Converting a vintage cast iron radiator to electric involves understanding its heating capacity. This heating capacity is determined based on the surface area of the radiator measured in square feet. Here’s is how to calculate their capacity once converted to electric.
Determining the Heating Capacity of a Radiator
The heat output of cast iron radiators, historically referred to as Equivalent Direct Radiation (E.D.R.), depends on the water temperature running through it. For conversion purposes, Ecorad calculates a standard water temperature of 175°F, which produces 160 BTU* per square foot of heating surface.
Because electricity measures energy in watts, this BTU figure must be converted. To do this, divide the BTU value by 3.41 which is the conversion factor from BTU to watts.
160 BTU ÷ 3.41 = 46.92 watts per sq.ft.
Example Calculation
Suppose you’re working with a Rococo radiator, 38 inches tall, with 3 columns and 8 sections.
Referring to historical manufacturer data below, this radiator has a heating surface of 40 sq.ft.
To get capacity, multiply the surface area by the wattage per square feet:
Than for this radiator: 40 sq. ft. x 46.92 watts/sq. ft. = 1876.8 watts.
For safety and consistency, Ecorad rounds down to the nearest 250 watts increment. Therefore, this radiator would be fitted with a 1750 watts electric element**.
Simplified Calculations with Precompiled Tables
To simplify this process, Ecorad has compiled these data into easy to use tables. These provide the wattage equivalent for specific radiator models and section counts. For the same example above, in this table the Rococo radiator with 38inch height and 3 columns has an output of 240 watts per section.
As the radiator is 8 sections, calculation is: 8 sections x 240 watts = 1920 watts
For safety and consistency, Ecorad rounds down to the nearest 250 watts increment. Therefore, this radiator would be fitted with a 1750 watts electric element**.
Download our technical specifications booklet for electric converted radiators including these tables.
Ensuring Safety and Efficiency
Vintage radiators vary in manufacturing quality, so Ecorad tests each restored unit to meet UL standards. Advanced safety features include thermal protection with manual reset to ensure safe operations. Each unit is rigorously inspected to maintain both functional and aesthetic integrity while respecting its original craftsmanship.
Why Choose Ecorad for Electric Conversion?
Ecorad’s expertise blends sustainability with respect for heritage design. We optimize energy efficiency while preserving the charm of vintage craftsmanship. Our meticulous work ensure you receive a product that performs reliably and sustainably.
Learn more on ECORAD’s electric conversion process.Â
*Reference: Short Course in Modern Heating by Garnet H. Hopper, published by AGE Publication LTD, 1951.
**Note: these calculations are a guidance, each radiator needs to be tested to meet UL standards and sometimes the capacity need to be decrease.
More information related to this subject:
How to calculate the capacity of radiators for your central system
How to calculate the capacity required for your rooms, just scroll down this page to our calculator.
