Comparison Guides
Sunroom vs Three-Season Room vs Screen Room: What Is the Difference?
June 18, 2026
These terms get used interchangeably. They should not be. A screen room, a three-season room, and a four-season sunroom are three different products with three different price tags and three different jobs. Here is the real difference, mapped to the Sunspace models we install.
Side by side
| Feature | Screen Room | Three-Season Room | Insulated 4-Season Sunroom |
|---|---|---|---|
| Sunspace model | Model 100 | Model 200 WeatherMaster vinyl or Model 300 glass | Model 400 |
| Walls and windows | Screens | Vinyl windows that open up to 75 percent, or single-glazed glass | Foam-insulated walls with Low-E argon glass |
| Season of use | Spring through fall, open air | Spring through fall | Year-round |
| Insulation | None | Minimal | Thermal walls, thermal breaks, Low-E argon |
| Heat and cool | No | Not designed for it | Yes, like any room in your home |
| Bugs and weather | Bugs out, open to the breeze | Bugs, rain, and UV out when closed | Full weather protection |
| Relative cost | Most affordable | Mid | Highest |
| Maryland winter | Not for winter | Not for deep winter | Comfortable all winter |
Screen room (Model 100)
An all-screen room is the most affordable way to enjoy a deck or patio without bugs. You get full airflow and shade. You do not get rain protection or winter use.
Three-season room (Model 200 or 300)
A three-season room steps up to real windows. The Model 200 WeatherMaster uses vinyl panels that slide open up to 75 percent for airflow. The Model 300 uses single-glazed glass for a cleaner look. Both keep out bugs, rain, and UV when closed. Neither is designed to be heated through a Maryland winter.
Insulated four-season sunroom (Model 400)
A Model 400 sunroom is built like an addition. Foam-insulated walls, thermal breaks, and Low-E argon glass mean you can heat and cool it like any other room in the house. Use it every day of the year.
Which is right for you
If your budget is tight and you only want bug-free outdoor time, pick a screen room. If you want to use the space spring through fall without dealing with weather, pick a three-season room. If you want a true year-round room you can sit in on a January morning with coffee, pick an insulated sunroom. See all four models on our sunrooms page.
Still not sure which model fits?
Tell us how you want to use the room. We will tell you which Sunspace model gets you there for the lowest reasonable cost.
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