Replacing an Old Basement Window: Same Size or Egress Size?

Fixr puts basement window replacement at $500–$1,000, with a $750 national average; adding a new well with the window raises that to $2,500–$7,000. Under 2018 IRC R310.2.5, a replacement can skip the egress size and sill rules if it is the largest standard size that fits and opens at least as wide as the old one.

Same opening, or a bigger one?

If the room is storage, a mechanical room or a family room, a straight replacement in the existing opening is usually enough. If it is a bedroom, or will become one, the window has to meet the full escape-opening rules, and that normally means a taller or wider opening and a proper well. Omaha's amendments treat any room over 70 sq ft with built-in closet space as a sleeping room, so a finished room with a closet should be measured against the bedroom rules.

What the replacement exemption allows

Section R310.2.5 of the 2018 IRC exempts a replacement window from the 5.7 sq ft opening rule and the 44 in sill limit when all three of these hold:

• it is the manufacturer's largest standard size that fits the existing frame or rough opening;
• it is the same operating style, or a style that opens at least as much as the old window;
• it is not part of a change of occupancy.

That keeps a like-for-like swap legal. It does not turn an undersized window into a qualifying exit for a new bedroom.

Which window types suit a basement window replacement?

Fixr's 2023 basement window guide lists unit prices, before labor, of $100–$250 for a prefab hopper, $100–$300 for glass block, $150–$700 for a slider and $200–$500 for a casement. Labor runs $150–$700 per window. Hoppers and glass block suit light and ventilation. A slider or casement may get close to egress size if the opening allows it.

Older Omaha basements

Nearly 18% of Omaha's homes were built in 1939 or earlier, and the median home dates from 1973 (U.S. Census). Houses of that age often still have original steel or wood basement sash, sometimes painted or rusted shut. A replacement is a good moment to decide whether that room will ever be a bedroom; cutting the opening once costs less than replacing a window now and cutting it larger later. Compare both routes with the egress window price guide for Omaha.