It's tempting. You get a high quote from a window company for installing replacement windows and think you can shave costs by doing it yourself. Or you've seen one of these companies in action on a neighbor's house and noted how simple it is to put in a window.
All true. While it takes a certain amount of practice to get it right, window installation is not rocket science. Two problems, though.
The first problem is availability. You can't just go down to your local home improvement store at midnight and buy replacement windows off the rack. You can buy new construction windows off the rack, which you probably don't want.
However, in recent years, window manufacturers have been responsive to some homeowners' desire to install their own replacement windows. Pella's Thermastar line, available only by special order from retailers, allows homeowners to perform their own installation. Vetter Windows offers the same deal. It's interesting to note, though, that you still have to go through local retailers who, presumably, take their own cut off of the sale.
Another problem is exterior cladding. Replacement window companies will wrap your exterior trim with aluminum that matches the color of the windows and provides a tight seal against weather. Specialized tools are needed to form the cladding, and there is a learning curve for working with aluminum, too.
Window companies do this stuff all the time and can usually finish your house in a day or two. And the replacement window industry is so highly competitive, you can easily find a low bid or wrangle a sweet deal.
