What Type Of Boiler Do I Have? A Comprehensive Guide

Last Updated on February 11, 2025

Knowing the type of boiler in your home is crucial, especially when considering repairs, replacements, or upgrades. Boilers come in various types, and each is suited to specific needs and home configurations.

The three primary types of boilers in the UK are combi, system, and regular (or conventional) boilers. Each of these can run on different fuel sources such as gas, electricity, oil, biomass, or LPG.

This article will guide you through the different boiler types and provide expert insights on how to identify which one you have, ensuring you’re well-informed when considering repairs or upgrades.

What Type Of Boiler Do You Have? Signs to Look Out For

Knowing about the different types of boilers will not only inform you whether you have the right type but can also help answer the question “What size boiler do I need?” if your current type is not meeting your hot water demands.

Below we’ll discuss the different boiler types as well as the different fuel sources that power boilers and heat up water.

Combi boilers

A combi boiler (combination boiler) is a fantastic choice for smaller homes due to its efficiency and compact size. These multitaskers take care of all your hot water and heating needs.

Thanks to their ability to save space, combi systems are a favourite in UK homes, particularly for new installations.

Unlike traditional systems, combi boilers draw water directly from the mains. This means they don’t need a hot water storage cylinder or a cold water tank, saving precious space in your home.

How to identify a combi boiler

Check for five copper pipes emerging from the bottom of the boiler – this is a telltale sign. You’ll also notice that there is no external pump or hot and cold water cylinders. A combi boiler is usually small, compact, and is always connected to the water mains. 

System boilers

System boilers offer the best of both worlds: the efficiency and compactness of a combi boiler with the capacity to handle higher demands like a regular boiler.

A system boiler doesn’t need a cold water storage tank because most of its heating components are built into the system, making it a great choice for modern homes.

These boilers heat water using a heat exchanger and store it in a hot water cylinder, ready for use. The system distributes hot water to radiators for heating and taps as needed, ensuring a consistent supply.

How to identify a system boiler

You will notice a hot water cylinder in the airing cupboard, and the unit will typically have three pipes: one for the central heating system, one for the mains water supply, and one for the hot water cylinder. The system boiler unit itself will be slightly larger than a combi boiler but still compact.

Regular boilers

Regular boilers, also known as heat-only or conventional boilers, are a traditional heating solution in the UK, particularly for large homes.

These boilers, paired with a cold water tank and a hot water cylinder, are large enough to ensure there’s always enough hot water for everyone and the central heating system.

Water is supplied to the boiler from a cold water storage tank (usually in the loft) and is then heated and stored in a separate hot water tank (usually in your airing cupboard).

How to identify a regular boiler

To spot a conventional boiler, check for two copper pipes at the top and one at the bottom of the boiler. The main giveaway is the presence of both a hot water cylinder and a cold water storage tank. A regular boiler also has an external pump.

Gas boilers

Gas boilers are by far the most common type in UK homes. They rely on natural gas, which is piped directly into the home, making them highly convenient. Modern gas boilers are typically condensing boilers, which use condensing technology to recover heat from the flue gases and increase efficiency.

The boilers work by burning gas to heat water, which is then circulated through the home. 

How to identify a gas boiler

You’ll notice a gas supply line connected to your boiler. There will also be an exhaust flue on the outside of your house, through which the boiler vents byproducts from the combustion process.

Electric boilers

It will come as no surprise that electric boilers use electricity to heat water. This is a much more environmentally friendly heating solution when compared to fossil-fuel-burning boilers. 

Electric boilers are very efficient, as almost all the electricity used is converted to heat. Because there are no requirements for a gas supply or flue, this type of boiler is often more compact. 

If you want to know more about electric boilers vs gas boilers, read our comprehensive guide.

How to identify an electric boiler

Electric boilers are very silent in operation compared to their gas or oil counterparts. They will lack both a flue exhaust and a fuel supply line, and instead, there will be an electrical connection that powers the system’s heating elements.

Oil boilers

Oil boilers are less modern than electric and gas boilers. These boilers use oil as fuel, making them a great alternative solution for off-grid homes. 

Oil boilers tend to have a high heat output, so they’re great for larger homes or very cold climates.

How to identify an oil boiler

Look for an external oil tank connected to the boiler with a fuel line. If you notice a distinct oil smell around the boiler, it’s likely an oil-powered system. 

Biomass boilers

Biomass boilers use organic materials (such as wood pellets, logs, or chips) to generate heat. These boilers are considered sustainable and eco-friendly, making them an excellent choice for homeowners interested in renewable energy solutions.

How to identify a biomass boiler

Biomass boilers are generally larger than other boiler types, and you’ll notice a large chamber for burning fuel. You may also see visible smoke or steam emanating from the flue when the boiler is in use.

LPG boilers

Liquefied petroleum gas (LPG) boilers use LPG as the fuel to heat water. These boilers are often found in homes not connected to the national grid. 

They’re as efficient as gas boilers and produce less emissions than an oil boiler. 

How to identify LPG boilers

You can identify this type of boiler by an LPG tank, which is either above or below ground, but always outside of the home. There will also be a fuel supply line connected to the LPG boiler and an exhaust flue. 

Considering a Boiler Upgrade? Here’s What You Need to Know

Considering a switch to a more efficient boiler system? Converting your existing regular boiler can be a smart move towards better efficiency and energy savings.

Many older boilers, particularly those with separate water tanks, can be upgraded to newer systems, like combi boilers or system boilers. These modern boilers are more energy efficient and can help save on electricity bills and reduce your home’s carbon footprint.

Upgrades can be as simple as adding advanced controls, like a smart thermostat, for better heat management or as comprehensive as replacing your boiler with a more efficient model.

Make sure you read our guide on the best smart thermostats if you’re considering one.

If you’re thinking about a boiler conversion or upgrade, it’s important to weigh your home’s needs and the benefits of new, efficient systems. Eco Happy is here to guide you if you have any boiler-related or upgrading queries.

Get Your Free Boiler Quote Today – Simple, Fast, and Tailored to You!

Ready to upgrade your boiler? Eco Happy makes it easy! Simply answer a few quick questions, and we’ll provide a tailored quote that suits your budget and home’s needs.

Don’t wait – get in touch with us today and take the first step toward a more efficient, cost-effective heating solution!

FAQs

How often should I service my boiler?

No matter whether you have a combi, system, or regular boiler, you should service your boiler annually. Regular servicing ensures it operates efficiently, identifies water or gas leaks, and maintains optimal performance.

Can I switch my boiler fuel type?

The only way to switch your boiler fuel type is to install a completely new boiler. For example, if you have an electric combi boiler, you’ll not be able to change the same boiler to work with gas – you’ll have to get a new gas combi boiler. 

What should I do if I can’t identify my boiler type?

Your boiler’s manual should provide you with information on the type of boiler you have. If you’ve lost the manual, you can always consult your boiler brand’s website or contact their customer service for assistance. Lastly, you can call out a heating engineer and have them come asses what type of boiler you have. 

Conclusion

Thanks to this handy guide, you will know what type of boiler you have!

Remember, knowing your boiler type is practical. It helps when you need a repair, want to purchase a new boiler, or just want efficient heating in your home.

If you have questions or need further advice, reach out to Eco Happy – we have all the eco-friendly boiler options you could want!