Boilers can seem complicated, especially if you’re making the decision to get a new boiler installed; you’re probably unsure where to start.
Most houses in the UK fall under a few common boiler types, and what’s right for you usually comes down to both your home’s plumbing and personal preference.
That’s why in this guide, we’ll break down the different types of boilers in plain English. Specifically, what each one is, how they work, and the pros and cons of each.
What is a combi boiler?
A combi boiler is the most common type of boiler for small to mid-range houses. Combi “combination” boilers combine your central heating and hot water into one unit, without needing a separate hot water cylinder or a cold water storage tank.
How do combi boilers work?
Combi boilers have hot water on demand.
When you turn the heating on, the boiler heats water and sends it through your radiators.
When you open a hot tap, the boiler switches to hot water mode and heats mains water through a heat exchanger as it flows through.
Because hot water is made as you use it, there’s no stored hot water sitting in a cylinder, meaning you usually save space and reduce heat loss compared to stored systems.
The pros and cons of combi boilers
Combi boilers are perfect for small to medium homes with one or two bathrooms.
The typical combi boiler is small enough to fit inside a standard-sized kitchen cupboard, and because everything is contained in one unit, you don’t need to find room for a hot water cylinder or storage tank.
The main issue with combi boilers is their lower power output, which makes them pretty difficult to use in large homes with multiple bathrooms, multiple people, and high hot-water demand.
Using taps at the same time with a combi boiler can reduce performance and heat output from one tap, which can be frustrating.
With combi boilers, if your house is relatively modern, you prioritise space-saving and don’t require high-demand hot water, then combi boilers are likely your go-to.
However, a family of five with three bathrooms, who are likely to use the bathroom’s facilities at the same time, would most likely want to consider a different option, such as a system boiler.
What is a system boiler?
A system boiler sits in the middle ground between a combi and a regular boiler. It still powers your central heating, but it also works with a hot water cylinder, which means you’ve got a stored supply of hot water ready to go.
The pros and cons of combi boilers
System boilers are usually a better fit for homes with a higher hot-water demand.
Because they store hot water in a cylinder, they deliver a more consistent supply to multiple taps or multiple showers at the same time, without the same drop-off you can get with some combi setups.
With system boilers, you also don’t need a loft tank, which keeps the system simpler than a traditional regular boiler.
The trade-off is that you do need space for that hot water cylinder, and if usage is heavy, the stored hot water can run out, leaving you to wait for it to reheat.
There’s also some unavoidable heat loss from storing hot water, and installations can be trickier and more time-consuming than a straightforward combi boiler swap.
What is a regular boiler?
A regular boiler (also called a conventional boiler) is the more traditional boiler setup found in older UK homes.
It powers your central heating but works with a hot water cylinder, so you’ve got a stored supply of hot water rather than it being made instantly, like a combi – similar to that of a system boiler.
The big difference between a system and a regular boiler is that most regular boilers also need a cold-water storage tank (often in the loft), which feeds the hot water cylinder and helps supply your taps.
The pros and cons of regular boilers
The pros of a regular boiler are similar to those of a system boiler. They’re great options for homes with high hot water demand, and you can run more than one tap without experiencing a drop in performance, an issue you may come across with a combi boiler.
They also make sense if your home already has the cylinder and tank setup in place, because replacing a regular boiler is a simpler task than changing the whole system.
The trade-off is that they take up more space (you’ll need room for the cylinder and typically a loft tank, so you’ll have even less space than you would with a system), and you’ll need to wait for the cylinder to heat back up if you use up all the hot water.
Similar to system boilers, you’re likely to experience unavoidable heat loss from storing hot water, and the installation process is also more challenging.
What is an electric boiler?
An electric boiler does the same basic job as a gas boiler, like heating your radiators (and sometimes your hot water too), but – as you’d guess – it uses electricity instead of burning gas.
Inside, it heats water using electric heating elements, then pumps that hot water around your central heating system.
Electric boilers can be set up in a couple of ways: some work like a combi (hot water on demand), and others work with a hot water cylinder (more like a system/regular setup). In the UK, you’ll often see them used where there’s no gas supply.
The pros and cons of electric boilers
Electric boilers make sense if you want something compact, quiet, and straightforward.
Electric boilers are easier to install and maintain than gas boilers because they don’t need a flue or gas safety checks. They’re ideal for small homes, like flats, and can be cheaper to run if you have solar panels.
However, running an electric boiler is usually more expensive than running a gas boiler because electricity costs more than gas.
They can be very costly to heat larger homes or homes that use a lot of heating and hot water. Sometimes, you might also need to upgrade your home’s electricity system to support a larger electric boiler.
A final note – what’s best for your home?
Choosing the right boiler really comes down to two main things: how much hot water you use and whether you’ve got space for a hot water cylinder.
As a general guide, combi boilers tend to suit small-to-medium homes with one bathroom, system boilers are often a better fit for larger homes because of their stored hot water, regular boilers are the easiest option – if you already have that set up, and electric boilers are worth considering if you don’t have a gas supply, just bear in mind they can cost more to run and install.
