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.
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:
Disputes over window-mounted air conditioners are less common, but they certainly occur.
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:
Note that a window that barely meets the minimum width and height requirements is not large enough to meet the minimum area requirement.
The code is silent on whether it is legal to install a window-mounted air conditioner in an egress window. However, one section of the code (Section R310.4) seems relevant. That section states, “Bars, grilles, covers, screens, or similar devices are permitted to be placed over emergency escape and rescue openings … provided that the minimum net clear opening size complies with Sections R310.1.1 to R310.2.3, and such devices shall be releasable or removable from the inside without the use of a key, tool, special knowledge or force greater than that required for…