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Boiler Types Explained


Lee Devlin

Published on: 08/10/2019
Heating System Boiler Types image

One of the most common questions we are asked at Homecure is “What is the best boiler type for my home?” There are a number of different boiler types available and the right one for your property will depend on your energy source, size of home and heating and water requirements.

Below we explain the differences between the main boiler types and the advantages and disadvantages of each one. It will tell you which boiler is more cost and energy efficient and environmentally friendly, so you can make an informed choice for your home.

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Condensing Boiler

Condensing Boiler
Condensing Boiler Example (Worcester)

A condensing boiler isn’t necessarily an individual type of boiler. In fact, any type of boiler installed in the UK since 2005 must be condensing. The reason for this is because it helps to improve energy efficiency, by lowering your carbon footprint and utility bills at the same time. Condensing boilers are viewed as being the most energy efficient and play an important role in creating homes that are kinder to the environment.

Condensing Boiler advantages

Energy and cost efficiency: Condensing boilers are categorised as being 90% more efficient than older styles previously installed in UK homes. Aside from being kinder to the environment, the benefits for your home also mean you enjoy a better source of heating. They are generally a little more expensive, but the money saved on bills over the years should balance things out in the long run.

Compact design: Condensing boilers are ideal for smaller homes as there is no need to install a water storage tank. When it comes to the size of the boiler itself, there are plenty of compact designs available, restricting the amount of space they will physically take up.

Condensing Boiler disadvantages

Frozen pipes: These types of boilers require a condensate pipe to run to an external area of your home, and during winter they can be affected by the cold weather. If the condensate pipe freezes over it can stop the boiler from working, however, pouring warm water over the pipe helps to thaw it out and is usually enough to fix the issue.

High maintenance costs: The engineering that goes into a condensing boiler means they are made up of many complex parts. When it comes to providing maintenance they can be more costly to repair because of this. That’s why it is vitally important to have the boiler serviced once a year by a Gas Safe registered engineer to avoid any problems.

Combi Boilers

Combi Boilers
Combi Boiler Example (Worcester)

Combi boilers are probably the most popular type of boilers installed in the UK. This is because they remove the need for water tanks or cylinders in the home, while still ensuring you have access to hot water and heating whenever you need. Combi boilers can either be gas or electric-based, depending on the current set-up of your home. They are also viewed as being extremely energy efficient, meaning not only do you save space due to no tank installation, but utility bills are also lower, saving you money in the process.

Combi Boiler advantages

Small design: Combi boilers are generally smaller in design compared to most other types. They also do not require storage tanks, so people living in flats and compact homes will be able to enjoy a great heating system without having to sacrifice too much space in return.

Cost and energy efficiency: Combi boilers ensure you only heat the water you need to use, which means much less energy is wasted, while also keeping your energy bills lower right across the year.

Strong water pressure: Having an efficient boiler is no good if the water pressure coming out of the taps is not strong enough. Luckily, combi boilers should give you just that, as long as the mains pressure is at an acceptable level.

Short installation times: Ideally you want a new boiler fitted as quickly as possible and a combi boiler is quick and easy to install. When it comes to repairs and maintenance, they are straightforward to fix, keeping costs low and manageable.

Instant hot water: There is no need to wait for the water in a tank to heat up, as combi boilers provide constant hot water whenever it is needed.

Combi Boiler disadvantages

Shower compatibility issues: If you have a power shower installed, these are not designed to work with a combi boiler due
to the water pressure being determined by the mains.

Mains level problems: Before installing a combi boiler you should make sure you have a good flow rate through the mains supply to get the most out of the system. An alternative option may be best if this is not the case.

Only one source of hot water can be used at the same time: If you have more than one bathroom, a combi boiler won’t let both receive hot water if a shower/bath/tap are being used at the same time. Which is not ideal if more than one person needs to use the hot water.

System Boilers

System Boilers
System Boiler Example (Biasi)

System boilers are sometimes referred to as a sealed system, and they come with a water cylinder (situated in an airing cupboard) but no water tank. They tend to be a good choice for homes that have more than one bathroom as it provides a constant supply of hot water. System boilers are also a good option for homes without a loft, or where you may want to convert part of the home that features an existing heating system. For the really environmentally conscious, they can also be used in conjunction with solar water heating systems, while also generally providing great levels of energy efficiency.

System Boiler advantages

Easy to install: Compared to some other types, system boilers already contain many of the components needed to make the heating system function properly, making the installation process very straightforward.

Use more than one source of water: If you live in a large property and need to run more than one bath/shower/tap at the same time, it won’t cause any issues due to the presence of the storage tank.

Works with solar thermal panels: Households that have solar thermal systems installed will find that system boilers are compatible. This offers another way to reduce your carbon footprint and money spent on energy bills.

System Boiler disadvantages

Not small in size: A system boiler needs a hot water storage tank in order for it to work, so it is not suitable for smaller homes that do not have the space.
Heat loss: The longer hot water remains in the storage tank, the lower the temperature becomes. It should be insulated to extend the length of time the water retains the heat, although this comes at an extra expense.

Limited hot water: The size of the water tank you have installed will dictate how much water is available at any one time. Once it runs out, you have to reheat the water from the start before it can be used again.

Regular Boilers

Regular Boiler
Regular Boiler Example (Worcester)

Regular boilers may also be called conventional, regular, heat only or open vent boilers, depending on who is supplying them. They feature both a water cylinder and a water storage tank. You’ll usually find these in larger properties that have more than one bathroom, or for families that need a constant supply of hot water. Regular boilers work best in older properties that have traditional heating systems already in place. This makes installation easier, and any changes required tend to be small. Energy efficiency wise they work very well with solar heating systems to reduce bills and carbon emissions.

Regular Boiler advantages

Multi-usage: More than one shower/bath/tap can be run at any one time without affecting the water temperature or pressure, as it all comes from the water cylinder.

Great replacement system: Installing a regular boiler in place of an older system usually means very little pipework has to be carried out, making it a relatively hassle free process to go through.

Works with immersion heaters: You can install an electrical immersion heater into the water cylinder, ensuring you have a back-up should the boiler break down unexpectedly.

Regular Boiler disadvantages

Lots of space needed: Smaller homes generally don’t tend to have a regular boiler as both a loft and airing cupboard is needed to store
the various components.

Water temperature loss: Hot water temperature will only be maintained for a certain amount of time before it starts to cool and will need to be
reheated to reach its peak again.

Heating times: You have to wait for a regular boiler to heat the tank before you can enjoy hot water. This means regulating how much you use
through the day before it has to be reheated.

Installation issues: It generally takes a longer time for companies to install a regular boiler as there is more pipework and separate parts that need to be fitted.

Gas Boilers

Gas Boilers
Gas Boiler Example (Baxi)

As there are over 23 million properties in the UK that rely on gas, it’s no surprise that most homeowners tend to opt for gas boilers in their home. Gas boilers refer to the fuel being used to provide the heating, rather than a type of boiler – which is why regular, combi and system boilers can all be installed using gas.

Gas Boiler advantages

Cheaper costs: Per kWh, gas boilers are considered to be up to 3-4 times cheaper to run compared to electric boilers. This means you get more for your money as they are more cost efficient.

Environmentally friendly: Gas is still harmful to the environment but it is the cleanest fossil fuel available to heat the home. Compared to oil it emits less than half the amount of CO2 and a third less compared to coal.

Gas Boiler disadvantages

Gas connection: If you are not already connected to the gas grid, then you cannot install a gas boiler. Connecting your home to the gas grid isn’t free, so it becomes an extra expense you have to account for.

Electric Boilers

Electric Boiler
Electric Boiler Example (Strom)

Although gas boilers are the most popular in the UK, millions of households have electric boilers installed in their homes. They are the logical choice for properties that are not connected to the gas network and work best in smaller homes. The heating element contained within an electric boiler warms the water that passes through before being sent on to the tap in use. Compared to gas boilers they are seen as being less wasteful as they reduce the amount of heat lost during the process.

Electric Boiler advantages

Energy efficient: Electric boilers do not lose heat as gas boilers do, and almost offer full efficiency at all times. That means you maximise the amount of heat in the water for a longer period.

Easy installation: The technical make-up of an electrical boiler is not overly complex. This makes them cheaper and easier to install and they don’t take up too much room. They are also safer than gas boilers as there isn’t the same level of carbon monoxide risk.

Electric Boiler disadvantages

Running costs: Installing an electric boiler will significantly add to your electricity bills. Gas is cheaper than electricity, so you should weigh up whether it is worth paying to join the gas grid or staying electric.

Better for smaller homes: Anyone living in a larger property probably won’t get to enjoy the full benefits of an electric boiler. If you have a large family, you’ll get through a lot of water and an electric boiler won’t be able to keep up with the demands placed upon it.

What sort of boiler do I need for my home?

Every home is different, as are the people that live there. That means your requirements are unique and you need a boiler that can meet your demands and not let you down. In most cases, anyone living in a smaller property with a single bathroom should install a combi boiler. Whereas, larger properties that have more than one bathroom work best with system boilers and regular boilers.

Have you considered? If your central heating system or boiler is less efficient than it should be, it may be suffering from a blockage or build up. If so, we can help.

Our multi-skilled engineers also carry out boiler installations so if your old one has given up, or you’ve decided to change your boiler, give us a call. We are very familiar with all varieties of boiler brands, including Vaillant, Worcester, Bosch, Potterton, Baxi, Alpha boilers, Vokera and many more. We’ll install your new boiler with minimal fuss and at a price that’s favourable to your pocket.

To get an expert opinion, get in touch with our team today or request a callback.

Lee Devlin
Publication date: 08/10/2019

Lee Devlin is the managing director of Homecure Plumbers, London's favourite local plumbing service. Since 2009, Lee's been leading a large team of gas safe plumbing and heating engineers as well as growing a successful business built on quality customer service and workmanship, in a competitive industry within the Capital. He's been in the game for a long time, so he regularly shares his knowledge and experience with the public. His expert tips have been featured in lots of well known publications such as: The Sun, Metro, Insider, Homes And Gardens, Country Living and more!

Read More About Lee Devlin.

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