The cost to install a window in an existing wall will differ from project to project. A price range that you can expect for the combination of the siding, framing, and finishing work is between $1,000 and $5,000 per window. If that’s within your budget, get in touch with a local contractor. You can schedule a free estimate with our team to find out the cost to add a window if you need to replace five or more windows on your home.