Calculate the BTU output needed for radiators in each room of your home.
BTU Required
5,691
1,667 Watts
Room Volume
33.6 m³
BTU Output
5,691
Watts
1,667 W
How to use this Calculator Site tool
Enter your room's dimensions, the number of windows and external walls, and the quality of insulation. Our calculator will instantly provide the required BTU and Wattage to heat the space effectively, ensuring you choose the right radiator.
Selecting the correct radiator size is crucial for both comfort and energy efficiency. An undersized radiator will struggle to heat your room adequately, leaving it cold during winter. Conversely, an oversized radiator will waste energy and potentially lead to higher heating bills. Our calculator considers key factors like room volume, insulation quality, window area, and the number of external walls to provide an accurate BTU (British Thermal Unit) requirement.
15-20%
Heat loss through windows
~35%
Heat loss through walls
10°C
Drop if uninsulated
Factor in All Variables
For the most accurate BTU calculation, be sure to count all windows, including small ones, and correctly identify external walls (walls that border the outside). Double-glazed windows and good insulation can significantly reduce your heating needs.
Understanding your home's energy usage is the first step towards reducing your bills. This Radiator Size Calculator is one of many free tools provided by Calculator Site to help you make informed decisions. You may also find our Gas Heating BTU Calculator useful for related calculations, or the Energy Bill Calculator for a broader view of your household expenses.
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