Your boiler size estimate tool

Don’t guess when it comes to boiler sizes. Use our free size estimate tool to connect you to the perfect boiler for your home's heating requirements.


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What you need to know

Three factors that can determine your boiler size

No. of Bathrooms

The number of shower rooms/ baths in your household will give our engineers an indication of the flow rate your home requires.

No. of Radiators

For your home to be sufficiently heated your boiler needs to be powerful enough to reach all the radiators in your home, therefore, understanding the number of radiators in your home is crucial in determining what size boiler you require. 

No. of Bedrooms

This gives us an idea of the size of your home in a similar way that the number of radiators does, the more bedrooms your home has the higher the output demands on your new boiler.

Did you know we supply Which? approved boilers?

Collection of two white and one black Worcester Bosch Greenstar 8000 Life boilers supplied by Padly
Do you know your boiler types?

What types of boilers should you be considering?

Your old boiler could be a little outdated, or just not efficient enough for powering your home. That’s why you should consider all boiler types and sizes before making your decision. 

Regular (or heat-only)

This type of boiler provides only heat rather than the combination of heat and hot water like a combi boiler does. Any hot water is stored separately in a storage tank and water is fed via a cistern tank to the system. 

We would only recommend a heat-only boiler for your home if you already have one or your property has old pipework. These are the oldest type of residential boilers on the market. 

Combination (combi boilers)

Combi boilers are the most common type of boilers in UK homes, these boilers eliminate the need for a separate water tank as they provide both heating and hot water directly from the mains. These boilers are incredibly efficient in both size and energy usage, without heating a whole tank – you just heat what you use. 

These boilers work on the amount of power you need to heat your home, we can work this out by the number of bathrooms, bedrooms, and radiators you have. If you’re looking to install a new combi boiler with Padly use our boiler calculator to work out the water pressure you need to heat your property. 

System Boiler

System boilers require both a boiler and a cylinder system, these boilers are a modernised version of the regular boilers. These boilers take up much less space than regular boilers as a cistern tank isn’t required. These are, however still a much larger option when compared to the combination boiler.

If your home suffers from love water pressure we wouldn’t recommend you this boiler, system boilers take their water supply directly from the mains and this would negatively impact your flow rate. 

Buy now and pay later with our 0% APR finance options

Collection of two white and one black Worcester Bosch Greenstar 8000 Life boilers supplied by Padly
What size do you need?

Average size boiler for your home

These prices have been worked out based on an average UK home with two working bathrooms. Complete our boiler calculator to receive a tailored price. 

Regular (Heat-only) Boiler

6 Radiators
12 kW
8 Radiators
15 kW
12 Radiators
21 kW
15 Radiators
26 kW
20 Radiators
33 kW

Combination Boiler

1-2 bedrooms, 10 radiators, 1 bathroom
24 kW - 27 kW
2-3 bedrooms, 15 radiators, 1 bathroom
28 kW - 34 kW
4+ bedrooms, 28 radiators, 2 bathrooms
35 kW - 42 kW

System Boiler

1 -3 bedrooms, 1 bathroom
12 kW - 15 kW
3 - 4 bedrooms, 1 - 2 bathrooms
18 kW - 24 kW
4+ bedrooms, 2+ bathrooms
30 kW +
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Get your brand new boiler installed from tomorrow

Collection of two white and one black Worcester Bosch Greenstar 8000 Life boilers supplied by Padly
Lean on the experts at Padly

How to calculate what size boiler your home require

At Padly, we’re here to ensure complicated boiler installations come across as simple. As long as you have to hand how many bathrooms, radiators and bedrooms you have, you can take advantage of our free online quote calculator which will do the hard work for you. 

Padly was founded by a team of homeowners with a focus on simplicity, sustainable living and quality workmanship, which is why all our fixed price boiler installations are carried out by fully vetted, approved gas engineers. We can guarantee your installation will be a transparent, stress free, smooth process with consistent communication throughout. Ready to have your new boiler installed without the faff?