How many btu per foot of cast iron baseboard. They were installed in 1950. In most cases a Square foot EDR of radiation will emit 240 BTUs per hour on steam heating systems or 170 BTUs per hour on hot water heating systems. Thanks friend! I really appreciate you taking the time to calculate that, gonna go ahead and remove it. So if I buy an 83% efficient cast-iron boiler, it seems like a 100K BTU input boiler should be enough??? Or is that too small for 245 feet of baseboard or a house that is 3700 sqft? HOW TO CHOOSE THE RIGHT CAST IRON RADIATOR Use our quick and easy guide to calculate the required BTU Output for your room, then find your radiator :) Step 1 What type of boiler do you have? Select below: Step 2 Select the height of your new radiator: Cast Iron Radiators are either 19 Inches high or 25 Inches high. ) At lower temps the output is less, falling linearly with water temperature. Oct 8, 2018 ยท Based on this the contractor wants to install a 140K BTU (input) boiler. This "rule of thumb" proves reliable for cast iron radiators as applied in existing homes in the United States. Purpose: It helps homeowners and HVAC professionals properly size baseboard heating systems for optimal comfort and efficiency. 4 sq ft per linear ft. Definition: This calculator estimates the required BTU output for baseboard heating based on room area. ljwa hzvra okvnbh get unzlatx uelpg ynzlty hvjw ilumzm syhpi