What Size Boiler Do I Need?

Illustration of varying property sizes/type & corresponding boiler sizes

When it comes to our central heating systems and our homes, boilers are probably one of the most expensive items in our houses. It can be tempting therefore to cut costs when it comes to picking a boiler to help save money. Often, people will try to install a smaller boiler than they need as a result. However, this actually ends up in costing more, as a smaller boiler than a home needs is an inefficient allocation of funds and energy.

Here, we look at why that is by answering what size boiler do I need so you can figure out how to calculate boiler capacity and calculate your own boiler size.

Types of boiler systems

Before outlining how to calculate boiler capacity, it is first helpful to know what types of boiler systems there are out there to choose from. The system you choose will be affected by the type of house you live in, where the boiler will go, your heating needs, and your budget.

Conventional boilers

Conventional boilers are part of traditional heating systems. They work by having a hot water tank and a cold water tank. The system takes the cold water from the cold water tank, and heats it and stores it in the hot water tank. When a hot tap is turned on, the hot water comes from the hot water tank immediately. The same occurs when the heating is turned on.

Combi boilers

Combi boilers have surged in popularity in recent years as they answer many demands of modern living. They work by heating water when required and as such can be used as a boiler as well as a home's water heater. Thus, there is only one hot water system so it is meant to be a simpler system to run. The reason that they may not - despite their many advantages - be suitable for all is that they often cannot heat water required in different places. So if someone wants a hot shower while the heating is on, they may not be able to until they turn the heating off. 

System boilers

A system boiler is a good option for those that have a large home or property to heat. The reason being is that bigger sized properties need a bigger amount of water, which a system boiler can cope with. System boilers take water straight from the mains and then heat it and store it immediately. There is no cold water tank, so water is hot immediately as soon as a tap is turned on.

How to calculate boiler capacity

You need to consider a number of factors when trying to find the right boiler for you. Do so objectively so that you end up getting a boiler with the capacity you need.

Firstly, look at your property size. If you live in a one bedroom flat, you won't need the largest boiler on the market. Secondly, identify the number of radiators you have in your home. The more radiators you have, the bigger the boiler you need to run hot water through them. Then, think of the amount you use the bathroom in your home. If you have more baths than showers, you may want a bigger boiler. Or, if you find that you use the showers at the gym a lot, that will affect your hot water usage too. After that, consider bathroom usage by other individuals in your home. Do you have a big family or lots of roommates? If you do, you'll need a bigger boiler. Finally, if your home is over a large number of floors, you'll want to choose a boiler that can stand up to the work that is required of it. To provide good water pressure on the top floor will require a powerful boiler.

Getting your boiler size right is key as it means you will have the most efficient heating system while also keeping your costs low. Buying a boiler that is too big for your needs will mean you are heating water at a rate you do not require, or buy one too small and it will not answer the demands you make of it. The result is you may overwork it, so its shelf life is longer.

For all these reasons, it can be highly beneficial to get some advice from a trained professional. By working together with an experienced plumber, you'll be able to balance the needs of you and your family as well as the property you live in, with the budget you have available to you.

Check out our range of radiators today if you are looking at overhauling your entire central heating system. By choosing good quality, highly-effective radiators, you can help the overall efficiency of your entire central heating system - thus reducing the size of the boiler you need. If you need a hand, give us a call.


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