Window Installation Service serving O'Fallon, MO since 2015

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.

We focus on three product lines because we believe in doing fewer things exceptionally well. We install Andersen Windows, Andersen Patio Doors, and Pro-Via Entry Doors. Each of these products is built to perform for decades, and we install them with the same precision a factory-trained professional would expect. No shortcuts, no guesswork, no overselling products that don't fit your home.

Homeowners across St. Louis and St. Charles counties trust us with their homes, including neighborhoods in O'Fallon, Chesterfield, St. Peters, Wentzville, Wildwood, Ellisville, Creve Coeur, St. Charles, Ladue, Oakville, University City, Ballwin, Town and Country, and Maryland Heights. Whether you're replacing a drafty entry door or upgrading to a new patio door system, we show up prepared, work clean, and leave your home better than we found it.

Our process is straightforward. We scope the job clearly upfront, communicate honestly, and do the work without the high-pressure sales tactics that have become too common in this industry. You get a clear picture of what's happening, why, and what to expect when it's done. That's how we've kept homeowners coming back and referring their neighbors for three decades.

We operate by appointment, Monday through Friday, 8:30 to 4:30. That structure lets us give each project the focused attention it deserves. We're not running crews thin across dozens of jobs at once. When we're at your home, we're focused on your home.

If you're ready to replace windows or doors with products that will hold up and an installation you won't have to second-guess, we'd like to hear from you. Call us at (314) 399-2001 or email jkeller@kellerwindow.com to schedule your appointment.