Our home was built in 1913 and has beautiful old wavy glass single-paned windows. I’m so glad we were told about Indows and didn’t have to replace the original windows. We live in Canada but had no difficulty placing the order and were very impressed by how accurately the company met its deadlines, including cross border delivery. The Indows inserts blend in perfectly with our home and the existing window frames. You don’t see them unless you’re actually looking for them. But what we did notice was how much warmer the rooms feel the minute the inserts were installed! I can’t speak to any heating bill savings because they just went in this week, but our home feels much, much cozier. Our contractor who took all the measurements and installed the Indows says: “Excellent instructional videos: clear and informative. Very impressed with the design and the product. Overall, the ease of installation is quite impressive. Working with all the staff at the company was great – everyone was very helpful.” I’m already recommending this company to any of my friends who live in drafty older homes and want to reduce their heating/cooling bills and do some good for the environment.