Every bedroom, including a basement bedroom, needs a way out in a fire that a firefighter in full gear can also get in through. Here is what the Minnesota Residential Code asks for.
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Egress window size checker
Open the window all the way and measure the clear opening, not the glass or the frame.
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Clear opening-
Width-
Height-
Sill height-
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Based on Minnesota Residential Code R310 as summarized by the Department of Labor and Industry. Your city's inspector has the final say.
Where an egress window is required
Under section R310 of the 2020 Minnesota Residential Code, which applies statewide:
Every sleeping room needs at least one emergency escape and rescue opening.
A basement needs one too. If the basement has bedrooms, each bedroom needs its own, but the rest of the basement does not.
Habitable attics need one.
Exceptions: a home with a fire sprinkler system, and a basement of 200 square feet or less used only for mechanical equipment.
Minimum sizes
Rule
Minimum
Clear opening, window at or below grade
5 sq ft
Clear opening, above grade
5.7 sq ft
Clear height
24 in
Clear width
20 in
Sill height above the floor
44 in or less
The height and width minimums alone are not enough. 20 x 24 inches is only 3.3 square feet. A 24 inch tall opening needs to be at least 30 inches wide to reach 5 square feet, and a 20 inch wide one at least 36 inches tall.
Clear opening: at least 5 sq ft at or below grade (5.7 above), 24 in tall and 20 in wide.
Sill: no more than 44 in above the floor.
Window: opens from inside without keys or tools. A casement swings fully open.
Well: at least 36 in out from the wall and 36 in wide, 9 sq ft.
Ladder or steps: needed when the well is deeper than 44 in.
Drain: to the foundation drain tile, unless the soil drains well.
Cover (optional): must open from inside without a key, tool or extra force.
The size has to come from opening the window the normal way from inside. It must open without keys, tools or special knowledge. That is why casements are the usual choice: the whole sash swings out. A double-hung or slider opens only halfway, so it must be about twice as big.
Finishing a basement or adding a bedroom
Remodeling or repairing an existing basement does not, by itself, require an egress window.
A new bedroom created in an existing basement does need one.
An addition with bedrooms needs one in each new bedroom, and a new basement needs one unless it connects to a basement that already has one.
Replacing an old basement window
A replacement window can skip the size and sill rules if it is the manufacturer's largest standard size that fits the existing opening, opens the same way (or wider), and the room is not changing use. That keeps a window legal, but it does not make an old small window into egress for a new bedroom.
Window wells
At least 9 square feet, and at least 36 inches out from the wall and 36 inches wide.
Big enough for the window to open all the way.
Deeper than 44 inches: a permanent ladder or steps. A ladder may stick into the well up to 6 inches.
A drain to the foundation drainage, unless the soil drains very well.
Under a deck or porch: a clear path at least 36 inches high to the yard.
Anything over the window or well must still leave the full opening and come off from inside without a key, tool or extra force. The code does not require guards over wells; DLI leaves fall protection to the homeowner, but says a guard must not block escape and to think about snow.
Permits
Cutting a new egress opening is structural work, and Twin Cities cities require a building permit for it. The installer normally pulls the permit and schedules the inspections. Ask before you sign and make sure the permit is in the quote.
Minnesota requires a residential building contractor or remodeler license for contractors who offer more than one kind of work to homeowners. An egress job usually means digging, cutting concrete, framing and setting a window, so ask for the license number and look it up on the Department of Labor and Industry website. Ask for proof of insurance too.
This guide is general information from DLI's summary of the code, not legal advice. Rules change, and your city's inspector has the final say.
Does a basement bedroom need an egress window in Minnesota?
Yes. Under the Minnesota Residential Code, every sleeping room needs an emergency escape and rescue opening, including new bedrooms in an existing basement. The main exception is a home with a fire sprinkler system.
What size does an egress window have to be in Minnesota?
The open window must give at least 5 square feet of clear opening at or below grade (5.7 square feet above it), at least 24 inches tall and 20 inches wide, with the sill no more than 44 inches above the floor.
Is 24 x 20 inches big enough?
No. Those are the minimum height and width, but together they only make about 3.3 square feet. A 24 inch tall opening has to be at least 30 inches wide to reach 5 square feet.
Do I need an egress window to finish my basement?
Not for the remodel itself. The code says an egress opening is not required when an existing basement is altered or repaired. But any new bedroom you create down there needs one.
How big does the window well have to be?
At least 9 square feet, and at least 36 inches out from the wall and 36 inches wide. A well deeper than 44 inches needs a permanent ladder or steps.
Do I need a permit for an egress window?
Yes in the cities we checked. Cutting a new opening in a foundation wall is structural work. The installer normally pulls the permit. See your city below.
What kind of window works best for egress?
Casement windows are the most common because the whole sash swings open. A double-hung or sliding window opens only halfway, so it has to be about twice as tall or wide to give the same opening (This Old House).
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