Do I Need a Permit to Replace Windows?
Find out when you need a permit to replace windows. Like-for-like vs. resized openings, energy code requirements, and inspection tips.
Usually no — but yes if you change the size of the opening.
When You Don't Need a Permit
Like-for-like window replacements — where the new window fits the exact same rough opening — typically do not require a building permit. This covers most standard window replacements where you are upgrading the glass, frame material, or energy efficiency without altering the wall structure.
When You Do Need a Permit
A permit is required when you change the size of a window opening (larger or smaller), add a new window where one didn't exist, convert a window to a door or vice versa, or install egress windows for basement bedrooms. These changes involve structural modifications (headers, jack studs) that must be inspected.
Energy Code Requirements
Replacement windows generally must meet the locally adopted energy code — most jurisdictions follow the IECC. Check the NFRC label on any window before purchasing and confirm your local edition's window U-factor requirement. This applies even when no permit is required — it's a code requirement.
Egress Windows
If you're adding a bedroom in a basement, most jurisdictions require an egress window with a minimum 5.7 sq ft net clear opening and a sill no higher than 44 inches above the floor (the IRC standard). Window wells deeper than 44 inches need a permanently attached ladder or steps. This always requires a permit.
Swapping windows in the same opening? No permit needed. Changing the opening size or adding egress windows? Get a permit.
Based on the International Residential Code (IRC) and International Building Code (IBC) model codes. Every jurisdiction adopts a specific edition with its own local amendments — check your city’s permit page for the exact codes in force and their source citations.