Click in the boxes above then backspace out the current details, then enter your new details and click the "Calc BTU Button".

You will be presented with a clickable list of vent free heaters which can achieve your aim.  You will have a choice of radiant (red flame) or blue flame heaters.

If you need to know more about the difference between radiant or blue flame heaters. Click here to read our FAQs: Question 1

This calculator aims to accomplish your heating job in ONE HOUR or less. The resulting BTU range is estimated and is used as a point of reference.

Depending on the size of your room or the temperature you're aiming for, this can sometimes result in a much larger heater than you really wanted.

If you can run the heater for longer and wait for the room to warm up or simply turn on the heater earlier you can use a much smaller heater.

For example:
You can use a 1500 Watt heater in a 12x12 room with 8 foot ceilings.
And use the same heater in a 15x15 room with 10 foot ceilings.
The 12x12 room will just reach the perfect temperature more quickly.

To make the calculator report smaller heater sizes for you simply reduce your desired temperature increase.

The resulting BTU range is estimated and is used as a point of reference.

For detailed information on sizing a bathroom or bedroom according to National Building codes refer to FAQs: Question 5