System Boiler Costs/Prices UK

Thinking about installing a system boiler?

You’re in the right place! With thousands of installations completed nationwide, we have the expertise you need.

In this guide, we’ll delve into the potential costs of installing a new system boiler and examine the average running costs you can expect.

Let’s get started!

PS - we fit new system boilers with gas safe installation nationwide. Simply answer these questions, get your fixed price and you could get it installed as quick as tomorrow.

What is a System Boiler?

Think of a system boiler as the middle child of the boiler world: not as compact as a combi, not as old-school as a regular boiler.

It works with a hot water cylinder (no loft tanks needed) so you get:

• Loads of hot water at once – great if your house has multiple bathrooms.

• Decent water pressure – taps and showers don’t dribble when used together.

• Future-proof options – can hook up nicely with solar thermal panels or low-carbon tech down the line.

Downside? You’ll need cupboard space for that hot water cylinder, and they’re pricier to fit than combis.

Cost of Installing a System Boiler in the UK

In 2025, you’re realistically looking at anywhere from £1,700 up to £5,000+ for a system boiler installation.

That figure covers both the boiler itself and the labour to fit it – but extras (like new cylinders, extra pipework, or tricky installs) can nudge the bill higher.

Here’s the no-nonsense breakdown:

• Entry-level swap (£1,700 – £2,200) - Small system boiler, straight swap, easy job, no major extras.

• Mid-range install (£2,500 – £3,500) - Typical 3–4 bed home, new boiler plus a neat, standard installation.

• High-end job (£3,800 – £5,000+) - Large output boiler (35kW+), new or upgraded cylinder, complex pipework, or switching from a combi to a system setup.

What makes the price swing?

• Boiler size & quality - Bigger kW output = bigger price tag.

• Installation complexity - Extra pipework, relocating boilers, or swapping systems costs more.

• Cylinder needs - If yours needs replacing or upgrading, add it to the bill.

• Where you live - Labour is generally cheaper in the North, Scotland, and Northern Ireland - and pricier in London and the South East.

🎥 Prefer video? Check out our YouTube video explaining the average new boiler costs below:

Cost of Popular System Boilers

Some of the best brands worth considering if you want to have a system boiler installed include Worcester Bosch, Ideal, Viessmann and Vaillant.

Here are some of the most popular system boilers on the market and their estimated price tags:

When seeking the right boiler for you, it’s important to set aside a sufficient amount of time to weigh up your options.

You’ll want to look at boilers that match your budget, preferences and the heating and hot water demands of your home.

If in doubt, consult with a qualified heating engineer.

How Much Does It Cost to Run a System Boiler?

As of autumn 2025, Ofgem’s price cap puts gas at around 6.3p per kWh. Electricity (for pumps, controls, and unlucky souls with electric boilers) is about 26p per kWh.

So, for a typical home using 12,000 kWh of gas a year with a 90% efficient boiler:

If your home’s draughty, your kids love marathon showers, or you like your living room at “tropical conservatory” levels of warmth, expect more.

System Boiler Pros and Cons

Now that we’ve explored the potential installation cost and running costs of a system boiler, it’s worth exploring the advantages and disadvantages of this type of boiler.

This will help you to weigh things up if you’re unsure whether to go with a combi, system or heat-only boiler.

Advantages:

• Can store lots of hot water for a continual supply which is not true of a combi boiler.

• Use up less space than a heat-only boiler.

• Great for those with a high heating and hot water demand.

• Compatible with solar energy power.

• Offer mains pressure hot water to household taps.

Disadvantages:

• Generally, less efficient than combi boilers.

• Use up more space than combi boilers.

• Tend to be a bit more costly than combi boilers.

• May provide more power than is needed.

Should You Get a System Boiler?

Here’s the quick and dirty way to work it out:

• Small pad, single bathroom, light hot water use? Don’t waste your money. A combi boiler will do the job for less cash and less hassle.

• Bigger home, two or more bathrooms, everyone showering at once? A system boiler is your best mate. It’ll keep the hot water flowing without tantrums.

• Grand designs mansion, ancient tanks lurking in the loft? You might actually need a heat-only (regular) boiler to keep things ticking over.

Looking for the best deal on a new System Boiler? 

If you’re aiming to get the best deal on a new boiler, consider getting a quote from us, here’s why:

• Gas Safe installation within 24 hours.

• Thousands of satisfied customers with an average score of 4.9 on Trustpilot, surpassing the market leader.

• Which? Trusted Trader: Heatable is proudly recognised as a Which? Trusted Trader.

• Price match guarantee: We will match any like-for-like cheaper quote.

• Flexible payment options, including interest-free finance.

• Up to 12-year guarantee on selected boilers.

• Fixed price guarantee: No hidden costs.

• Save your quote and decide later.

• Get an instant fixed price on a new boiler, here.

To learn more about boilers, visit our advice section, check out our YouTube channel, or read customer testimonials here.