Trying to figure out how much a new regular boiler with gas central heating costs for a large home?

I can guarantee you, you’re not alone. I hear from homeowners all the time about how confusing it is trying to work out the cost of getting a new central heating system installed, not forgetting all the other essentials that go along with it (like a new regular boiler and radiators).

With so many factors to consider, it can at times seem a bit like cracking the DaVinci Code!

I’m here to help, but having installed gas central heating in many different types of homes across Edinburgh throughout the years, I’m about to tell you something you might not want to hear; the cost varies dramatically depending on the size and set-up of your current home.

Then there’s the brand of regular boiler you choose, the type of radiators you want, and whether you want to pay for any extras such as a smart thermostat!

So, if you need a new central heating system and regular boiler for your home, I’m going to try and give you a better idea of how much you can expect to pay – including some of the biggest factors that can affect your overall costs.

But first…

Why choose a regular boiler?

A regular boiler is the classic choice if you’re looking for a heating system and boiler that will run off a hot water tank. For instance, your home might be very large with a high hot water demand, therefore just not suitable for the likes of a combi boiler.

When fitting a regular boiler with a new gas central heating system, the main advantages are that regular boilers can supply much larger outputs, such as 40kw, 50kw and 60kw – whereas with a system boiler, they only really go up to 35kw.

This makes regular boilers the best choice for very large properties that use up a lot of hot water. However, you should bear in mind that these are heat-only boilers, and still need to be connected to valves, cylinders and pumps. They can also have a separate remote expansion vessel.

TIP: The reason the expansion vessel is fitted separately is because a larger property with many radiators and tanks will require a bigger vessel than what is fitted in a system boiler.

Because you have all these extra parts to take into consideration on top of the actual boiler itself, it can take up quite a bit of space, so you’ll probably need a large walk-in cupboard or dedicated boiler room to house everything.

The average cost of a regular boiler and gas central heating

As I mentioned earlier, gas central heating costs with a new regular boiler will really be a bit unpredictable, as it really depends on a number of factors.

In this scenario, it’s especially tricky, as to fit a regular boiler, heating system, hot water tanks, pumps, valves and radiators. It would need to be specifically designed for a larger home with around 16 – 20 radiators.

I’d say your costs are going to be starting at around upwards of £11,000 incl. vat. However, it’s important to get a few quotes and then fine-tune your needs, such as the number and type of radiators, whether you want under-floor heating, unvented cylinder etc.

What else can affect regular boiler and central heating costs?

Because your overall costs are so individual, unfortunately I can’t give you a full cost breakdown without visiting your home. Think of it like buying a car or a tailored suit. 

However, what I can do is give you an idea of some of the main factors that can affect cost.

Brand of regular boiler

There are many reputable boiler manufacturers making good value regular boilers for large homes these days. From my own experience fitting many different brands of boilers over the years, models are only getting more reliable. However, there are still some cheaper options out there.

I tend to be a tad on the biased side as I know from experience that premium brands do tend to offer the best value for money in terms of guarantees. Despite this, I’d tell you to invest in the best quality boiler you can find, with a long guarantee. This will cover you if anything goes wrong.

Trust me, it could save you a lot of money in the long run!

Choosing a new hot water cylinder

If you want to opt for a new hot water cylinder, the cost to remove an old low-pressure bare copper cylinder with no insulation in favour of a higher volume indirect one, supplied and fitted, usually costs somewhere between £450 – £850 (depending on size: 120 – 300 litres).

However, if we were to supply and fit a high pressure unvented hot water cylinder for practically unlimited hot water and amazing flow rates to your large Edinburgh property, you could expect to add around £1,040 – £1,980 (120 – 300 litres) to your costs.

Type of radiators

When it comes to the matter of radiators, most homeowners opt for white pressed steel, and maybe a chrome towel rail for the bathrooms. Not everyone likes this style though, and you may instead choose column radiators or coloured radiators, which can be more expensive.

I recently helped out some homeowners who were undecided about designer radiators and if they were going to be worth it, by pricing up the standard Stelrad radiators and allowing them to check the prices of designer radiators. In the end, it was their call.

Type of flooring

And finally, if you currently have laminate flooring or sealed flooring, you may need to think about replacing it if there’s no other way for an engineer to access the area underneath. Again, if you have solid stone floors you may have to have the floors cut to install pipes. Especially if running pipes along the surface just doesn’t appeal.

Sadly, this will mean more upheaval and expense, but the end result will leave you with a much more professional job with concealed pipework.

Unfortunately, polished flooring will never go back the same way as it was, so you may want to consider getting a specialist contractor in to lift and relay it. Sorry about that.

From an engineer’s perspective

When you are designing this type of central heating system, you’ll find it can be very specialised work. That’s why it’s a good idea to call a number of engineers to find one experienced in installing this type of system in large homes.

I find it’s usually best to pick a company that specialises in this particular type of work, as they are the ones you can really rely on for advice to help you make the best choices for your home. Make sure an engineer calls for 2 – 3 visits to fine-tune your needs, as this is not a standard system.

For instance, we’ve got a customer at present which we priced up for standard radiators, a regular boiler with unvented cylinder, and partial underfloor heating.

However, after the first quote, the customer then decided to add three zones to the underfloor, and make the cylinder horizontal to fit in the eaves of the attic. He also chose column radiators that needed to be in specific colours, so all of this affected the original costs.

Ensure your final quote is a fully-inclusive, fixed price one – before any work starts. If there’s not a lot of difference in the quotes you get, I’d always choose the engineer with the most knowledge for the job.

You’ll probably also feel a lot more confident knowing the engineers are comfortable doing your type of project and will respect your home.

It’s also worth asking about locating your new regular boiler and cylinder close to each other to prevent heat loss. You may also want to check about smart energy efficiency controls to complement the new system.


I hope you’ve found this guide helpful when trying to determine your regular boiler and gas central heating costs for your large home. I wish I could be of more help, but unfortunately without a visit to your home, I can only give you the above estimate.

Saying that, I can answer any more specific questions you might have in the comments – and I promise to get back to you as soon as I can!