Short answer: add up the square footage you want to heat, adjust for insulation, and match it to a model. Or let our size calculator do it for you.
How to figure it
- Add up the square footage of the main floor.
- Add half the square footage of the basement or upstairs.
- Poorly insulated? You may need up to twice as much boiler.
- Keeping a shop at 50° instead of 70° takes a lot less boiler.
- Up here in Wisconsin and Minnesota, size up rather than down.
What each model heats
- C150: up to 3,000 sq ft
- G4000: up to 4,000 sq ft
- C250: up to 5,000 sq ft
- G7000: about 7,000 sq ft
- C375: up to 7,500 sq ft
- G10000 and C500: up to 10,000 sq ft
- C800: up to 20,000 sq ft (barns, shops, greenhouses)
- B500 and B1000: large commercial buildings, 20,000 to 40,000+ sq ft
Full specs are on each series page. Not sure? Ask us and we'll help you size it.