows, and discuss your goals. You'll learn exactly what we recommend and why.

Professional Installation

Our team installs your Andersen or Pro-Via products with precision and clean workmanship. We handle the job start to finish with no shortcuts.

Final Walkthrough & Support

We review the completed work with you, answer any questions, and ensure everything operates smoothly. You have our contact info for any follow-up needs.

We handle all measurements, installation, and cleanup. No surprises, no guesswork—just quality work done right.

Where We Work

Window Installation Service Services Across
O'Fallon

Based in O'Fallon — serving every corner of O'Fallon.

Primary Service Area

O'Fallon, MO

O'Fallon is a fast-growing community in St. Charles County with a mix of newer residential developments and established neighborhoods. The city spans both sides of I-70 and includes areas like Ameristar and the downtown corridor. We serve all of O'Fallon's residential and commercial properties.

Cities & Communities We Serve:

O'FallonWentzvilleSt. PetersSt. Charles
O'Fallon, MO Services

Chesterfield, MO

St. Peters, MO

Wentzville, MO

Wildwood, MO

Ellisville, MO

Creve Coeur, MO

St. Charles, MO
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!

Pat Raines Google review · August 2026

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

Audrey Wilson Google review · July 2026

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!!

Eve Cascella Google review · June 2025

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!

Ed O'Brien Google review · September 2024

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.

Matt Kuelker Google review · June 2025

Ready to become our next happy client?

(314) 399-2001
FAQ

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

Answers to the questions homeowners ask most before hiring a contractor. Not seeing yours? Call us. We are straightforward about our process, pricing, and expectations.

We primarily serve O'Fallon, MO, Chesterfield, MO, St. Peters, MO, Wentzville, MO, Wildwood, MO, Ellisville, MO, Creve Coeur, MO, St. Charles, MO. If you are outside these areas, call us. We take select projects beyond our standard service radius for the right scope.

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.

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

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

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
Find Us

Proudly Based in O'Fallon, MO

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

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
Get Started Today

Get Your Free Window & Door Estimate

Keller Window & Door LLC serves O'Fallon, MO and the surrounding area with professional Window Installation Service services. Free estimates, clear options, no pressure.

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
Call (314) 399-2001

Mon–Fri 8:30 AM - 4:30 PM · Sat Closed · Responses within 2 hrs

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