Young couple pointing at boilers in a shop trying to decide what boiler size they need

What Size Boiler Do I Need? The Ultimate Guide

When you’re looking for a new boiler, one thing you need to think about is what size boiler you need. This isn’t to do with the boiler’s physical dimensions – when people talk about boiler size they’re usually referring to the model’s central heating output. This is measured in kW, and relates to how powerful the boiler is – so how quickly and easily it can supply your home with the hot water it needs. Boiler sizes usually range from 24-42kW.

If you haven’t bought a new boiler before, or haven’t done it for a while, getting to grips with everything you need to look out for can be challenging. Take a look at our boiler size guide to find out why you need to get the right size boiler for your home and how to do it.

Why is it important to get the right size boiler?

When you’re considering new boilers, it’s really important to get one that’s the right size. This is to make sure that your boiler’s powerful enough to meet your heating and hot water needs without wasting energy.

A boiler that isn’t big enough will struggle to heat your home to your desired temperature and supply the volume of hot water that you need. But a boiler that’s too big will produce too much heat, wasting energy and burning more fuel than you need to. Get your boiler size right and you’ll have a comfortable home with the lowest possible energy bill.

What things affect what boiler size you need?

There are several factors that you can use to help you work out what boiler size you need. The number of radiators you have in your home makes a difference – generally the more radiators or rooms you have, the more powerful your boiler needs to be.

The number of bathrooms you have is also worth considering, and the type of bath or shower you have. If you have a deep bath or a power shower (that isn’t electric), these will demand more from your boiler than a smaller bath or low-pressure shower.

It’s also a good idea to think about the number of people in your home, and when they need hot water. If several people in your home need to use hot water at the same time, you’ll need a larger boiler than if you only need to supply one shower at a time. Other things that might make a difference include the type of home you have (detached house, semi-detached house, flat etc.) and the level of insulation it has.

How to find the best boiler for you

Generally, you can use all these things to help you work out which boilers might be suitable for you home. For example, if you have a flat or small house with only one bathroom, the Worcester Bosch Greenstar 28CDi Compact combi boiler could be a great choice for you – this has a central heating output of 24kW. Or if you have a house with 4-5 bedrooms and multiple bathrooms, the Vaillant Eco Tec Plus 630 system boiler could be ideal for your home – this has a larger central heating output of 30kW.

But, it’s important to look at other things, not just boiler size, when you’re trying to decide whether a particular boiler is right for your home. Hot water flow rate, boiler type, efficiency rating and warranty length are all things you need to consider.

Confused? Or don’t have the time to research which boilers are best for your home? Don’t worry, we can help.

Use our simple service to find the ideal boilers for you and your property. Just answer a few questions about your home and we’ll get you information and prices for several boilers that suit your needs. Our service makes it easy to compare models, buy your chosen boiler and arrange installation, all in one simple online process. So, what are you waiting for? Find your new boiler now.

Evy Coe | 17 Oct, 2018


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