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What size electric boiler do I need?


If you have been scouring the market for a new boiler, you might know the process can be pretty challenging. So, selecting an electric boiler is not as simple as reciting a nursery rhyme. You need to strike the right balance or the ‘Goldilocks formula’ for a boiler that’s just the right size. A boiler that is too big will send your electric bills rising through the roof. In contrast, one that is too small will not heat your home sufficiently. If you want to avoid burning a hole in your wallet or feeling an uncomfortable draft of chilly wind even with the boiler on, then read this comprehensive guide on what size electric boiler do I need? Alternatively, why not refer to our boiler installation service page to learn more about the services we provide.

Contrary to common misconception, the size of a boiler does not refer to its physical dimensions. It relates to its energy output or kilowatt (kW) rating, like a gas boiler. If the kW rating is higher, the device can supply energy to more radiators, taps, and other heating systems. Unlike gas boilers, whose highest energy rating is around 35 kW, electric boilers only have a maximum rating of 15 kW. Hence, these are only suitable for small homes or apartments, not commercial spaces or large residences. At the same time, why not check out our Boiler Installation service on our homepage and learn more about what we offer.

Boiler Servicing and Maintenance

We believe that your safety and the safety of your home is of utmost importance during a boiler service or any other gas appliance-related work. Our customer-first approach is what has allowed us to build up a stellar reputation over the last decade. The only way to ensure that your boiler or appliance is functioning efficiently and safely is with regular maintenance and professional servicing, which are usually carried out annually. There are a number of reasons to get a yearly service.


What size electric boiler do I need for hot water?

The electric boiler size for supplying hot water taps mainly depends on the distance between the hot water tank and the taps. Also, it depends on the piping material and the efficiency rating of the tank. A cylinder stores the hot water heated by a boiler inside the tank. Ideally, this water should be warm for at least a day or more if the water tank is efficient. To be extra safe, you can buy an insulation cover for the tank and any pipes connecting it to taps. Hence, a tank made from high-quality material is essential.

Good insulation can also prevent the loss of heat. Since there are too many variables, including external temperatures, estimating the boiler size for taps might be hard without seeking professional advice. Alternatively, if you have been wondering about replacing gas boiler with electric, then our blog on this exact topic will give you a better idea.

How to determine the size of the boiler?

To determine the size of the boiler, you would need to count all the radiators in your home. As a general rule of thumb, each radiator accounts for nearly 1.5 kW of energy. So, add this amount to every radiator the device will supply energy to. In turn, if you have five radiators, you would require a boiler rating of at least 7.5 kW. However, it is essential to remember that this is just a general approximation. Factors like window glazing, insulation efficiency, and space volume also affect a boiler’s efficacy. So, if you are unsure, it is best to consult an expert.

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Electric boiler size for underfloor heating

Underfloor heating systems are becoming increasingly popular as the world is moving toward eco-friendly concepts that do not pull in too much energy. This type of central heating system underneath floors offers several benefits. Apart from freeing up floor space that a radiator would otherwise occupy, this system can help you save nearly a quarter of your electricity bill. It’s easy to maintain and can heat your home to an optimum level without hassle.

The size of an electric boiler for this system would depend on variables like floor space, type of flooring, and house layout. Ideally, this central heating system requires a flow temperature of about 40-50°C to work well. So, a boiler of at least 6 kW would be required. However, it is best to consult an expert before investing in one. However, you can also read about it on our blog titled how to lay electric underfloor heating.

Choosing the right electric boiler size is no cakewalk. Furthermore, the question of “what size electric boiler do I need?” is not easy to answer. The entire process can be quite overwhelming. A boiler that is too small boiler might not be powerful enough to provide sufficient heat, enough to keep the house’s occupants warm. On the other hand, one that is too big will drastically increase your electricity bills. Hence, it is best to consult a team of professionals before making a hasty decision. Our team can account for all your needs and help you choose the right boiler according to your budget. At the same time, while we’re on the topic, check out our blog on how long does it take to install an electric boiler?

Are electric boilers efficient?

Before you ask the question, “What size electric boiler do I need?” it would help to know what an ErP score is. An ErP score or rating is indicative of the energy efficiency of all types of boilers. So, a boiler with an Energy-Related Products score of G is the least efficient. Subsequently, if it has a label of A+++, then it means that it is highly efficient. As mentioned above, electric boilers are about 99% efficient, making them a popular choice. However, they only have a score of D at best.

That is because they require fossil fuels to be burnt to produce electricity. This process generates twice the level of carbon dioxide relative to natural gas burnt for gas boilers. Electricity is also heavier on the pocket than gas. This combination of factors gives them a low ErP score; barely any energy is lost during their operation. An alternative would be to run a boiler that derives electricity from solar panels. It could also reduce your electricity bills significantly.