What is a combi boiler?

A combi (or combination) boiler is by far the most common type of boiler. A combi boiler system's simple design requires little space in your home and supplies hot water directly to your taps or radiators without the need for a storage tank. The chief advantage of a combi boiler is its economy.

What's the difference between a combi boiler and a normal one?

Combi boilers are compact, quick to install, and they provide hot water on demand. They don't have storage tanks or cylinders, which makes them ideal for small homes. Conventional boilers, on the other hand, are ideal for large households. They work with a water tank and a cylinder.

What are the disadvantages of a combi boiler?

Are combi boilers gas or electric?

An electric combi boiler performs all the usual tasks of a gas combi boiler, but using only electricity to power your central heating and hot water. You can use an electric combi boiler for hot water only, but usually it will meet all of your heating needs.

Are combi boilers a good idea?

Combi boilers are great when you have relatively small hot water demand at any one time. If you require hot water feeds in multiple outlets at the same time– say that you want to run 2 showers at the same time in the morning, then a combi boiler won't be suitable.

What is a Combi Boiler?

Can I have a power shower with a combi boiler?

Combi boilers are incompatible with boiler pumps, which means that power showers cannot be installed with a combi boiler system. Electric showers can, however, help improve the water pressure in a shower slightly. System boilers and regular boilers can be connected to power showers.

Do I need a cold water tank with a combi boiler?

Space Efficient – A Combi boiler is very convenient, because –unlike the traditional boilers– it does not require a hot water storage tank, or a cold water feed tank.

Can combi boilers heat water and radiators at the same time?

The control valves within combi boilers work in different directions to one another. Therefore, the system will either transport hot water to your radiators or to your hot water tap – however, this will not be done at the same time and the hot water circuit usually takes priority.

Can you have a hot water tank with a combi boiler?

If you want a way to store the water that your combi boiler heats, you could invest in a storage combi boiler. A storage combi boiler merges the technology of a combi boiler with that of a system boiler. However, you don't need space to house a hot water tank as the boiler has a small storage tank built into it.

Do combi boilers use water?

Combi boilers work by taking water directly from the mains supply to provide instant hot water to taps and showers at a strong pressure. As compact units that don't need any external tanks or cylinders, one of the reasons why combi boilers have become the boiler of choice for homeowners across the UK.

Do combi boilers run out of hot water?

Since combi boilers don't have to store any hot water, the heat losses via the hot water tank are zero, helping save you money on your gas bills. Most boilers installed today are condensing boilers, so if you choose a combi boiler, this will be a condensing model.

Do I need a room thermostat with a combi boiler?

If it is a 'combi' boiler and provides instantaneous hot water then no additional controls are needed. If you have a separate hot water cylinder then there should be a thermostat on the cylinder to turn the boiler off when the water is hot enough. Also, there should be some form of time control for the hot water.

Can a combi boiler heat a large house?

The truth is that even the smallest combi boilers will heat most larger homes and the best solution for you might not be a combi at all. The real driver for selecting the right boiler for a larger home is your hot water requirements. If you need lots of hot water, a hot water cylinder will be preferable.

What will replace gas boilers in 2025?

In 2025, gas boilers will be replaced by renewable heating systems in all new-build homes. This is part of a government effort to achieve net-zero CO2 emissions by 2050.

Is a combi boiler cheaper to run than a system boiler?

If we compare a system boiler vs combi boiler running costs, then it is likely that a combi boiler will be more efficient and so offer some savings. However, if a combi isn't able to provide the volume of hot water you need, then getting a combi boiler is pointless as it will not be able to heat your property.

Is a system boiler more expensive to run than a combi boiler?

The system boiler is cheaper than a combi boiler but still more expensive than simply repairing your old system. System boilers reviews prove that they're cheaper and better. Typically the costs for sealed combustion boilers are higher than for traditional atmospherically vented boilers.

Why have I got a combi boiler and a water tank?

Combi boilers heat water directly from the mains when you turn on a tap, so you won't need a hot water storage cylinder or a cold water storage tank in the roof space. They are also very cost-effective and energy-efficient as water is heated instantly rather than being heated and then stored in a cylinder.

Does a combi boiler have a tank in the loft?

Combi boilers have an <u>expansion tank</u>, usually located inside the boiler casing (but can be fitted elsewhere on the system).

What is involved in changing to a combi boiler?

Changing to a combi boiler - the process explained:

Drain the existing central heating system, including boiler and radiators. Remove the existing/old boiler. Remove cylinders and header tank (in the attic). Upgrade the gas pipework to 22mm.

Where does a combi boiler go?

Does a combi boiler need to be located on an external wall? Your boiler can be fitted on any wall, internal or external, as long as the wall is strong enough to take its weight when full of water. The boiler's flue must be able to pass to the outside, either through an outside wall or through the roof.

Do I need a central heating pump with a combi boiler?

A combi boiler doesn't need a pump for your hot water. This is because the hot water that is supplied to your taps and showers is at mains pressure. This usually means that, if your area has low mains pressure, it's advised that you have a conventional boiler instead of a combi.

What showers work with a combi boiler?

Mini valve, maxi valve, bar valve and concealed valve showers are all compatible with combi boilers. The only ones that aren't compatible are power showers and this is because they contain an in-built pump that is not suitable to be connected to pressurised water supply from the mains.

Is it worth swapping to a combi boiler?

One of the most important reasons for changing to a combi boiler is energy efficiency. According to the Energy Saving Trust, replacing a 12-15 year older boiler with a new A-rated condensing combi boiler can save you up to 40% on your energy bills.

How much does it cost to change a water tank to a combi boiler?

Cost of installing a combi boiler and removing the water tank. To replace your heating system with an efficient combi boiler and remove the old water tank, you can expect to pay around £2,800.

Will a combi boiler save me money?

If your boiler is over 10 years old, look into its efficiency - essentially how much energy it's actually making use of and turning into heat and hot water for your house. You're likely to be shocked. Upgrading to a new modern combi boiler is likely to save you between 20-35% on your gas bills.