The fixed window wins on tightness, energy, size, sightline and price, and does not open. Which openings need to, what the code requires, and how we lay out a wall.
A fixed window is the best window there is at everything except being a window: it is the tightest, the most thermally efficient, the largest, the slimmest and the cheapest, and it does not open. So the question is never fixed or operable for a whole building; it is which openings need to open. The code answers part of it — every bedroom needs an operable egress window, and most codes want natural ventilation in habitable rooms — and comfort answers the rest. The pattern that works: fixed where the view is, operable beside it where the air comes in.
| Feature | Fixed (picture) window | Operable window |
|---|---|---|
| Opens | No | Yes: tilt-turn, casement, hung, sliding, awning |
| Air and water tightness | Best: no sash, no seals to wear | Good on compression types; weaker on sliding types |
| Thermal performance | Best for the same glass: more glass, less frame | Slightly lower: sash adds frame area |
| Glass size | Largest; limited by glass, not hardware | Limited by sash weight and hardware |
| Sightline | Slimmest | Frame plus sash; wider |
| Ventilation | None | Yes |
| Egress (bedrooms) | Not allowed as the sole window | Required in every bedroom: a clear opening of code size |
| Cleaning | From outside, or from an adjacent operable unit | From inside on tilt-turn and tilt-in types |
| Cost | Lowest | Higher: hardware |
| Where it suits | Views, stairwells, high lites, the middle of a bank of windows | Every room that is lived in |
No sash means no second frame around the glass, so a fixed unit has more glass and less aluminum for the same opening — better U-factor, slimmer sightline, less to look at. No seals or hardware means nothing wears and nothing leaks; a fixed lite is as tight in year twenty as on day one. And no weight limit on hardware means the glass can be as large as glass comes: the tall fixed lites on the Ocean Parkway house and the curtain-wall infills at The Anable could not be operable at that size. It is also the cheapest unit in any system.
Egress, first: the building code requires every sleeping room to have an operable window with a clear opening large enough to climb through, and a fixed window does not count. Ventilation: most codes require natural ventilation in habitable rooms, and beyond the code, a room with no opening window is a room with stale air and a condensation problem. Cleaning: a fixed lite above the second floor cleans from outside, or from the operable unit next to it. And the human thing: people want to open a window. The operable types and how they differ are compared at casement vs double-hung vs tilt-and-turn; for a trickle of secure air without swinging a sash, see trickle vents vs tilt-and-turn.
On a wall with a view: a large fixed lite in the middle, an operable unit on one or both sides, sized so the operable meets egress if the room is a bedroom. On a stairwell or a double-height space: fixed, cleaned from outside or a lift. On a rental program: operable everywhere, because tenants open windows and the code requires it, in a tilt-turn with key handles for control. On a facade: fixed curtain-wall infills with operable inserts where the plan needs them, which is how The Anable was built. The mix is drawn per room, not per building.
No. Every sleeping room needs an operable egress window with a clear opening of code size. Fixed lites can be added beside it.
Yes, for the same glass: no sash means less frame and no seals to leak. The difference is modest with a good operable unit and large with a poor one.
As big as the glass and the frame can carry; operable units are limited by sash weight and hardware. Oversize fixed lites are common on facades and custom houses.
From outside, from a lift, or from an adjacent tilt-turn unit that swings in. Plan the operable unit next to the fixed one for that reason.
Fixed, in every system: no hardware, no sash.
Fixed Windows Operable Windows Operable Types Compared Trickle Vent vs Tilt-and-Turn All Comparisons
About this page. Written by Alex GC Inc. d/b/a Alex Glass Construction and reviewed before publication by Aleksandr Chernovolenko, Managing Partner, with our design and estimating lead and a field foreman. Our foremen hold the NYC DOB Site Safety Training supervisor card and our crews the 40-hour worker card; we are certified to fabricate, install and service Alutech and Everest aluminum systems. Facts are drawn from our own projects, manufacturer test data and the applicable codes; where we are giving an opinion, we say so. Last reviewed September 2026. Credentials
Send the elevation or a photo and tell us which rooms are bedrooms. We will draw the fixed-and-operable mix and quote it.
