Find Window Replacement Services in O Fallon, MO

"I ordered new windows for my entire house. This was done extremely professionally and I couldn't be happier with the results. Everything was measured and installed perfectly. It's incredible how much of a difference this made. You will not be disappointed!!!"

"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."

"John Keller did a great job on our windows after the March storm. He was patient with all of my questions about styles and colors."

"In October 2024, we got Andersen replacement windows through Keller Window & Door for our entire house (13 windows) along with one custom window and 3 new basement windows. John provided OUTSTANDING service throughout the entire process start to finish. And John and his team installed the high quality windows to perfection. We love how they look! Even before our recent major project, we had John fix a couple issues on our French doors which were installed by someone else. He treated those minor issues with the same priority and professionalism as our house-wide project. It is rare these days to have such exceptional product quality and customer service from a contractor. But you can count on that with John and his team at Keller Window & Door for any project. We highly recommend them and promise you will be fully satisfied with the service and finished product!"

"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!"

"I had an excellent experience hiring John and his team to replace our patio door with a sliding glass door and replace all of our windows in the basement with newer more energy efficient windows. The pricing is much better compared to other bids and the work was done very well. I could tell that the crew had a lot of experience and knew what they were doing and it showed in the quality and speed of the work."

"We had our old patio door replaced by Keller Window & Door last month (Oct. ‘22), and Wow! What a difference! We absolutely love it! They did a fantastic job! Highly recommend!"

"I ordered new windows for my entire house. This was done extremely professionally and I couldn't be happier with the results. Everything was measured and installed perfectly. It's incredible how much of a difference this made. You will not be disappointed!!!"

"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!!"