Does a sunroom count as square footage?
Published August 27, 2026
Only if it is finished and heated like the rest of the house. A four-season sunroom on a permanent foundation with insulated walls, house-standard heating and cooling, finished floor and ceiling, and a 7-foot ceiling counts as gross living area under ANSI Z765. A three-season room or enclosed porch that is unheated, uninsulated, or finished to a lower standard does not; it is reported as a porch.
Three-season vs. four-season
| Feature | Three-season (does not count) | Four-season (counts) |
|---|---|---|
| Heating and cooling | None, or a space heater | Ducted or permanent, same as the house |
| Walls and glass | Single-pane, screens, aluminum panels | Insulated walls, insulated glass |
| Floor | Deck boards or slab | Finished floor at house level |
| Foundation | Deck piers | Permanent foundation |
Manufactured sunroom kits
Most aluminum-and-glass sunroom kits are three-season rooms even when the owner adds a heater. Appraisers judge by construction and finish level, not by the thermostat. A space heater does not get it there either; heat alone is not enough.