What type of boiler do I have?
Written by Stephen Day
Gas Safe Engineer
Updated:
5 min read
Not sure which type of boiler you have? Learn how to identify a combi, system or regular boiler with a few simple checks around your home.
In this article
Key takeaways
- Cylinders and loft tanks help identify your boiler type.
- Check the boiler model or manual to confirm.
- Switching to a combi depends on water supply and household demand.
Knowing your boiler type helps when arranging repairs or replacing your boiler. Most homes with gas central heating have a combi, system or regular boiler.
The easiest starting point is to check whether you have a separate hot water cylinder and any water tanks serving the system.
Which type of boiler do I have?
Boiler type | Separate hot water cylinder? | Water tanks in the loft? |
|---|---|---|
Combi | Usually no | Not needed |
System | Usually yes | Not normally needed |
Regular | Usually yes | Common in traditional setups |
Quick tip: These are typical arrangements. Your boiler's model name and manufacturer's manual are the best way to confirm its type.
Combi boilers
A combi boiler provides central heating and heats water for your taps from one compact unit. It normally needs no separate hot water cylinder, making it useful where storage space is limited.
Do I have a combi boiler?
Look for these common signs:
No separate hot water cylinder in an airing cupboard or elsewhere.
No water tanks needed for the boiler system.
Water heats on demand when you turn on a hot tap.
Main benefit: Saves space and provides hot water without waiting for a cylinder to reheat.
Worth considering: Running several taps or showers together can reduce flow. Performance depends on the boiler's output and your mains water supply.
System boilers
Look for these common signs:
A separate hot water cylinder, often in an airing cupboard.
No loft tanks normally needed for the system.
Stored hot water, which needs reheating after it has been used.
Main benefit: A suitably sized cylinder can serve homes where several people need hot water at similar times.
Worth considering: You need space for the cylinder, and the available hot water depends on its capacity and reheating time.
Good to know: A cylinder usually refills as water is used. If the hot water runs out, the wait is mainly for the replacement water to heat up.
Regular boilers
Regular boilers are also called conventional, traditional or heat-only boilers. They usually work with a separate hot water cylinder and, in traditional installations, water tanks in the loft.
Do I have a regular boiler?
Look for these common signs:
A separate hot water cylinder, often in an airing cupboard.
Water tanks in the loft serving the hot water or heating system.
An external heating pump, separate from the boiler.
Main benefit: Can be a practical replacement for a home with an existing traditional heating system.
Worth considering: The cylinder and tanks take up space. Some regular boilers use sealed systems without loft tanks, so check the boiler model to confirm.
Other boiler types you might have
Not every home uses mains gas. Your boiler may use a different fuel, or you may have an older setup.
LPG boilers: Use liquefied petroleum gas supplied from an external tank or cylinders. LPG boilers can be combi, system or regular models.
Oil boilers: Burn heating oil stored in an external tank. Often found in homes without a mains gas connection.
Electric boilers: Use electricity to heat water for your central heating. They don't burn fuel or need a combustion flue.
Biomass boilers: Burn wood pellets, chips or logs. Look for a fuel store or hopper near the boiler.
Back boilers: Sit behind a fireplace or stove and provide heat for the heating system, often alongside a separate hot water cylinder.
Good to know: "Combi", "system" and "regular" describe the boiler's setup. "Gas", "LPG", "oil" and "electric" describe its energy source. A boiler can belong to both categories - for example, an LPG combi boiler.
Still unsure which boiler you have?
Find the make and model on the outside of the boiler or in its paperwork.
Check the manufacturer's manual for the boiler type.
Contact iHeat with the model name and photos of any visible cylinder or tanks.
Get in touch with our team for help identifying your setup.
Can my conventional boiler be converted to a combi bioler?
Yes, many homes can switch from a regular boiler to a combi. Whether it is suitable depends on your water supply, hot water demand and existing heating system.
Before recommending a conversion, your installer will check:
Mains water pressure and flow: Whether the supply can support the proposed boiler.
Hot water demand: How many taps and showers you use at the same time.
Existing pipework and radiators: Whether they are suitable for the new setup.
Cylinder, tanks and shower pumps: Which components need removing or changing.
Before you switch: A combi can free up storage space, but it is not automatically the best choice for every home. Ask your installer to assess your household's hot water needs.
Frequently Asked Questions
Is a condensing boiler the same as a combi boiler?
No. "Condensing" describes how a boiler recovers heat from waste gases. "Combi" describes how it provides heating and hot water. Combi, system and regular boilers can all use condensing technology.
Are regular, conventional and heat-only boilers the same?
Yes. These names generally describe the same boiler type, which provides central heating and usually works with a separate hot water cylinder.
Does a hot water cylinder mean I have a system boiler?
Not necessarily. Both system and regular boilers can use a hot water cylinder. Check the boiler’s model name and manual to confirm which type you have.
Can a regular boiler work without a loft tank?
Yes. Some regular boilers are installed on sealed systems without loft tanks. The absence of a tank alone does not confirm that you have a system or combi boiler.
Where can I find my boiler’s make and model?
Look for the name on the front of the boiler, an accessible label underneath, or your boiler manual and installation paperwork. The location varies by manufacturer. You shouldn’t need to remove the boiler casing.
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