What are BTUs? What they mean and why they are important to understand

Heater and thermostat thermal infrared effect
(Image credit: Getty Images)

What are BTUs? is a question you should be asking yourself when you are on the lookout for a new radiator or heated towel rail. They are one of the factors that will tell what sort of heat you can expect from a unit.

Not all radiators and heated towel rails are built the same. So when installing a radiator, even similar sized radiators can have different BTU ratings. When choosing a new radiator or similar, checking the BTU will help you choose the most efficient and effective radiator for the space you are looking to heat

Here we define BTUs, what they mean, why they are important to know and answer other common questions 

What are BTUs?

Headshot of expert Mark McShane on purple background
Mark McShane

Mark is a fully qualified plumber, gas engineer and electrician with a passion for helping people install renewable energy solutions. He own the Skills Training Group, who provide training and apprenticeships for the heating, plumbing, and electrical industries. 

Steve Jenkins

Steve Jenkins is a freelance content creator with over two decades of experience working in digital and print and was previously the DIY content editor for Homebuilding & Renovating. 

He is a keen DIYer with over 20 years of experience in transforming and renovating the many homes he has lived in. He specialises in painting and decorating, but has a wide range of skills gleaned from working in the building trade for around 10 years and spending time at night school learning how to plaster and plumb.

He has fitted kitchens, tiled bathrooms and kitchens, laid many floors, built partition walls, plastered walls, plumbed in bathrooms, worked on loft conversions and much more. And when he's not sure how to tackle a DIY project he has a wide network of friends – including plumbers, gas engineers, tilers, carpenters, painters and decorators, electricians and builders – in the trade to call upon.