Never hire a window replacement company without doing your homework. You should ask all the questions and clarify your doubts before hiring an agency for replacing your windows. Do your research over the internet and ensure that you hire the best company that helps you enjoy the results for many years together. Collect multiple quotes and make the right decision when you need to hire contractors for commercial historic replacement windows services. Most of the agencies offer free, no obligation quotes and so, you can contact them and get the price estimates to get an idea about the cost in your locality. Good luck.