What Boiler is the Number 1 Boiler in the UK?

Our clients frequently ask us: what is the number one boiler in the UK? Whether they’re chatting with one of our consultants via:

• The live chat window
• Sent an email
• Or have you called our automated helpline

The answer is always the same: It depends on your needs, budget, and the constrictions of your property.

However, a few boilers stand out from the crowd.

Before we recommend our top boiler in the UK market, let’s discuss how you can determine the best boiler for your home.

How To Determine The Number 1 Boiler For Your Home

There isn’t a one-size-fits-all solution when it comes to boilers. Even within the same block of flats, each apartment could require a different boiler setup due to factors like sun exposure, drafts, and insulation.

A great starting point for selecting the best boiler is to take our simple questionnaire.

But for those who prefer to choose on their own, here’s a guide to get you started.

What Type of Boiler Do You Have?

There are three types of boilers:

• Combination (combi)
• System
• And regular

Back boilers, which are found behind older fireplaces, are no longer installed due to their inefficiency.

What Type Of Home Do You Live In?

The type of home you live in plays a key role in determining the right boiler. Each boiler type is better suited to a different type of home.

Let’s explore the best options for different homes:

Combi Boiler

A combi boiler is best suited for small to medium-sized homes, such as a flat. Its compact dimensions make it a great space-saving option.

Combi boilers provide instant hot water on demand and are simple systems that can be neatly tucked away.

However, they have limitations, including their reliance on mains water pressure and their limited hot water supply, which may not meet the needs of larger households.

System Boiler

A system boiler is larger than a combi and ideal for medium to large homes with 2 to 3 bathrooms. It can handle moderate to high hot water demands.

System boilers have a hot water cylinder that stores water for later use, offering better temperature control and less reliance on mains water pressure.

However, they require more space and are less efficient than combi boilers because they need to maintain heat in the hot water cylinder.

Regular Boiler

A regular boiler is best suited for large homes with multiple bathrooms and high hot water demand. These boilers are often found in older homes and are ideal for replacing an existing system. They work well with low mains pressure, using a gravity-fed system.

However, they require the most space and are less efficient at retaining heat.

For those just looking for a simple table comparison, here’s a quick summary:

Boiler Size Options

Every boiler model will be available in different power outputs (or sizes). A boiler’s output is measured in kilowatts (kW).

Selecting the correct boiler type and size will depend on several factors in your home, such as:

• Number of radiators
• Number of bathrooms
• And the insulation of your property

As a general guide for what power you need for your home:

• A small-sized home with 1 to 2 bedrooms will need a boiler that makes 24-30kW.
• A medium-sized home of 3 to 4 bedrooms will need a boiler that makes 30-35kW.
• A large-sized home of 5+ bedrooms will need a boiler that makes 35-42kW.

Efficiency And Environmental Impact

All boilers installed in the UK since 2016 must comply with the Energy Related Products methodology (ErP) rating system, ensuring at least 92% efficiency.

It’s worth mentioning that some new gas boilers can reach efficiency levels of up to 98%.

It’s also important to remember that the last gas boiler may be installed in the UK by 2035 to meet the government’s ambitious Net Zero Carbon Emission goal of eliminating greenhouse gas emissions by 2050.

With this deadline in place, selecting the best boiler in the UK may need to incorporate hydrogen fuel compliance.

Cost And Operational Budget

Many UK citizens want to keep costs low. This means reducing the unit’s initial cost and ensuring the boiler keeps operational costs low.

According to Checkatrade, the average starting cost of an electric combi boiler is about £1525.00, while a new gas combi boiler is around £1500 + VAT.

These prices are for the boiler unit and do not include labour or additional components. Gas boilers are usually cheaper because there are more choices.

Running a gas boiler is still far cheaper than running an electric boiler.

Between 1 October and 31 December 2024, the energy price cap is set at £1717 per year for a typical household that uses electricity and gas and pays by Direct Debit.

Comparing the cost per kWh and the daily standing charge:

• Electricity: 24.50 pence per kWh, 60.99 pence daily standing charge
• Gas: 6.24 pence per kWh, 31.66 pence daily standing charge

Warranty And Support

Brands that believe in their products will offer comprehensive warranties and guarantees. Most major brands offer warranties of up to 10 years.

Always read through the agreement and confirm what is covered, whether it can be extended, and what violates it.

Another major factor to consider is after-sales support. After all, nothing is worse than investing in a product with a long lifespan only to discover that the company doesn’t answer its phones.

A reliable boiler brand will have a strong customer service network, with easy access to engineers and spare parts if needed.

Brand Reputation And Customer Reviews

A brand’s reputation is built over time. For a brand to build a solid reputation, it needs to meet the following:

• Customer’s expectations
• Product’s performance
• Brand’s legacy
• And reliability

Also, user reviews and industry awards won over time can provide valuable insight into a brand’s reputation.

Using review websites like Trustpilot can give you a clear picture of how reliable a specific boiler is.

It is time to reveal our top choices for the best combi, system and regular boiler in the UK.

The Number One UK Boilers

Now it’s time to reveal our picks for the best type of boilers in the UK.

Best Combi Boilers

Our top three choices for the best UK combi boiler are:

Viessmann Vitodens 100 W

The Viessmann Vitodens 100 W range is a German-engineered gem that stands out due to its high-efficiency rating and proven reliability.

It is also hydrogen-ready and has a stainless steel heat exchanger. The Vitoden 100 W is available in 30kW or 35kW power outputs.

The model range has also won several industry awards. As you’d expect, the boiler comes with a solid warranty of ten years, which can potentially be extended to 12 years.

Worcester Bosch Greenstar 8000 Life

One of the brand’s most recommended models for reliability is the Worcester Bosch Greenstar 8000 Life.

The Worcester Bosch Greenstar 8000 Life is known for its efficiency (94%) and powerful performance, and the boiler can support smart thermostats. Customers can extend the warranty for up to 12 years if they want.

Vaillant ecoTEC Plus

The Vaillant EcoTEC Plus (825, 832, 835, and 838) is a versatile option that operates at a high-efficiency rate and offers several kW output options.

Vaillant has developed a range that offers an outstanding balance of performance, affordability, and a solid 10-year warranty. It is also hydrogen-ready.

Unfortunately, it is not currently available via WarmZilla.

Best System Boilers

While the type of boiler has changed, the brand’s model ranges have not. Our top system boiler is the Viessmann Vitodens 100 W.

The Vitodens range has output options of 19kW, 25kW, and 32kW. It also offers a 10-year warranty and an astonishing efficiency rating of 98%.

Worcester Bosch Greenstar 8000 Style comes in second place. The model range is known for its sleek design (with a black finish) and was available via WarmZilla in a 30kW or 35kW output. However, this range is currently out of stock.

If you need an alternative option, the Worcester Bosch Greenstar 8000 Life in 30kW and 35kW options are available for installation immediately.

Third place goes to the popular Vaillant EcoTec Plus (615, 620, 625, and 630).

The most efficient boiler in the range is the 25kW 625 System Boiler, which has an efficiency rating of 94%. It’s also earned the reputation of being incredibly quiet.

Best Regular Boilers

As you may expect, the top performer in this category is the Viessman Vitodens 200 W. While not available on WarmZilla yet, it is a state-of-the-art heating system.

As a premium product, it boasts a high-efficiency level, includes loads of advanced technology features, has a touch screen, and can be controlled via an app.

The Worcester Bosch Greenstar 8000 Style graces us with its presence in the second spot. It offers up to 92% efficiency and is compatible with smart thermostats like Bosch EasyControl. Available in 30kW, 35kW, and 40kW power options, it also comes standard with a 10-year warranty.

Third place goes to the Vaillant ecoTEC Plus Regular. Currently available in various outputs, it is a compact regular boiler perfect for medium—to large homes.

The ecoTEC Plus Regular is also highly efficient (94%) and features a modulation system that adjusts power usage based on heating demand, which can help reduce fuel consumption and emissions.

While this is a lot of information to take in, you can always talk to one of our many consultants for more details.