In the UK, where home heating that is efficient and good is crucial, gas boilers have traditionally been backbones to central heating systems. To heat cosy inner-city flats as well as rural houses, gas boilers are an established technology for delivering good and dependable hot water and heat. With growing interest in renewable heat technology, gas boilers continue to be widely used since they are convenient, efficient, and cheap.
This article explores what gas boilers are, how they work, the different types available, their benefits, and what to consider if you’re planning to install, replace, or upgrade your existing system.
1. What is a Gas Boiler?
A gas boiler is one of the equipment that utilizes natural gas to heat water which will be pumped around a few radiators or underfloor systems to try to heat the property. It also heats up water for showering and for taps.
Gas boilers burn mains gas in the majority of cases, but then where homes are not getting gas supplied, they will fire LPG (liquefied petroleum gas) stored in cylinders.
They comprise the majority of UK domestic heating, with most installations due to being efficient, available, and reliable.
2. Operation of Gas Boilers
Though the design varies, the general working is as below:
Ignition: Fuel is burned within the boiler through a burner.
Heat Transfer: The flame warms a metal item (heat exchanger), warming water.
Water Distribution: Hot water is pumped around a sealed pipe circuit to radiators or floor systems.
Domestic Hot Water Supply: Blended systems also include the operation of the boiler stand-by to provide demand for hot water for showers and taps.
Condensing gas boilers recover and recycle waste heat from the flue and are highly efficient.
3. Gas Boiler Types
Having the proper type of gas boiler is most crucial to efficiency and convenience. The three below are the most common ones installed in UK houses:
a. Combination Boilers (Combi Boilers)
Supply both hot water and central heating from a tidy single unit.
Instantaneous hot water – no storage container required.
Suits best in apartments or a house with a single bathroom.
Advantages: Efficient, faster hot water, space-efficient.
Cons: Could not support large family with high hot water usage.
b. System Boilers
Require external hot water cylinder but not cold storage tank.
Can supply multiple bathrooms simultaneously.
Pro: Most suitable for houses which have higher demand of hot water, faster hot water re-covery compared to conventional boilers.
Con: Takes more space than combi boiler.
c. Conventional Boilers (Regular or Heat-Only)
Utilize both an unvented cold-water storage cistern and a hot water cylinder.
Universal in older homes with conventional boiler installations.
Points: Ideal for large properties, two or more bathrooms, can be fitted into existing pipework.
Against: Takes up more space, takes longer to heat the water.
4. Gas Boilers Advantages
Although with greater popularity from other sources like heat pumps and solar thermal systems, gas boilers remain the most in demand because of the following benefits:
a. Low Cost Heating
Gas is typically cheaper than electricity or oil, and thus gas boilers are cost-wise when it comes to fuel.
b. Greater Efficiency
Condensing new gas boilers are more than 90% efficient, energy-efficient and lowering the cost of heating.
c. Instant Hot Water
Provide direct instantaneous hot water through combi boilers without tank storage to pre-heat in advance.
d. Slim Designs
There are designs that are slim enough to fit into cupboards or wall-mounts, ideal to be fitted in areas where space is limited.
e. Established Infrastructure
Infrastructure for supply and maintenance of gas is already available throughout the UK, favouring easier fitting as well as ease of repair.
f. Proven Technology
Gas boilers have been used for decades now, and technology is hence adequately tested, established, and well known to most heating engineers.
5. Boiler Energy Efficiency Ratings
The government of the UK makes sure that new boilers are condensing boilers, which re-route waste gases to extract more heat, in a more efficient manner.
While buying a gas boiler, consider the ErP (Energy-related Products) rating:
The best boilers are A-rated.
They save carbon emissions and fuel bills.
Smart thermostats and controls are typically installed on new boilers to achieve optimal performance.
6. Installation Requirements
Prior to selecting a gas boiler, take the following into consideration:
a. Heating Requirement
Take measurements of your house, bathrooms, and your daily hot water usage.
b. Boiler Location
Boilers can be installed in utility rooms, kitchens, or loft space. Take noise, accessibility, and ventilation into consideration.
c. Gas Supply
Ensure that your property is mains gas supplied. Otherwise, you may be required to have an LPG-compatible one installed.
d. Installer Qualification
Single fitting by Gas Safe registered engineers. This is a UK legislative requirement for gas appliances.
e. Warranty
New boilers are typically supplied with 5- to 10-year warranties. The longer the warranty, the better the build quality.
7. Servicing and Maintenance
Yearly servicing will provide maximum performance, prevent faults, and satisfy the conditions of the guarantee.
Benefits of Yearly Servicing:
Detects gas escapes or carbon monoxide danger.
Wastes less energy.
Prevents costly faults and repair fees.
Provides safety standard compliance.
Ensure a Gas Safe registered engineer performs the servicing and repairs at all times.
8. UK Gas Boiler Future
Gas boilers are still widely used today, but their long-term future is being undermined by climate change targets.
a. Hydrogen-Ready Boilers
Companies are producing hydrogen-ready boilers that can convert from natural gas to hydrogen the moment the fuel comes on sale in bulk.
b. Low-carbon alternatives
The government is promoting air source heat pumps and biomass installations as low-carbon alternatives, especially for new-builds.
c. Regulation changes
The UK will install new houses without gas boilers for sale by 2025, but the old houses may have them installed and replace later.
