There are plenty of reasons to replace your old windows. Today's options are more energy-efficient, saving you money on your heating and cooling bills. They also come in a array of convenient options that make open, closing, and cleaning much easier. And good windows add value to your home. Mid-range wood windows return 79.3% on an average cost of $10,926 and mid-range vinyl replacements return 78.7% on an average cost of $9,978.