Your boiler is one of the most important household appliances. Every responsible homeowner knows that in order to have an efficient heating system, they need the right type of water heater, most suitable to their household’s needs. But if you’re moving into a brand new building, how do you know what kind of boiler you need? Fear not, because Fantastic Services is here with the answers!
This article is for all of you homeowners who:
First thing’s first, when we say boiler size, we don’t mean the physical dimensions, but the output in kilowatts (kW). A kilowatt is a unit that measures how much energy in the form of heat the boiler outputs. The bigger the demand for heat and hot water, the higher the output. So, when you’re on the market, looking for your next boiler, this is the main criteria you should consider. But how do you know what the demands of your new household are?
There are three main types of modern household boilers. All of them would do a great job in heating the water you use in the shower, as well as keep your heating system going. However, if you’re searching for greater efficiency, you better read on.
The more baths and showers you have, the larger boiler you will need. And of course, don’t forget the number of radiators around your house. Below, you will find general advice on what boiler size you need according to these three criteria.
Not sure what size to pick? Need your boiler installed? Visit our website to check out price rates for boiler installation!
If you’ve decided to get a combi boiler for your new household, here is the size you need according to your property’s size and heating system.
| Showers/baths | Radiators | Boiler size |
| 1-2 | Up to 10 | 24-27 kW |
| 2-3 | 10-15 | 28-34 kW |
| 3+ | 15-20 | 35-42 kW |
If your household has three or more bathrooms, you’ll be pushing the boundaries of a combi boiler’s efficiency. That doesn’t mean it won’t work well, but you’ll have a much better experience if you opt for a heater with a water cylinder instead.
If a heat-only boiler is what your household needs, make sure to pick the proper size from the table below.
| Showers/baths | Radiators | Boiler size |
| 1-2 | Up to 10 | 9-18 kW |
| 2-3 | 10-15 | 18-26 kW |
| 3+ | 15-20 | 27-40 kW |
For system boilers, here is the size you need according to your property’s size and heating system.
| Showers/baths | Radiators | Boiler size |
| 1-2 | Up to 10 | 9-18 kW |
| 2-3 | 10-15 | 18-26 kW |
| 3+ | 15-20 | 27-40 kW |
As you can see, the output from a heat-only or system boiler is generally the same. They also don’t need a higher output size like combi boilers thanks to their hot water cylinders. If you’re sure your household needs a heater with a water cylinder, it’s mostly a question of price. For more information, check out our article on how to choose a new boiler.
If you’ve settled on either a system or a heat-only boiler, know that the cylinder size is just as important as the boiler size. Again, when we say size, we don’t mean physical dimensions. In this case, we refer to water capacity. This would depend on the number of occupants of the property and the number of bathrooms or showers.
Hot water cylinders can be vented or unvented. Vented cylinders take water directly from the mains. This requires them to be installed alongside a system boiler. Unvented cylinders receive water from a cold water tank which means you should install them with a heat-only boiler.
The cylinders can also be heated directly, or indirectly. Indirect heating means the boiler itself heats the water. Direct heating means water is warmed up by an immersion heater. These heaters are placed within the cylinder and can work with the help of solar panels for lower energy costs. Here is a general guide on choosing the right hot water cylinder.
| Occupants | Showers/Baths | Indirect | Direct |
| 1 | 1 | 75/120 litres | 120/150 litres |
| 2 | 1 | 150 litres | 180 litres |
| 3 | 2 | 180 litres | 210 litres |
| 4 | 3 | 210/250 litres | 250/300 litres |
Are your boiler and heating system healthy? Sometimes, you might not need a new boiler, but you just have to take care of an issue that prevents it from working properly. Always make sure a reliable boiler technician checks your boiler before taking a big decision like looking for a new one. If you’re not sure about what’s wrong with your current water heater, give a call to the professional team of plumbers at Fantastic Services.
They will check the problem and advise whether it’s time to retire your appliance. If this is not the case for you, that’s even better, but why wait for your boiler to fall short of your expectations, you can subscribe to one of our boiler cover or central heating plans and have a technician any time you need him at no extra cost. Our plans include repair costs, annual check-up and much more.
Reach out to a reliable boiler technician now!
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Have you ever been in the market for a new boiler? Tell us about your criteria in the comments and how satisfied you are with the purchase!
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