Using a Pressure Washer to Clean Exterior Windows
A pressure washer can be used to clean the outside of windows safely and efficiently, as long as the window cleaning is approached with due care.
Keep the window washing as a separate project from washing walls. Each is likely to require a different water pressure level, a different spray width, a different angle from the surface and probably a different distance from the surface.
If you are using an attachment to wash walls, eg a strong bristled brush, a different one is likely to be a better option for the windows.
To avoid causing damage to the glass or the framework, there are a few main points to note.
1. Keep the pressure low throughout the process. Too high a pressure can break glass and fragment the putty holding it in place, or damage the frame itself.
2. Use a wide angle fan spray nozzle.
3. Keep the nozzle at a safe distance from the glass.
4. Have the water spraying onto the glass at an angle, eg around 40 - 45 degrees. Don't aim directly at the glass.
5. Test out the pressure and the nozzle in a safe place, not on a window, before you begin. Adjust the pressure as needed, until you are sure it is safe for your windows.
6. Use an extension wand rather than a ladder to reach higher windows.