Combi vs system boiler for a Hexham home
If you are replacing your boiler, one of the first decisions is whether to choose a combi boiler or a system boiler. Both are common in homes around Hexham, and both can be the right answer. The best choice depends on how your household uses hot water, how many bathrooms you have and what your mains water supply can deliver.
How a combi boiler works
A combination (combi) boiler heats water for your taps instantly, straight from the mains, whenever you turn on a hot tap. It also heats your radiators. There is no hot water cylinder and no water tanks in the loft.
Strengths:
- Saves space – no cylinder or loft tanks.
- Hot water on demand, so you never run out.
- Often simpler and quicker to install as a like-for-like swap.
Limitations:
- Hot water flow depends on your mains pressure and flow rate.
- Struggles when more than one hot tap or shower is used at the same time.
- Not ideal for larger homes with several bathrooms.
How a system boiler works
A system boiler heats your radiators and also heats a separate hot water cylinder, which stores hot water ready to use. Most of the system’s components are built into the boiler, so there are usually no tanks in the loft. Many system boilers are paired with an unvented cylinder fed from the mains, which gives strong pressure at every tap.
Strengths:
- Can supply several showers and taps at once.
- Good for larger homes and busy households.
- Works well with solar thermal or other hot water sources.
Limitations:
- Needs space for a cylinder.
- Hot water can run out if the cylinder is too small for your household.
- Unvented cylinders need specialist installation and yearly checks.
What matters most in a Hexham home
Number of bathrooms
A one-bathroom terrace or flat usually suits a combi well. Homes with two or more bathrooms – common in larger houses around Corbridge, Riding Mill and Stocksfield – often do better with a system boiler and cylinder.
Mains water pressure and flow
A combi can only deliver hot water as fast as your mains supply allows. Some homes, especially on higher ground or at the end of long supply pipes, have lower flow. We test mains pressure and flow before recommending a combi.
Space
If you are short of space, removing a cylinder and loft tanks can free up a useful cupboard. If you have the space and need the hot water capacity, a cylinder may be worth keeping.
Older stone properties
Many older homes in and around Hexham have existing cylinders and tanks, long pipe runs and extensions added over time. Converting to a combi can work well, but it is worth checking that the hot water will reach distant taps quickly enough and that the boiler can cope with the house’s heating demand.
A quick guide
| Your home | Often suits |
|---|---|
| One bathroom, 1–3 people, good mains flow | Combi |
| Short of cupboard space | Combi |
| Two or more bathrooms | System boiler + cylinder |
| Several people showering at the same time | System boiler + cylinder |
| Low mains water pressure or flow | System boiler (or other options) |
This is only a starting point – every home is different.
Getting it right
The most important thing is to choose a boiler based on your home and your hot water use, not just on what was there before. We assess this as part of every boiler installation quote and explain the options clearly. If you would like advice, request a quote and tell us about your home.
Frequently asked questions
Is a combi cheaper to install?
A like-for-like combi swap is often simpler than other options, but the cost depends on your existing system and what needs changing.
Can a combi run two showers at once?
Some larger combis can manage two showers if mains pressure and flow are good, but performance drops. Homes that regularly need two showers at once often suit a system boiler with a cylinder.
Do I need a hot water cylinder with a system boiler?
Yes. A system boiler heats a separate hot water cylinder, which stores hot water ready to use.
