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The Beating Heart of your Home

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No-one likes a cold shower (though sometimes people need one!) and everyone appreciates coming back to a warm home in the depths of winter. Your boiler really is the beating heart of your home, ensuring everything works as it is supposed to... from your kids getting clean to making sure your radiators are running.

So, let’s take a tour through the world of boilers. If you have any further questions or need someone to make sure your home’s heart keeps on humming... just get in touch.

So. let’s start with the basics. Boilers are what give you the hot water in your house, whether this be used in taps, showers or the radiators of your central heating system. The type of boiler you use (or choose) is influenced by three main factors:

1. Fuel Source: What power sources are you connected to? Gas, electricity, solid fuel...

2. Usage: How large is the property and how many people could be using hot water at one time) and,

3. Space: Where is your boiler going to be and how much spare space do you have?

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Who has the Power?

Let’s get the fuel source sorted first. The vast majority of new boilers fitted are gas-powered. Whilst we admire you wanderers who have gone ‘off grid’ (literally), in London we are thankfully mostly plugged into the gas networks. Although gas boilers are slightly less efficient than electric boilers, this is more than made up for by the fact that gas is a fraction of electricity costs. Assuming normal usage, we would propose that gas boilers are around 30% cheaper to run than electric.

A Tale of 3 Boilers

There are 3 main types of gas boiler: regular, combi and system.


The regular (AKA ‘Conventional’) boiler system is made up of a number of parts. These include a boiler (surprise!), a hot water cylinder, a cold water storage cistern plus a feed and expansion cistern. And if it sounds like this takes up a lot of space. Well, it does. Although being called regular, these are actually being installed less and less and are normally found in older and larger homes.

If you’ve renovated a house in the last few years, or been rummaging around in a loft and wondered what the big tanks are - these are part of your boiler system. The boiler system is fed by two tanks: one is the cold water storage tank, which draws cold water from the mains supply. The other is the feed and expansion tank, which feeds the boiler system and manages any water that expands in the system after being heated.

Given all the above, why would anyone get a regular boiler system? Well, there are a few reasons. The first is that you can have multiple taps and showers running without losing pressure. The second is that they are often easier to integrate with existing systems. Last, they allow for a backup plan since you can have an immersion heater in the water cylinder to provide an alternative heating source.

The downsides of this type of installation are the space it takes up. And if it sounds complicated to install? It is. Also, unlike other boilers you won’t have instant access to hot water and having hot water is kind of the point.


Combi boilers are the popular powerhouses of the heating world. Accounting for more than half of the boiler installations that occur, these boilers are so named because they provide a ‘combination’ of hot water and central heating (and then someone felt ‘combination’ was too long a word). Small and very efficient - normally over 90% - combi boilers work by heating the water directly from your mains supply, so there is no need for a water tank or storage cylinder. Since water is only heated when it is used (and not heated and then stored), they are also the most cost-effective option in many cases.

Combi boilers sound amazing. Why doesn’t everyone use them? Although they are normally cheaper to install, combi boilers are not always appropriate. First, they require a good level of mains pressure since this is what is used to send hot water where it is needed. Second, you can’t run more than one shower, bath or hot tap at any time. Last, there is no backup possible. If your boiler breaks, you can say goodbye to hot water.


A system boiler can almost be thought of as a ‘combi combi conventional’. Like a combi boiler, it takes its’ water directly from the mains (rather than having a feed cylinder) but like a regular boiler, it keeps the heated water in a storage cylinder. It is also smaller than a regular boiler in that the expansion vessel and pressure release valve are normally located within the boiler itself.

The system boiler sounds like a happy medium. Is that right? Well, to a certain extent, yes that’s true. Unless your property is small and therefore only needs a combi boiler, the system boiler would generally be our proposed solution. They are fairly easy to install and you can use multiple taps at once. Plus, they don’t require the feed tank which means you can have your loft space back (spare bedroom anyone?). They do of course still require a storage cylinder which you must ensure is large enough to cover your daily needs.

Who can put a price on a warm home?

Your Homyze can. Here are some installation cost guidelines.

Boilers typically have a lifespan of 10 - 15 years. Whilst it is unfortunate that you may need to replace a boiler, on the plus side they are now much more efficient (normally around 90% compared to around 50% for older boilers) so that your running costs should be considerably lower. They are also much better for the environment.

Also, please note that gas appliances such as your boiler should really be inspected annually. Your Homyze are happy to do this for you - just get in touch with us to arrange.

So, obviously the cost of a boiler replacement depends on the work involved and the boiler selected, but here is some idea of the amounts involved. Your Homyze are happy to give you a quote and will come to visit you to ensure we offer the appropriate solution.

There are usually three components to the cost of a boiler replacement: 1. the boiler 2. installation, and 3. a powerflush. Boiler costs are likely to vary the most, and these are slept out further below, whilst a powerflush is normally £400 - 500 and installation is normally £600 - 800. Both these costs are dependent on the work involved (e.g. moving a boiler’s location will add considerably to this amount). You may also need to pay for thermostatic radiator valves and a new magnetic filter to ensure your boiler continues to function smoothly.

Which brings us to the boiler costs. Boilers vary considerably in cost depending on the type of boiler, the brand and its capacity.

For reference, combi boilers are available in three sizes: 24 - 27kW, 28 - 34kW and 35 - 42kW. For a small house or a flat with up to 10 average size radiators, the 24 - 27kW condensing boiler replacement should suit you fine. The 28 - 34kW radiator would work up to a 3-4 bed house with up to 15 radiators and the 35 - 42kW version would be for anything larger.

Which brings us to brand. Typical costs across the three most frequently used brands are as follows:

Glow Worm£600 - £1,400
Vaillant£650 - £1,500
Worcester£800 - £2,000

These are for the boilers only (without installation or powerflushing). As you can see, there is quite a range, but all should come with a warranty (normally 5 years).

Last, please ensure you use a Gas Safe Registered heating engineer to inspect, service or replace your boiler. As we have said, the boiler is the beating heart of the home and you wouldn’t let just anyone operate.

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