British Thermal Units (BTUs) are specifically a unit of energy. Contrastingly, Watts (W) represent a measurement of the rate that energy is transferred.
When a conversion occurs from BTUs to Watts, it is actually essentially a conversion from BTUs per hour (BTU/h) into the equivalent amount of Watts.
One Watt equates to 3.41 BTUs per hour, so you divide the total number by 3.41 to convert from BTUs to Watts.
You can use our BTU Calculator to find the ideal heat output you may need to heat your chosen space.
However, when calculating wattage outputs, it is important to take into account the heat lost through transfer from the heating element, to the heating solution, and then from the heating solution to the metal of the radiator itself.
And while our BTU Calculator will give you a conversion based on some clever mathematics, if you are unsure of what this heat loss calculation may be, and want to be as accurate as possible, it may be advisable to consult a plumber or electrician for advice before purchase.