Increasing the market value of your house is another advantage of doing a home window replacement project. Though you will be spending some serious cash in having your windows replaced by the professionals, you will get back what you have invested in the form of your home value. Based on realtors and real estate appraisers, you add between 80% and 85% to the value of your home with an upgrade. For instance, if a home window replacement project costs you $8,000, your home value will increase to about $6,400 in the market. If you stay in your house for the coming year, you would be getting back the 20% difference via appreciation.