The ideal boiler for your home is one of the most significant decisions you’ll have to make, especially with the rising energy costs and cost-of-living crisis. The right choice of heating system is the most impactful decision towards a warm home and a low energy bill. If you are replacing an old boiler or getting a new heating system installed, understanding the various types of boilers will help you make an informed decision, aiding you in picking the most suitable system that will warm your home for years to come!
The Three Main Types of Boilers
When it comes to home heating, three types of boiler systems dominate the British market: combination (combi) boilers, system boilers, and traditional or regular boilers. They each have their pros and cons, and are best suited to a different type of home and family requirements.
Combi Boilers: The UK’s Most Popular Choice
Combi boilers are the most common system in UK homes these days, with more than 54% of homes choosing this option. A combi boiler both heats and supplies hot water from one compact unit, making it an ideal space-saving system for homes.
How Combi Boilers Work
Combi boilers are fed directly from the mains water supply and heat water instantly on demand. When you switch on to a hot tap or shower, the boiler turns on and heats the water straight away through an internal heat exchanger. This provides you with unlimited hot water whenever you need it, without the need for an additional hot water storage tank.
Advantages of Combi Boilers:
- Space-saving: No hot water tank or cold water storage tank required
- Energy efficient: Only heats the water when required, minimizing wastage
- Instant hot water: Not having to wait for the water to get hot in a tank
- Easy installation: Single-unit installation is faster and easier
- Cost-effective: Typically the lowest installation cost option
Combi Boiler Disadvantages:
- Limited simultaneous usage: Water pressure lowers when too many taps are opened at the same time
- Not ideal for large homes
- Mains pressure reliant: Performance undermined by periods of low water pressure
Combi boilers are best suited for small to medium homes that have 10 or fewer radiators, or flats and apartments where space is limited.
System Boilers:
System boilers provide a compromise between combi and traditional boilers. They use an independent hot water cylinder to hold warm water but lack a loft cold water tank. They are hence less bulky than traditional systems without sacrificing good hot water capacity.
System boilers warm water stored in a hot water cylinder, usually in an airing cupboard. Large components such as pumps and valves are incorporated into the boiler unit, which simplifies the installation compared to traditional systems. The stored warm water can be fed to various outlets at once without dropping pressure.
Benefits of System Boilers:
- Multiple outlets: Can serve multiple taps at once
- Ideal for larger houses
- Quicker installation: Comprehensively built components minimize installation complexity
- Backup alternatives: Can include immersion heaters for emergency heating
- Constant pressure: Less prone to mains water pressure fluctuations
Disadvantages of System Boilers:
- Space needs: Require space for hot water cylinder
- Heat loss: Energy lost through cylinder heat dissipation
- Greater initial cost: More costly to install than combi boilers
Best suiting larger houses with high hot water demand.
Traditional Boilers: Uncompromising Reliability
Traditional boilers, or heat-only or regular boilers, are old heating systems which many older British homes still use today. Traditional boilers need both a cold water storage tank and a hot water cylinder, which are usually fitted in the loft space.
Traditional boilers pull water from a loft-stored cold water tank, heat the water in the boiler, and store hot water in a cylinder. The hot water is distributed through radiators and taps around the property. The system uses gravity and trapped pressure from the water instead of mains pressure.
Traditional Boilers Benefits:
- Great for big houses: Can easily cope with high hot water demand levels
- Low mains pressure compatible with the ability to operate regardless of mains water pressure
- Simultaneous multiple outlets: Able to supply multiple bathrooms without pressure reduction
- Friendly to older houses: Generally the best substitute for original traditional systems
- Backup hot water capability: Able to fit immersion heaters
Drawbacks of Traditional Boilers:
- Space required: Occupies space for hot water cylinder and cold water tank
- Installation complexity: More parts makes for a more complex installation
- High installation cost: Most costly to install
- Heat loss: Energy lost during from tank
Traditional boilers are best suited for large homes with installed conventional systems that may suffer from a low mains water pressure. Convenient for homes with extremely high hot water usage.
Boiler Systems by Fuel Type
In addition to their operation differences, different boiler types are also categorized according to fuel type. Knowing the alternatives allows you to select the most appropriate and cost-efficient heating solution for your house.
Gas Boiler Types:
Natural gas boilers are the most popular type of heating in the UK, utilized by about 85% of homes connected to the gas grid. They have high efficiency, with 90-99% efficiency factors being characteristic of well-maintained models. There are multiple advantages of gas boilers including them being cost-effective, as natural gas is often less expensive than electricity or oil. They are also very efficient and are considered reliable because of the reliable supply via the gas network. It also offers fast heating and is good for the environmental impact as it is considered cleaner than oil or coal.
For homes that are not connected to the mains gas supply, LPG (Liquefied Petroleum Gas) boilers are a convenient solution. They are similar in nature to natural gas boilers but operate from stored LPG rather than the mains supply.
Oil Boiler Types:
Oil boilers are mainly found in rural locations where there is no gas supply. Recently installed oil boilers can be up to 98% efficient, thus they are very efficient heating systems.
Types of Oil Boilers:
- Oil combi boilers: Supply hot water and heating from one unit
- Oil system boilers: Use individual hot water cylinders
- Oil heat-only boilers: Conventional systems with cold water tanks and hot water cylinders
Advantages of Oil Boilers:
- Rural home friendly: Suitable for houses without gas supply
- Heating reliability: Durable when the weather gets cold
- Future-proofing: Can be reconfigured to utilize HVO biofuel
Electric Boilers
Electric boilers are gaining popularity, especially for smaller homes that do not have a gas supply. They are very efficient and are more eco-friendly as the grid becomes more advanced.
Advantages of Electric Boilers include them being100% efficient, as no heat lost down flues, as well as their compact size, as they are smaller than oil or gas boilers. They also offer quiet operation with no sound of combustion, and come with an easy installation as they have no requirement for flue. The low maintenance needs because of less moving parts compared to gas boilers is another added benefit!
Considerations:
- Highest running costs: Gas is cheaper than electricity
- Restricted to small properties: Suitable for houses with smaller heating requirements
Ready to upgrade your boiler for free? Fill in our eligibility form and get the latest A-rated condensing boiler installed completely for free under the government’s ECO4 scheme.
Condensing vs Non-Condensing Boilers: What's the Difference?
Condensing Boilers: The New Benchmark
Since 2005, it has been a legal requirement for new gas boilers installed in the UK to be condensing boilers. This has been implemented with the goal of increasing energy efficiency and reducing carbon emissions.
Condensing boilers use advanced heat exchanger technology to reclaim and reuse heat from waste gases that would otherwise be lost down the flue. When these hot gases chill, they condense back into liquid form, releasing excess heat energy which is used to heat your home.
Key Advantages:
- Higher efficiency: 99% efficient compared with 78% for non-condensing models
- Reduced running costs: Up to £500 per year off gas bills
- Environmental advantages: Significantly lower carbon emissions
- New technology: Often equipped with smart controls and high-level diagnostics
Identifying a condensing boiler:
- Plastic flue: Condensing boilers will often have white plastic flues
- Condensate drain: Short plastic pipe to a drain
- Installation date: Any boiler installed after 2005 is likely to be condensing
Non-Condensing Boilers:
Non-condensing boilers are the old technology which was standard prior to 2005. These appliances lose a lot of heat down the flue and are much less efficient compared to modern equivalents.
Features:
- Lower efficiency: Usually 60-80% efficient
- Higher operating costs: Lose more energy through heat loss
- Metal flues: Boiler flue types differ as these often have metal flue pipes.
- No condensate drain: Don’t give off condensate water
Important Note: Installing non-condensing boilers in the UK is illegal now except if you are specially exempted. If you already own an old non-condensing boiler, you can save hundreds of pounds each year by installing a condensing boiler. Fill in our eligibility form or contact us to check if you qualify for a free boiler upgrade under the ECO4 scheme.
Home Energy Guide
Home Energy Guide realizes that selecting the perfect boiler is just the first step towards developing an energy-efficient home. Our expertise goes beyond boiler installation to complete energy solutions meant to heat your home more comfortably and ease the burden off the environment. We offer a professional assessment to identify the most appropriate type of boiler to suit your individual needs. From small combi boilers for your city center flat right through to cost-effective system boilers for your home, we offer personalized advice.
We offer exclusive experience in helping eligible homeowners access government ECO4 funding to replace boilers. The scheme can provide fully funded boiler replacements to eligible households, potentially saving thousands of pounds on your heating installation.
