**Introduction:**

When it comes to buying a new radiator one of the most important factors is the heat output and making sure it’s adequate enough for the room. Having a radiator that is too big will end up costing more money to run and having one that is too small will mean the room won’t heat up sufficiently. To help you find the right radiator output for each room we have a handy calculator that will give you the desired BTU/Watt output needed.

**What is BTU?**

After reading the introduction and throughout the article you will notice one term “BTU”. Not everyone knows what it stands for or even means so I will give a brief description as to what it means so that using the BTU Calculator will be easier and the results will make sense.

BTU stands for British thermal unit is the amount of heat required to raise the temperature of 1 pound (0.454 kg) of liquid water by 1 °F (0.56 °C) at a constant pressure of one atmosphere.

**Using the Radiator Size Calculator:**

To determine this, the BTU Calculator will look at range of factors which are; What Type of Room it is, if the house is exposed or sheltered, what window glazing you have and how big the room is. Once all this information has been put it the BTU Calculator will then give a BTU output that is optimal for that room. The BTU Calculator will give two results the lowest and Highest BTU outputs needed to heat the room to a comfortable temperature. This means that there is leeway so anything in-between those two results will be perfectly fine for the room.

Armed with this information you can then find the right radiator for your house.