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Heat Loss Calculator

It's your radiator to warm up your space so you get to choose how it looks.  There are a few simple steps to follow to help you build the perfect radiator.

  1. Work out what size you need to heat your room or fill your space.

  2. Request a free design sheet to work out what you need

  3. Browse our range of Cast iron, Steel & Aluminium Radiators to see what is on offer

Choosing which radiator that is best for you is not as complicated as it may seem.  You need to make sure that your radiators will provide enough heat to properly heat your room and this is all about knowing the BTU’s, Watts and even joules. 

First a quick physics lesson. 

BTU stands for British Thermal Unit and that’s the standard way to work out how much heat output is needed to heat a space or room.  Some like to use the SI derived unit for power instead the ‘watt’.  1 watt equals 3.41 BTU per hour.  1 BTU equals 1055 joules and that’s the energy needed to heat 1lb of water by 1°F.  There goes the bell, physics lesson over!


Now the simple version, work out the BTU output of your room using our simple calculator.  It takes into account what room it is for.  For example a Living Room would be warmer than a Bedroom.  It also factors in heat loss from your windows.  All you need to know is the room dimensions and what radiator you like and it will tell you how many sections you require.  You don’t want too high an output or you will be able to grow tomatoes, too low an output and your heating will be on all the time.  The standard temperature of water from your boiler is 60° C so that’s what we use for our calculator.  We do show the BTU output at 50° C on the technical information sheet. All cast iron radiators are built here in the UK by section.  They are assembled to your exact specification, pressure tested and then painted before shipping. 


If you get stuck just send us an email or give us a call and we will help you work it out.

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