Best System Boilers in 2022

Looking for a brand-new system boiler? With so many options available, it could be difficult to find the right one for you.

Thankfully, in this guide we’ve narrowed things down to the best budget and best premium system boilers on offer in the UK market.

What is a System Boiler?

System boilers are well-suited to large homes with a higher heating and hot water demand than most. These boilers come with a separate water storage cylinder.

This allows them to provide a home with hot water on a continual basis. Combi boilers, on the other hand, can only supply hot water on demand.

An entry-level system boiler would suit a home with 1-2 bedrooms and a slightly higher energy demand than the average home. For higher heating and hot water demands, consider a premium model.

Best Affordable System Boilers

Let’s now look at some of our favourite system boilers. In this section we’ll explore the best budget-friendly system boilers out there.

We’ll discuss things like their features and pricing. If you only want to look at the best high-quality system boilers on the market, skip ahead to the next section.

Vokera Vision 25S System Boiler

One of your favourite low-cost system boilers is Vokera’s Vision 25S. Vokera provides a wide range of popular combi, regular and system boilers.

In fact, more than 1.5 million customers use Vokéra boilers/heating products throughout the UK and Ireland. Beyond that, Vokera has an excellent 4.4-star rating on Trustpilot. This is from nearly 1,400 reviews as of April 2022.

Features, Qualities and Warranty

While the Vokera Vision 25S has B rated energy efficiency, at 89.1% it is close to being A-rated. This 25kW wall mounted system boiler is also highly compact with dimensions of 405mm (W) x 715mm (H) x 248mm (D).

For that reason, it can be installed in a regular-sized kitchen cupboard. If your home has several bathrooms, this budget boiler could be the one for you. But that’s not all. The Vokera Vision 25S also comes with a warranty of five to seven years.

Installation Cost

As for the price tag, the Vision 25S costs around £650 if purchased directly from the supplier. The prices of boilers can, of course, vary depending on who you buy it from.

As for the overall cost of installation (including the standalone cost, labour cost, etc.), this stands at around £1,450 to £1,950. All in all, the Vokera 25S is a great deal if you want a reliable system boiler.

Vaillant ecoTec Plus System

This popular UK heating company has a 4.6-star rating on Truspilot and we’ve ranked it fifth overall when it comes to the top boiler brands.

While not always recognized as a budget brand, Vaillant does have some fantastic low-costing options on offer. Arguably chief among them is the brand’s ecoTec plus system boilers (although the ecoFit pure range has similarly affordable options).

Features, Qualities and Warranty

Since there is a wide price range covering each of the ecoTec Plus System boilers, our focus will be on the 12kW and 15kW editions (the other models being 18kW, 24kW, 30kW and 37kW).

While the ecoTec Plus 12kW system boiler has an energy efficiency rating of 92%, the 15kW model offers a 93% rating. Notably, both come with a ten-year warranty as standard. These boiler units also feature smart technology.

They know when there is less of a need for heating power and can reduce their output to just 16% of their max power levels if deemed suitable. This will in turn keep your energy bills lower.

It also features a backlit display, stainless-steel heat exchanger and high-quality components.

Despite the 12kW and 15kW models being more so budget options, the Vaillant ecoTec Plus clearly has plenty to offer and provides customers with good value for money. Its dimensions stand at 440mm (W) x 720mm (H) x 406mm (D).

Installation Cost

For the 12kW model, you’d face a standalone price of around £800 or for the 15kW unit, around £900. This would make the cost of installing these boilers approximately £1,600 to £2,100 for the former or £1,700 to £2,200 for the latter.

Best Premium System Boilers

Now that we’ve looked at our favourite budget system boilers, let’s explore the top high-end options. Again, we’ll look at the features, qualities, warranties and pricing of these units.

Worcester Bosch 4000 System Boiler

Coming in fourth place on our list of the best boiler brands is UK boiler company Worcester Bosch. Several of their boilers have also secured the Which? Best Buy Award for an entire decade running.

Customers give the brand a 4.6-star rating (from almost 30,000 reviews) on Trustpilot. This puts the brand in third place on the list of the most highly rated boiler companies on Trustpilot.

Features, Qualities and Warranty

This boiler can be purchased in a variety of models with different outputs. They come with efficiency levels of 94%.

The Worcester Bosch 4000 also has a warranty of up to ten years. Among the most notable features of this boiler are its LCD touchscreen, optional external weather detector and advanced hydrogen technology.

Looking a bit more at the external weather detector, if used, this technology allows the boiler to adjust temperature levels based on how the weather is changing outside.

Think of those spring days when the temperature drops fast and unexpectedly in the evening time. Worcester Bosch’s external weather detector would have you covered by adjusting the temperature in real time.

Not only that but this system boiler is promoted as being exceptionally quiet with Quiet Mark accreditation to back this up. It is also compact with its dimensions being 400mm (W) x 724mm (H) x 310mm (D).

Installation Cost

The Worcester Bosch 4000 costs about £1,100 standalone with the overall installation cost being approximately £1,900 to £2,400.

Viessmann Vitodens 100-W Gas System Boiler

This high-quality European brand is our favourite currently on the UK boiler market. Viessmann products are recognized for their reliability, quality and warranties among other aspects.

The brand also has customer satisfaction to back this up with a 4.4-star rating on Trustpilot from some 3,400 reviews.

Features, Qualities and Warranty

The Vitodens 100-W is a wall-mounted 32kW boiler. With this output level and as a system boiler, it could meet the demand of a home with about 20 radiators.

It also comes with a fantastic A-rated energy efficiency rating of 94%. As for its size, the dimensions of the Vitodens 100-W are 400mm (W) x 700mm (H) x 360mm (D).

In addition, customers who purchase this Viessmann product can benefit from a warranty of up to twelve years.

While the standard warranty is just five years, you can avail of an additional seven by having a Viessmann Trained installer fit the boiler for you. The Vitodens 100-W system boiler has also been certified to run using natural gas with a 20% hydrogen blend.

Installation Cost

In terms of pricing, the Vitodens 100-W system boiler has a standalone cost of around £1,200. This brings the total installation price to about £2,000 to £2,500.

As you can see, the cost of a boiler like the Vitodens 100-W is clearly several steps above that of budget boilers. However, for that extra money you get better quality and more reliability and arguably better value for money overall.

Worcester Bosch Greenstar 24i System

Next up we have another system boiler from this top UK heating company. Ultimately Worcester Bosch and Viessmann earn their places in this list as two top-dog competitors.

Features, Qualities and Warranty

This boiler features 94% efficiency and the ability to recycle heat from exhaust gases. As a result, the Greenstar 24i System has running costs that are up to 30% lower than some older boiler products.

But that’s not all. The Greenstar 24i can be installed easily and quickly. On another note, this appliance is LPG compatible. This Worcester Bosch boiler comes with a five-year warranty.

Arguably though, the Greenstar 24i’s stainless steel heat exchanger falls far short of the quality offered by rival brand Viessmann. As for the dimensions of this system boiler, they are 400mm (W) x 710mm (H) x 330mm (D).

Installation Cost

The supply price of this boiler stands at approximately £1,100. Again, as with all boilers reviewed in this guide, the exact price would depend on the supplier. The overall cost of having it installed would likely land between £1,900 and £2,400.

Best System Boilers: Verdict

Today we’ve looked at five of the top system boilers on the market right now. Choosing the ideal system boiler for you would depend on things like your budget and heating/hot water needs.

If you want a budget option, while the Vokera Vision 25S is noticeably cheaper than the Vaillant ecoTec Plus System, Vaillant’s boiler has many advantages.

With higher energy efficiency, a better warranty and smart technology, we believe that Vaillant’s offering provides better value for money overall.

However, if you’re willing to spend more, the choice is a little less clear. For instance, all three boilers featured in our premium system boilers section come with 94% energy efficiency.

With that said, when you take everything into account including technology, warranty, and pricing, we’d suggest that the Vitodens 100-W gas system boiler takes the cake.

Leave a comment


Ut ut eleifend elit. Morbi tortor sem, lobortis vel urna malesuada, molestie imperdiet lectus. Nullam maximus vel diam eu porttitor.

Mark Doe


Ut ut eleifend elit. Morbi tortor sem, lobortis vel urna malesuada, molestie imperdiet lectus. Nullam maximus vel diam eu porttitor.

Maria Doe


Ut ut eleifend elit. Morbi tortor sem, lobortis vel urna malesuada, molestie imperdiet lectus. Nullam maximus vel diam eu porttitor.

Marcus Doe