Karyn and I recently celebrated our wedding anniversary by taking a two-day bicycle trip that included a stay in a Vermont inn. I noticed that our bed-and-breakfast bedroom had a single window, presumably sized to be an egress window. There was a window-mounted air conditioner in the window, which got me thinking: is it legal to install a window-mounted air conditioner in an egress window, if the window is the only window in the bedroom?
After conducting some research, I know the answer to the question. Like almost all code questions, the answer is, “It depends.” Whether or not this type of air-conditioner installation is legal depends almost entirely on the discretion of your local building inspector.
Common problems with egress windows
There are several ways that builders and remodelers get in trouble for violations of egress-window requirements—technically known as “emergency escape and rescue opening” requirements for bedrooms. Typical violations include:
- Basement bedrooms that lack an egress window
- Bedroom windows that are too small
- Bedroom windows with stools that are too high off the floor
Disputes over window-mounted air conditioners are less common, but they certainly occur.
What does the code say?
Code requirements for emergency escape and rescue openings can be found in Section R310 of the International Residential Code.
To meet emergency egress requirements, a window:
- Needs to be operable (not fixed).
- When opened, needs to have an opening that begins no higher than 44 in. above the flooring.
- Needs to have an opening that is at least 20 in. wide.
- Needs to have an opening that is at least 24 in. high.
- Needs to have an opening that measures at least 5.7 sq. ft. (unless the window is located on the ground floor, in which case the minimum opening area is 5 sq. ft.).
Note that a window that barely meets…