What size of a garage will the GG030A1NSA11 unit heat?

Hello, thank you for reaching out. The Sterling GG030A1NSA11 is best suited for a 1 to 1.5-car garage, typically heating spaces of 250 to 400 sq. ft. under normal insulation and climate conditions. If you have additional questions, please feel free to reach out over the phone to our Customer Service line at 1-888-901-5460. Have a great rest of your day.