When the cold weather sets in that will be the test! I found the process relatively easy after a few false starts. I used the videos to help me. It was a little difficult for me to use the laser measuring tool, because I already had blinds installed and my windows are tall - I am short - and I didn't know how to take them down and reinstall, and I really didn't want to do that. So there was a bit of guess work involved. I held my breath when the inserts arrived. It was a really tight fit, but I got them in. The hard part was getting them up underneath the blinds and shoving them into place, but I did it. They fit snuggly. Now I have to figure out how to better insulate my front door and I should be comfortable in my downstairs this winter. Builders grade is almost as bad as Historic Preservation sometimes. Wish me luck.