Have you ever been looking forward to a nice warm shower, only to find there isn’t enough hot water? Maybe there’s enough water for your shower, but not enough to put the heating on? Sound familiar? Well, it’s likely you’re still using a conventional ‘tank and cylinder‘ boiler.
Nobody wants to get out of the shower and step into a cold room, do they? A combi boiler (combination) solves both problems in one compact unit. Not only supplying on-demand hot water, but also providing central heating without a separate tank.
But – what is a combi boiler? Is a combi boiler cheaper to run? And exactly how does a combi boiler work?
New combi boilers eliminate both of these problems for you. You will, of course, have questions – what is a combi boiler? How does a combi boiler work? Is a combi boiler cheaper to run?
Not to worry. In this blog, we’ll tell you simply how a combi boiler works and the
Whether you’re in Maidstone, Ashford, or anywhere else in Kent, this situation can really ruin your morning.
New combi boilers eliminate both of these problems for you straight away, and in this blog, we’ll tell you why. What is a combi boiler, and how does it work? Read on to find out more.
What is a combi boiler?
A combi boiler – what is it? Well, in short, it provides you with heat and hot water from a single source.
A conventional boiler, whilst it may look the same on your wall, requires a cold water storage tank, often found in your loft, and a hot water storage cylinder, usually found in an upstairs storage or airing cupboard.
A combi boiler, therefore, takes up much less space than a conventional boiler, and you don’t have to worry about the hot water tank running out just when you need it the most!
What is a combi boiler? In short, it’s a space-saving, multi-tasking heat and hot water provider for your home. It’s also far more efficient than an older boiler, so it should save you some money in the long term.
Combi boilers are also more reliable and often quieter, with more features that give you more control.
As well as natural gas, you’ll also find oil combi boilers and electric boilers.
How does a combi boiler work?
There are a number of different options when it comes to supplying hot water and heating in your home. As we mentioned, we’re often asked, “What is a combi boiler?” or “How does a combi boiler work?”
A combi boiler, or combination boiler, is just that. It combines the heating of your water and central heating capabilities in one place. When you turn on a hot tap in your home, your combi boiler will fire up instantly and heat the water that supplies your tap. When you turn the tap off, your combi boiler effectively goes back into temporary sleep mode until it’s needed again.
What about heating? When your thermostat drops below its set temperature, it sends a message to the combi boiler, which will spring into action and heat your home as required. Once the optimum temperature setting is reached, the boiler will receive another signal telling it to rest easy, warmth is restored. This scenario will be repeated as and when necessary in line with your thermostat settings.
As an alternative to letting your thermostat do its thing, combi boilers have a 24-hour timer that you can set so that your home is heated for certain hours of the day. Or, like many people these days, you can go one step further and control your heating and hot water via smart controls.
Wireless thermostats can be moved from room to room and can even be controlled by Alexa, Google or via an app on your phone, so you can ensure the heating is on before you get home. No more coming home to a cold house!
There are many possibilities, but we can help you choose the right method for your home and lifestyle.
Learn more in our guide to smart thermostats and how they work.
Why choose a combi boiler?
Combi boilers are brilliant for small to medium homes with one or two bathrooms.
- Space saving: The typical combi boiler is small enough to fit inside a standard-sized kitchen cupboard, and because everything is contained in one unit, you don’t need to find room for a hot water cylinder or storage tank.
- Highly efficient: Combi boilers use condensing technology, which makes them very efficient. In short, it means more of the fuel you pay for is turned into usable energy to heat your home.
- Hot water on demand: With a combi boiler you get hot water on demand. So unlike with a conventional boiler, you don’t need to wait for the water to heat up or the tank to refill before you can have a bath.
- Long lifespan: Gas combi boilers have a long lifespan. With annual servicing and proper maintenance, you can expect your boiler to last between 10 and 15 years. This makes them a smart choice for anyone searching ‘how to use a combi boiler for the long term’.
- Cost-effective: Combi boilers often work out cheaper to install. As everything is contained inside one unit, there is less pipework and equipment to fit, and fewer things that can go wrong!
Capacity and space are the trade-offs here. Combi boilers take up much less space than a system or regular boiler, but they are also less powerful, making them unsuitable for large homes with two or more bathrooms and a high demand for hot water.
How much is a new combi boiler?
A new combi boiler will cost somewhere in the region of £1000 to £3000. Combi boiler prices vary and depend on the make and model, among other things.
There are many different brands to choose from, some better than others, and most brands will have a range of boilers or a budget, mid-range, and premium option, each providing you with a different specification to suit the needs of every home.
Your qualified installer will be able to help and advise on which is the best option for your needs. Some of the factors that might affect combi boiler prices are:
- make and model
- warranty period – usually from 2 years to 12 years
- what you are replacing and whether extra components might be needed
- location of the boiler in your home
- smart controls
- the demand put on the boiler to meet your requirements
What is the best combi boiler?
This is a question that depends on your specific needs. You have to take into consideration how big your home is, how much hot water you use, what your budget is, etc.
Worcester 4000 Vs Worcester 8000 – The current debate in 2025.
Generally speaking, the Worcester Bosch Greenstar 8000 combi boiler is generally a more powerful and feature-rich option than that of the 4000. It’s more suitable for larger homes and those with higher hot water demands.
However, just because on paper the 8000 is better, the Worcester Bosch Greenstar 4000 is still efficient for smaller and medium-sized homes. It’s worth a lot of consideration, because you want the best boiler for your situation, not just the one that is better on paper.
Consider your needs, the size of your house, etc. That way, you’ll have an easier choice on what boiler is best for you.
Here’s a little table breaking down all of that information.
| Feature | Greenstar 4000 30 kW | Greenstar 8000 Style 35 kW |
| Hot‑water flow rate | 12.3 ℓ/min | 14.3 ℓ/min |
| Display | Simple LED | Full‑colour TFT & touch controls |
| Ideal homes | 2‑4 beds, 1 bathroom | 4‑5 beds, 2 bathrooms |
Is a combi boiler cheaper to run?
How much it costs you to run your boiler depends on the size of your house, how well insulated it is, and how often you use it. Of course, it goes without saying that the more you use your boiler, the more you’ll pay in fuel.
Overall, combi boilers are more cost-effective to run than conventional boilers. This is because with a combi boiler, you’re only paying to heat the water you use rather than a whole tank of water.
Whether you choose a conventional or a combi boiler, there’s no doubt that new systems are much cheaper to run than their older and less efficient counterparts.
In fact, the Energy Saving Trust estimates that you can save hundreds of pounds on your fuel bill by replacing your old boiler with a new, A-rated boiler. Going from a G-rated boiler to an A-rated condensing boiler could save you up to £445 per year (based on a mid-terraced house in England, Wales, or Scotland).
Modern combi boilers like the Worcester 4000 and Worcester 8000 are designed to run at 90% more efficiency than old boilers, saving you much more than your older, current boiler.
Why choose Arton Plumbing and Heating?
Based in Maidstone, Kent, we’re a local family-run business providing plumbing and heating services to the surrounding areas. With over 35 years of experience, Arton Plumbing and Heating is proud to be a Worcester Bosch accredited installer.
Our friendly Gas Safe registered engineers are qualified to repair and service your existing boiler or install a new combi boiler with a fantastic warranty period of up to 12 years on some models.
We also offer 0% boiler finance packages to help spread the cost of your new boiler.
We make the whole process as easy as possible for our clients, and we aim to ensure there is minimal disruption during our work. We pride ourselves on looking after your home as though it were our own, and the quality of our workmanship is second to none.
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