What is a gas boiler?

What is a gas boiler and how does it work?

Gas boilers are widely-used options for powering central heating in homes up and down the UK. They’re an efficient way to guarantee reliable performance from your home heating system and are simple to install and use.

Gas boilers can be used to provide hot water for your home, as well as for your central heating system. They operate in three simple steps; this increases to four if you have a condensing gas boiler installed in your home.

• Your home boiler burns natural gas or propane
• The fumes generated in the burning process circulate around an exchanger, through which the water used in your home central heating and hot water taps flows
• This water heats up, warming up your home radiators and providing hot water for your sinks, shower, bath, and so on
• If you have a condensing gas boiler at home, this will condense the combustion gases and water vapour produced in the burning process to reutilise their latent thermal energy (this makes condensing gas boilers a more energy efficient, environmentally friendly option)

Gas boilers: key advantages and disadvantages

There are many plus points to installing a gas boiler in your home - with only a few drawbacks. We’ve outlined the key factors to bear in mind below:

Advantages of gas boilers

• Efficient, economical and space-saving boiler option for your home heating
• Easy to install in your home, during renovations and in new builds
• More environmentally friendly when compared to other conventional boiler models, especially if you opt for a condensing gas boiler to heat your home
• Lifespan of 10-20 years, will little regular maintenance required
• Wall-mounted gas boilers take up little space, often with lower installation costs than floor-standing gas boilers

Disadvantages of gas boilers

• For propane gas boilers, the price of propane is fairly high
• You’ll need to regularly replenish and safely store your propane supply
• Floor-standing gas boilers can be slightly trickier to install, at a slightly higher cost - work around that by opting for a space-saving, easy to install wall-mounted option!

Choosing the right gas boiler for your home: classic, low temperature or condensing?

As mentioned above, gas boilers can be wall-mounted or floor-standing and run on natural gas or propane. If you opt for a natural gas boiler, you’ll just need to connect your boiler up to the natural gas grid network. If you install a propane gas boiler in your home, you’ll need to safely connect it up to a propane storage tank - and make sure your propane supply is stocked up!

Aside from these different options, there are three main types of gas boilers you can choose from to heat your home: a classic gas boiler, a low temperature gas boiler or a condensing gas boiler.

Classic gas boilers

Classic gas boilers are the original gas boiler option - the first to exist. Nowadays, there are a variety of models that are far more energy efficient, cost efficient and environmentally friendly. Classic gas boilers are the cheapest option for heating your home and operate according to the three basic steps we looked at earlier in this piece.

Low temperature gas boilers

These gas boilers are very similar to their classic predecessors, with one key difference: low temperature gas boilers limit their low temperature to 40°C in order to increase their energy efficiency levels. If you want to install a low temperature gas boiler in your home, you’ll first need to check that your central heating system (radiators or underfloor) is compatible with this type of gas boiler model.

Condensing gas boilers

Condensing gas boilers are the newest and most energy efficient gas boilers out there. These boilers operate using the fourth, additional step we described above, collecting the latent thermal energy from the fumes produced in the conventional combustion process. Utilising this additional energy to heat your home makes condensing gas boilers a more energy efficient and environmentally friendly option for your home. What’s more, you should see a significant reduction in your home energy bill!

It’s important to note that classic and low temperature gas boilers are gradually being phased out in favour of condensing gas boilers, in order to better protect the environment.

Gas boilers: suction cup or flue system?

Whichever type of gas boiler you choose to install in your home, you’ll need to choose between a suction cup or flue system for evacuating the associated fumes and vapours.

Suction cup system

Formed of two horizontal concentric tubes, this system isolates your gas boiler so it can be installed in most homes.

Flue system

Classic flue pipes enable fumes and vapours to exit the home, with insulation to prevent excess boiler condensation.

Gas boilers: energy efficiency and price range

When it comes to energy efficiency levels, gas condensing boilers win hands down: a home heating system that uses a gas condensing boiler can achieve up to 110% efficiency, while classic boilers rarely exceed the 100% mark.

While condensing gas boilers are by far the most expensive outright purchase, the money they’ll help you save on your home heating bills ensures they’re a profitable investment in the long run. Plus, they’re far better for the environment.

There are multiple advantages to replacing an old, classic gas boiler with a condensing gas boiler: higher energy efficiency, better performance and reduced home heating bills. If you’re looking to save space, too, opt for a wall-mounted condensing gas boiler for easy, relatively inexpensive installation.