Window replacement costs in Chattanooga

The Chattanooga metro crosses a state line, and so do the lead-paint rules for window work. EPA has authorized Georgia to run its own renovation, repair and painting program. Tennessee isn't on that list. So for a house in the Georgia counties of the metro, Georgia sets the training and certification your contractor needs. On the Tennessee side, it's EPA.

Either way, those rules apply to homes built before 1978, and that's a lot of houses here. Roughly 42 percent of the area's houses trace back to before 1980, and about a fifth to before 1960.

On the Tennessee side, EPA's rule is blunt about windows. It lets small jobs that disturb only a little painted surface count as minor repair, but window replacement is carved out of that exemption. EPA says replacing a window of any size, even one under six square feet, is a renovation. One small bathroom window on a 1950s house is lead-safe work.

Rain is the other local factor. The Chattanooga airport averages about 55 inches of precipitation a year. On older wood windows, that water finds the bottom rail and the sill first. When a replacement goes in, the flashing and the slope of the sill decide whether the next 55 inches run off or soak in.