When selecting cast iron radiators, it’s important to consider both the heat output of the radiator and the size and purpose of the room where it will be installed. Each of our cast iron radiator models has a different heat output rating, which you’ll find listed on the individual product pages. These ratings are measured in BTUs.

Use the calculator below to estimate the BTU requirement for the room where you plan to install your radiator. This will help ensure you choose the right size radiator for comfort and efficiency.

Please enter the room details and dimensions in feet or meters. Your BTU requirement will appear below.

First, enter your room details

Second, enter your room dimensions

Enter in either feet or meters—values will sync automatically.

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Your BTU requirement

This is an estimated calculation based on the information above.

Standard Gas Boiler (BTU ΔT=50)
Heat Pump (BTU ΔT=30)