What Size Boiler Do I Need for My UK Household?

One of the most common questions homeowners ask themselves when it comes to central heating is "what size boiler do I need?". Finding the answer to this question will help you keep your central heating costs low, both in terms of installation and future energy bills.

In this article, we'll guide you through what exactly is meant by "boiler size", what the boiler sizing rule of thumb is, and why it's beneficial to get the right size.

Installing the wrong size of boiler can be a costly mistake. New boiler prices can be high, so you won't want to risk paying even more than you have to. It's always a good idea to seek advice from a professional in order to make sure you're getting the correct type and size of boiler for your home. But how do you find a heating engineer available in your area and for a fair price?

Searching for heating engineers on your own can be stressful and take up several hours of your free time. Thankfully, it doesn't have to be this way. Household Quotes can help you find multiple heating engineers quickly, so that you can easily compare their prices and spend your free time doing something more enjoyable instead.

Click the button below to receive up to 3 quotes from qualified heating engineers available in your area and choose the best deal. Our service is completely free and you don't have to select any of the quotes you receive.

When you hear installers talking about boiler sizes, they're referring to the output rating of the boiler and not its physical dimensions. This output rating is measured in kilowatts (kW). All boilers will state a central heating output rating, and if you have a combi boiler then you can also expect to see a hot water output rating mentioned in the specs.

You can think of boiler sizes in the same way as battery sizes, which are also classed in terms of their power rather than their dimensions (e.g. AA, AAA, etc.). So for boilers, it's very similar: you'll see boilers come in different sizes such as 24kW, 36kW, etc.

You're probably wondering now "what kW boiler do I need for my home?". This will depend on multiple factors, such as the size of your home, the amount of radiators and bathrooms you have, your home's insulation, and your personal needs when it comes to heating and hot water. Further below, we'll go into more detail about how some of these factors influence what size boiler you'll need.

Figuring out how to size a boiler can feel confusing and you may also be tempted to put more weight on factors such as price when choosing your boiler (because who doesn't want to get the cheapest heating system possible?). However, working out how big of a boiler you need correctly the first time can end up saving you money down the line.

Firstly, if you choose a boiler with too small a kW size there is the risk that it won't meet your household's heating and hot water needs. Waking up shivering in the morning and then getting into a cold shower probably isn't how you want to start your day!

You might also be thinking about playing it safe and just getting the biggest kW size possible, however, this also comes with drawbacks. The most obvious drawback to this is the upfront cost, as boilers with higher kW outputs are typically more expensive. Therefore, you don't want to overpay for something you don't need.

Another drawback to getting a boiler that has a bigger kW output rating than you need is that an oversized boiler will 'cycle' on and off excessively. This means that your boiler will heat up quickly but then will also have to turn off quickly in order to avoid overheating. This leads to your boiler using more fuel than necessary, which in turn will increase your energy bills, whether it's gas, LPG, or oil fired boiler prices.

Excessive cycling also puts more stress on your boiler's components, which could lead to more maintenance costs over time. Therefore, a little bit of research and consulting a professional can save you a lot of money in both the short and long term.

However, if you only consult one professional, there's the risk that they'll overcharge you. This is why it's so essential to compare quotes from multiple qualified installers. But where do you find these experts and how do you know if they're qualified? This is where Household Quotes comes in.

We have a vetted network of qualified and trustworthy boiler installers across the UK. So just by filling in a short form and specifying your needs, we can quickly connect you with up to 3 boiler installers. You'll receive a quote from each one, meaning that you can easily compare their prices and choose the best one.

What's more, our service is completely free and non-binding. Click the button below to get your free quotes now.

Below, we've provided a rough guide for sizing a boiler based on the number of bedrooms, radiators, and bathrooms you have in your home. This will help to give you an idea of how big a boiler you need for your home.

As you can see in the table above, how many kW you need for your boiler can vary a lot and there is overlap. This is mostly because the boiler size you need largely depends on the type of boiler you get for your home. In the next section, we will break this down further.

At the end of the day, the best way to be certain about what size of boiler you need is to seek advice from a professional. Thanks to their knowledge and experience, they'll be able to consider all relevant factors and advise you of an appropriate kW size for your personal situation.

However, finding a qualified heating engineer who's available in your area quickly can be a challenge. Researching and contacting heating engineers one by one can eat into hours of your free time, and after all that it can be frustrating to find out they're not available soon.

Thankfully, Household Quotes has a solution. By filling in our short form, we can quickly and easily connect you with trustworthy and vetted heating engineers from our network. This way you can connect with up to 3 available professionals without the extra stress. Click the button below to get your free, non-binding quotes now.

The boiler type influences what size boiler you need for your house. This is due to the difference in how different types of boilers operate. Combi boilers generally have higher kW outputs in order to heat water on demand. System and conventional boilers, on the other hand, generally have lower output sizes, as they operate by slowly boiling and storing hot water for future use. Conventional boilers are also referred to as regular or heat-only boilers.

Therefore, you will need to take boiler type into consideration when choosing the appropriate power output size.

So to answer your questions of "what size combi boiler do I need?" or "what size system boiler do I need?", we've provided two helpful tables below to give you a more accurate idea of what size boiler you need for your house.

If you're not sure which type of boiler you want for your home yet, you can read our articles on system boiler prices and combi boiler prices, to compare these types of boilers on costs (as well as other factors) to get a better idea of what is a good fit for your home.

You might also be wondering "what size oil boiler do I need?" or "what size gas boiler do I need?". Does the fuel type affect the kW size you need for your boiler? The fuel type you opt for will largely depend on whether or not you're connected to the gas grid and what the current fuel prices are more than anything else.

Some fuel types are typically more efficient than others, which you will see as an efficiency rating in a boiler's specs. Some people recommend to get a slightly higher kW output for a lower efficiency rating, but overall there is not too big a difference in efficiency ratings between boilers. A qualified heating engineer will always be able to advise you on what's best for your home.

A boiler might not be the most exciting of purchases, however, it is something that affects your daily comfort and potentially safety, so it's worthwhile making sure you get the best fit for your home.

Furthermore, boilers can be expensive. So as well as making sure you get a boiler that's suitable for your home and needs, it's also crucial to compare prices to make sure you're getting the best value for your money. We've written articles on some of the most popular manufacturers of boilers so that you can get a better idea of their benefits and costs:

However, the brand and model are not the only factors that affect upfront costs, you'll also need to consider the installation costs. In order to find the best installation costs, you'll need to compare the rates of heating engineers in your area.

But how do you get quotes from heating engineers quickly? And how do you know if they're qualified? Don't worry – Household Quotes can help.

We have a large network of vetted heating engineers across the UK. By filling in a short form, we can easily connect you with up to 3 qualified installers in your area. Each installer will provide you with a free, non-binding quote, which you can then compare to choose the best deal.

To get your boiler sizing right from the beginning and avoid wasting your hard-earned money, click the button below.