Radiator Sizing Calculator
Radiator for Room
Calculate BTU output needed for a room
Formula
BTU = Volume x 5 x Exposure Factor x Insulation Factor | Sections = BTU / 250
Frequently Asked Questions
How many BTU per square foot for radiators?
A general guideline is 20-30 BTU per square foot for well-insulated rooms, and up to 40 BTU per square foot for poorly insulated rooms or rooms with many exterior walls.
How do I calculate radiator sections?
Divide the total BTU needed by the output per section (typically 200-300 BTU per section for standard cast iron radiators). The exact output varies by radiator model and water temperature.
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