How it works
One or more large glass panels run horizontally on a track set into the sill, the jambs and the header. Usually one panel slides and one is fixed, so the clear opening is about half the door. Nothing swings, which means the floor on either side stays usable right up to the glass.
Where it fits an Inland Empire home
This is the standard way to connect a kitchen or a family room to a patio, which describes a lot of the houses we work in. It is the right call whenever a swinging door would land in furniture or across a walkway, because a sliding panel never needs an arc to open.
What to watch for
The track is the maintenance item. Dust and yard sand work into it, and a slider that drags is usually telling you it needs cleaning rather than replacing. That takes a few minutes, a few times a year.
Airtightness comes from the weatherstrip compressing where the sliding panel meets the fixed panel and the frame, and that seal wears the same way a slider window’s does. Hardware quality matters more than the glass for keeping conditioned air in the house.
On a retrofit, sill pan flashing under the threshold is the detail that decides whether you have a leak two winters from now. A door sill takes far more direct water than a window sill does, and that flashing goes in before the door does, or it does not go in at all.
A sliding glass door counts as a large glazed opening under the energy code, so it carries the same Climate Zone 10 numbers as a window, a U-factor at or below 0.30 and a solar heat gain coefficient at or below 0.23 on most jobs. Facing west, that is as much glass as several windows put together, so a patio cover or a deep overhang does more for the room than any glass package can on its own.