Whether you’re replacing an old boiler or fitting a complete new system, your boiler is a real investment in your home. But it’s very important to make sure you get the right one. Go overboard and you could end up spending much more than you need to. But try to economise too much and you could end up with a boiler that can’t cope with the demands you put on it. We’ll have a look at the types of boiler and show how they differ.

How much does a new boiler cost?

There’s no simple answer to this question, because there are several kinds of boiler, and each of those comes with different capabilities.

If you’re upgrading to a different system or installing a boiler where there wasn’t one before, you’ll also need to take the costs of installing all the pipework, cylinders, electronics, thermostats and radiators.

If you’ve got a system already installed but just need a new boiler, it can be relatively cheap to have it replaced.

So as a ball-park estimate, the price of a “new boiler” is typically in the £700 to £5000 range. £700 would represent a simple replacement of a small combi boiler in a flat. £5000 would be installing a new central heating system in a two-bathroom home, installing cylinders and relocating the boiler to another floor.

These are typical prices; in some circumstances an actual price could be outside this range, above or below.

What do I need to know?

With such a large range of possible prices, it’s important to ask yourself some simple questions:

  • Do I need to upgrade the system or does the current system work well?
  • Do I need extra radiators?
  • Have I got more bathrooms than when the current system was installed?
  • Is it likely that more or fewer people will be living in the home in the near future?
  • Do I want my new boiler to be in the same location as the current one?

Why upgrade?

In terms of boilers, upgrading would be considered installing a new system to cope with higher demand. That would typically mean the family has grown, for example if you’ve had children or a relative has moved in with you, or if you’ve had an extra bathroom or shower fitted. Perhaps you’re converting a house into several flats. It could simply be that the previous occupants of the home installed a boiler that was never powerful or versatile enough to cope with the demands of the household, but you’ve just put up with it.

A typical upgrade would be from a combi boiler to a system boiler, or from either of those to a heat only boiler. Each step up requires more hardware. From a combi to a system, you’ll need a cylinder. From a system to a heat only, you’ll need cold water tanks (normally in the loft). You’ll also need extra pipework and electronics to join the system together. These extra parts and labour will add to the cost.

However, if your current system can’t cope with the demands your family places on it, upgrading will probably pay for itself eventually. A combi boiler making hot water for several showers and baths every morning will not only wear out sooner; it might also work out cheaper in the long run to have a cylinder warming up water overnight, using both gas and electric immersion heaters. That way, everybody gets their morning shower and no more water needs to be heated until the evening.

Why downgrade?

Downgrading would be considered moving from a heat only setup to a system boiler, or either of those to a combi boiler.

You would usually do this if the number of people in your household has shrunk. If it’s just you in the home, or you and a partner, it’s unlikely you’ll regularly need to have two hot taps running simultaneously, so for the most part, a combi boiler will be fine (assuming you’ve got decent mains water pressure). If there are some rooms you no longer use, you may as well switch off those radiators, which again will mean less demand on your boiler.

Perhaps the previous occupants of the home had a large family, and you’re just a couple. There might be nothing wrong with the boiler, but it could end up being more efficient to downgrade and save money. If your boiler and cylinder are in good condition, you might even be able to sell them to save even more money. (However, some people might prefer to leave the equipment in place so that the system can be re-upgraded in future.)


If you’re replacing an old boiler with a newer version of the same type, the cost will be the least, assuming the rest of the system (pipework, electrics, cylinder and tank) are in good working order. The engineer should be able to swap it over in a day, and that means minimal labour costs.

However, if anything is changing (say you want the boiler moving from the kitchen to the utility room), the amount of labour and parts will inevitably rise, and so will the cost. You’ll need to extend or cut the gas pipe, the electrics will need to be re-wired, and there will need to be more pipework, both for mains water and for the household system itself. If you really can’t live with the system as it currently is now and it’s a price you think is worth paying, a qualified fitter will be more than happy to make the modifications.

Use our guide, and seek expert help

We hope this article gives a rough estimate of the costs involved with installing a new boiler, and that you understand it’s impossible to put a precise figure on it without knowing your exact needs.

We’d urge you to work through our Find a Boiler tool to discover what kind of boiler you need, then call in one of your local experts from our list of approved fitters to assess your home and your needs. Let them know what you need doing – from a simple boiler replacement to a complete new system with relocated boiler and extra radiators – and they’ll give you an estimate of the cost.

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