How do you calculate BTU? - Grand Designs Magazine

# How do you calculate BTU?

What are British Thermal Units and how do you calculate them? Read this handy guide...

Upgrading your central heating system and wondering what size radiator you’ll need? Then you need to know a little about British Thermal Units (BTUs).

Radiators come in all different shapes and sizes – standard ones, horizontal ones, towel heaters, bench radiators and all manner of designer options.

But they all have one thing in common – their basic function is to transfer the heat of the water within them to the metal of the radiator. They then ‘radiate’ that heat around your room through convection.

## BTU calculator

Put simply, the bigger the radiator, the more heat you will get out of it. But to heat any space effectively and efficiently, the radiator must be able to match its heating output performance to the space. This is measured in BTUs (British Thermal Units).

Working out the heat requirements of your room is relatively easy. It depends on the cubic space you are heating (height x length x width), and then on how well insulated and sheltered your property is. Using a heat output calculator such as the one The Radiator Company’s BTU calculator is the best method.

Upgrading your central heating system and wondering what size radiator you’ll need? Then you need to know a little about British Thermal Units (BTUs).

Radiators come in all different shapes and sizes – standard ones, horizontal ones, towel heaters, bench radiators and all manner of designer options.

But they all have one thing in common – their basic function is to transfer the heat of the water within them to the metal of the radiator. They then ‘radiate’ that heat around your room through convection.

## BTU calculator

Put simply, the bigger the radiator, the more heat you will get out of it. But to heat any space effectively and efficiently, the radiator must be able to match its heating output performance to the space. This is measured in BTUs (British Thermal Units).

Working out the heat requirements of your room is relatively easy. It depends on the cubic space you are heating (height x length x width), and then on how well insulated and sheltered your property is. Using a heat output calculator such as the one The Radiator Company’s BTU calculator is the best method.

## Outputs & Delta T50

It is hugely important to check that the outputs claimed by your retailer can be verified, comply with the current legislation, and that those outputs are published at something called Delta T50. Overstating outputs is sadly a common problem and leads to a long-term cost to the consumer, as well as a huge cost to the environment.

If you are unsure, looking for a supplier that is a member of the Manufacturers Association of Radiators and Convectors (MARC) is a great place to start.

A bench radiator is a great option for a busy hallway. Photo: The Radiator Company

All radiators sold in the UK must be independently certified for output and should have a Declaration of Performance to comply with the law.

## Heat pumps

And if you have a low-temperature heating system – where hot water leaving the heat generator does not exceed 45°C or 35°C – such as a heat pump, do not worry; a quick calculation can be done by your heating engineer. Alternatively, contact The Radiator Company’s technical team, who will ensure you get the right size radiator.

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