Planning a basement bedroom, home office, or in-law suite? You'll need an egress window — here's exactly what Connecticut requires, what it costs, and what installation actually involves.Get a Free Consultation
What Is an Egress Window and Why It's Required
An egress window is a window large enough for an adult to climb through in an emergency — the legally required emergency exit for any sleeping room below grade. Under IRC Section R310, which Connecticut's building code adopts, every basement sleeping room must have at least one egress window or exterior door meeting minimum dimensions.
This applies whether you're adding a bedroom, a legal rental unit, or a finished room a family member might sleep in — even if it's labeled a "bonus room" on the permit application. If you're planning a broader project, our basement finishing structural guide covers everything else the code will ask of you: ceiling height, load-bearing elements, moisture, and radon.
Connecticut's minimum dimensions
Opening Size
5.7 square feet net clear opening (5.0 sq ft for grade-floor windows).Height & Width
24-inch minimum height, 20-inch minimum width — and you can't hit 5.7 sq ft with both minimums, so one dimension always runs larger.Sill Height
Maximum 44 inches from the finished floor to the bottom of the opening.Deep Wells
Window wells deeper than 44 inches require a permanently attached ladder or steps.Why Egress Matters Beyond Code
Most fatal home fires occur at night when people are sleeping. A basement bedroom without an egress window leaves occupants with only one exit. Beyond safety, a basement room without proper egress cannot legally be listed as a bedroom — in Newington and Southington's market, the difference between a 3-bedroom and 4-bedroom listing is often $30,000 to $60,000 in sale price.
There's an insurance angle too: if someone is injured in a non-compliant room, your homeowner's carrier may dispute coverage. Non-permitted finished spaces are a documented exposure in Connecticut real estate transactions — and they surface at the worst possible moment, during a sale.
What Installation Actually Involves
1. Utility marking & layout
Call Before You Dig marks buried lines; the opening is laid out to clear footings, meters, and interior obstructions.2. Excavation
The well area is dug several feet below the planned sill — rocky Connecticut soil or ledge can slow this step and add cost.3. Cutting the foundation
A concrete saw cuts the opening; in block foundations a steel lintel typically carries the load above the new window.4. Frame & waterproofing
The buck frame is set and sealed — the flashing and sealant work here is what determines whether the window ever leaks.5. Well & drainage
The well (galvanized steel, composite, or timber) is anchored and set on a gravel drainage bed tied to the footing drain where possible.6. Window & finish
A casement window is standard — it clears the opening requirements in the least wall space. Interior framing, insulation, and trim complete the job.What it costs in Central Connecticut
Basic installation with basic interior framing runs $2,500 to $4,500. Full interior finishing brings the range to $3,500 to $6,000. Rocky or ledge conditions common in Connecticut can add $500 to $1,500. Add a clear polycarbonate well cover ($150 to $400) — it keeps snow, rain, and leaves out of the well without blocking the exit, which matters through a Connecticut winter. An ENERGY STAR rated window is worth specifying: below-grade rooms are the coldest in the house, and the efficiency delta is noticeable.