Room size
Climate and insulation
Moderate covers most US heating zones with winter design temperatures around 15-25°F.
Room characteristics
Living spaces are sized for 70°F. Bathrooms are sized warmer (72-75°F). Bedrooms can be slightly cooler.
Heating system
Standard hot water boilers run around 180°F. Modern condensing boilers run cooler (130-160°F) which derates radiator output significantly.
Radiator BTU needed
Heating load
0
BTU/hr to heat room
Radiator output needed
0
BTU/hr rated capacity
In watts
0 W
European spec format
In EDR (steam)
0
sq ft equivalent radiation
Radiator output ratings assume a specific water temperature – usually 180°F for hot water systems. If your boiler runs cooler (condensing systems, low-temp setups), the radiator will deliver less heat than its rated BTU. Always size for the system you have. For steam, 1 sq ft EDR equals 240 BTU/hr.