Which combi boiler do i need

Toggle Nav. Deals by type Deals by brand. Google Nest. Coffin tanks. HomeScale Protect. Horizontal Radiators Vertical Radiators. Garden Tap Project. Portsmouth Erith Dagenham Billericay Croydon Park Royal Tamworth Glasgow Bristol What size combi boiler is best for my house? Combi boilers are available in three size ranges here at Mr Central Heating; 24 to 27kw , 28 to 34kw and 35 to 42kw. It also helps with energy efficiency in the home, What is a Combi boiler? Our Newsletter Sign-up to get news on the best offers.

Sign up. If, however, you have multiple bathrooms that are likely to be in use at the same time, a system boiler that stores hot water in a storage cylinder may be more suitable.

As well as providing your hot water, your boiler will probably be the main source of heating for your property. This means that it is essential to choose a boiler that is large enough to provide sufficient heat output to supply your entire property.

Domestic boiler size is measured in terms of heat output, which typically ranges from 5 to 35 kW. For conventional and system boilers, you should avoid choosing a boiler that is too big for your home, for example, installing a boiler that has a capacity to supply 15 radiators when your flat only has a few. This will only result in a more costly energy bill and is a waste of gas and electricity.

For combi boilers, the boiler size is usually determined by the hot water demand, a qualified heating installer will assess this for you prior to final recommendation and fitting. Not only is this a waste of energy but you could receive an unexpectedly high bill from your energy supplier. There is a calculation that can be used to work out how much heat your property is losing. It takes into account the area of the room, the number of radiators, the quantity of doors and windows and the quality of insulation in your home.

An expert is able to calculate how much heat your house will lose on the coldest day of the year and use this information to work out the optimum boiler size. In the past, it was common practice to choose an oversized boiler that was as much as 30 per cent bigger than required. However, with advances in technology, this is no longer necessary and will only result in wasted energy, leaving you out of pocket.

Oil boilers should be considered too. You may even want to look into green energy sources, however, these will have an impact on your choice of heating system and boiler, too. The most common fuel type in the UK is mains gas, with the majority of UK homes already connected.

With a gas boiler there is a constant supply and as far as non-renewable energy is concerned, it is considered to be the cleanest type of fuel. Oil is the most common alternative for properties that are not connected to the gas network and is currently used by an estimated 4. Unlike gas combi-boilers, oil boilers tend to be non-condensing and floor standing, therefore may require more space. They also tend to offer a lower hot water flow rate in comparison. Finally, consider biomass and other forms of alternative energy.

A more eco-friendly, alternative choice, these boilers are powered by a sustainable fuel source. Typically fuelled by wood pellets, chips or logs, they can help to protect the environment as well as saving on your energy bills.

Other alternative approaches to energy for your boiler that are seeing increasing popularity are are air source heat pumps , ground source heat pumps and fuel cell technology which are increasingly compatible with modern boilers. You may also wish to consider whether your boiler is designed with future energy sources in mind.

Coldwater is fed to the boiler from the tank in the loft before it gets heated and then circulated to the central heating system or hot water cylinder. Regular boilers are not recommended unless it is to replace an existing regular setup.

It is considered much more beneficial to upgrade to a combi if it becomes time for a replacement. If you have any doubt about the most suitable boiler for your home and heating needs, a heating engineer will be able to recommend the right one. You can get an idea of what you need based on the size of your home and the amount of hot water you need.

Combi boilers are bigger in size than system and regular boilers as they need to produce hot water on demand for domestic use as well as heating. As they directly provide central heating and domestic hot water, they have two separate output ratings:. Regular and system boilers only have a central heating output as the domestic hot water is stored in a cylinder. The central heating outputs of combi boilers can be split into three categories to help you find a suitable model depending on the number of radiators in your property.

Find out more about the Best Combi Boilers. System and regular boilers do not need to be as powerful as combi boilers. This is because they incorporate a separate hot water cylinder for heating and storing domestic water. Adding up the number of radiators around your home will help you understand a suitable system boiler output rating. Get a complete overview of system boilers in our What is a System Boiler? Pros, Cons and Costs article. Compare the best boilers with our Boiler Comparison Tool.

You can also call a professional installer who will be able to measure the flow rate and temperature of your mains water for you. Find out more about combi flow rate here. Replacing your boiler should increase the energy efficiency of your home which can, in turn, reduce your energy bills. We've got some extra tips to help your boiler work as efficiently as possible. To get an accurate idea of the appropriate boiler sizing for your home, we highly recommend seeking the advice of a professional heating engineer.

Comparing multiple quotes will help you to find the most suitable boiler for your home at the most competitive price. When your boiler is not being used for central heating or hot water, it turns itself off, which means the water used to provide us with heating and hot-running taps will cool. When it is called into use again, an oversized boiler will use more power than a properly sized boiler to heat the same volume of water — the amount your household needs to use. A boiler that is too small will not be able to keep up with the demand for water and heat that your property needs.

That could lead to you waking up in a chilly house and stepping into freezing cold showers in winter, which is no good for anyone. Here at Ideal, you can find 12kW boilers in our heat only range, and 15kW in our heat only and system models. Small but powerful, we recommend that boilers between 12 and 15kW are the perfect size for heating a home with up to 10 radiators.

At this size, an 18kW model is powerful enough to run between 10 and 15 radiators, making it ideal for medium-sized properties. The number of radiators a 24kW boiler can heat will depend on the type of model you require. As a guide, combi boilers between 24 and 27kW can power up to 10 radiators, while a 24kW heat only or system model can heat up to 15 radiators.

For combi boilers, sizes from 28 to 32kW can keep between 10 and 15 radiators nice and toasty. On the other hand, 30kW heat only and system boilers can heat 15 to 20 radiators, making them the ideal choice for running larger properties.