Good question. I had a condo that I replaced all windows. I had 6 windows and it was just under $2k. Shop around, I called a couple of companies. You also have the option of putting on things like low-e coatings on the glass which cuts down on the UV rays entering the house. I did that for a window that got alot of afternoon sun. They turned out great. We have since moved into a house and hope we can re-do the windows here soon.