There are a number of factors to consider when buying a combi boiler. Price might be your first consideration. As with other consumer purchases, compromising on quality to reduce the initial cost may mean paying a price later in repairs and inconvenience. Cheap boilers are often difficult to repair and hard to find parts for, which means heating engineers may be reluctant to work on them.

Long-Term Peace of Mind
Long-term peace of mind is important to most boiler buyers. Some boilers offer up to 14 years of parts and labour warranty, meaning that if the boiler goes wrong, the manufacturer will fix it for free.

Minimum Heating Output
Another factor to consider is the minimum heating output. This means that the boiler can be adjusted to match the size of the heating system in your house. A combi boiler with a hot water output of 30 kW doesn’t need to work hard to heat your radiators. By lowering the heating output to match the size of your system, you will be wasting less energy. If your boiler’s minimum heating output can only be lowered to 10 kW, you’ll probably be burning more gas than necessary. The lower this number is, the more efficient your boiler.

What size boiler do I need? (theheatinghub.co.uk)

Hot Water Flow Rate
We also mention hot water flow rate, which is important when choosing your new combi boiler. Generally speaking, the higher the hot water output in kilowatts, the better the flow rate will be.

Let’s take a look at some of the most popular brands and see how they’re regarded by owners and installers. The scores shown against each manufacturer are taken from the Which? or Trustpilot websites, based on feedback from both installers and householders.

Worcester Bosch | Which? Score: 84%
Reviewers overwhelmingly had a great experience with this company. Customers consistently praise the company's service and products, highlighting their professionalism, efficiency, and knowledge of the engineers. Clear communication, helpfulness, and politeness of staff are also frequently noted.

Hot water flow rate: up to 16.4 l/min
Pros:

• Excellent reliability, highly recommended by Which?
• Parts widely available

Cons:

• Doesn’t work to maximum efficiency unless you use their own controllers
• Some repairs difficult

Common faults: Gas valve seizing, fan failure

Vaillant | Which? Score: 81%
Customers frequently commend engineers for efficient, knowledgeable, and friendly service. Reviewers often note individual engineers' professionalism, clear communication, and quick problem-solving.

Hot water flow rate: up to 15.9 l/min
Pros:

• Boilers very popular with users and engineers
• Easy to work on and parts widely available
• Excellent build quality and reliability

Cons:

• Fairly expensive
• Doesn’t work to maximum efficiency unless you use their own controllers

Common faults: Circuit board cutting boiler out, leaking diverter valve

Glowworm | Which? Score: 70%
The majority of reviewers reported highly positive experiences. Customers recognised the efficiency and quiet performance of Glow-worm boilers, frequently noting advantages over previous models or competing brands.

Hot water flow rate: up to 12.5 l/min
Pros:

• Cheaper to buy
• Good reliability

Cons:

• Build and component quality rated lower than other manufacturers
• Doesn’t work to maximum efficiency unless you use their own controllers

Common faults: Leaking diverter valve, circuit board failure

ATAG | Trustpilot Score: 4.8/5
Most reviewers report an excellent experience. Customers frequently commend the quality of products, pointing out efficient and quiet operation. Buyers also note reliability and a noticeable drop in energy costs.

Hot water flow rate: up to 16.1 l/min
Pros:

• High-quality parts
• Long warranty, lifetime warranty on main heat exchanger
• Heat recovery system for hot water adds efficiency

Cons:

• Historic problems with parts availability and aftercare (recently addressed)

Common faults: Unknown

Ideal | Which? Score: 77%
Ideal’s Logic and Vogue ranges run more cheaply than the average model. Most owners are satisfied, with a four-star customer rating.

Flow rate: up to 16 l/min
Pros:

• Very popular brand at an affordable price

Cons:

• Difficult to connect to the most efficient controllers
• Can become unreliable if not properly serviced

Common faults: Sump leaks, ignition problems

Baxi | Which? Score: 74%
Headquartered in Warwick, Baxi is one of the biggest boiler manufacturers in Europe, offering a lot of choice. Users have high satisfaction rates, resulting in a four-star customer score.
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Hot water flow rate: up to 16.4 l/min
Pros:

• Good value

Cons:

• Less well regarded by installers than many other brands
• Doesn’t work to maximum efficiency unless you use their own controllers

Common faults: Fan, burner, circuit board unit failure

Choosing the right boiler for your house is a big decision. You want your boiler to give you years of reliable service, so getting the right one for your property is important.

As with most other things, you get what you pay for, so its never advisable to go for the cheapest boiler you can find.

We would always recommend choosing from one of the most trusted and renowned manufacturers.

To help you make an informed choice about your next boiler, we have reviewed 3 of the best quality boiler brands on the market.
 
Worcester Boilers

Overview:
Worcester Bosch is a highly regarded brand in the boiler industry, known for its reliable and efficient products. They offer a range of boilers for all homes of all sizes.

Performance and Efficiency:
Worcester boilers are praised for their high efficiency and robust performance. They typically feature a high efficiency rating (90% and above) and have received numerous accolades for their innovation and energy-saving capabilities.

Customer Feedback:
According to Which? reviews, Worcester Bosch consistently receives high ratings for reliability and customer satisfaction. Trustpilot reviews echo this sentiment, with many users highlighting the long lifespan, minimal maintenance needs, and excellent customer service.

Pros:

• High efficiency
• Reliable and durable
• Excellent customer service

Cons:

• Higher initial cost compared to some competitors

Vaillant Boilers

Overview:
Vaillant is another leading boiler manufacturer, recognised for its commitment to quality and sustainability. They provide a diverse range of boilers suitable for various household needs.

Performance and Efficiency:
Vaillant boilers are known for their efficiency and environmental friendliness. They often incorporate advanced technology to reduce energy consumption and carbon footprint. Many models boast an efficiency rating of over 90%.

Customer Feedback:
Which? reviews rate Vaillant boilers highly for their reliability and ease of use. On Trustpilot, customers generally appreciate the efficient performance and quiet operation of Vaillant boilers. However, there are occasional mentions of installation challenges and the need for professional servicing.

Pros:

• Energy-efficient
• Environmentally friendly
• Quiet operation

Cons:

• Installation can be complex
• Professional servicing recommended for optimal performance

Atag Boilers

Overview:
Atag is a premium boiler brand that emphasises high-quality engineering and innovative design. They offer an industry-leading 18-year warranty on their boilers, as well as lifetime warranty on their stainless steel heat exchangers.

Performance and Efficiency:
Atag boilers are renowned for their exceptional efficiency, often achieving ratings well above 90%. They incorporate innovative technology to ensure optimal performance and energy savings.

Customer Feedback:
Which? reviews highlight Atag boilers for their reliability and superior build quality. Trustpilot reviews are generally positive, with customers praising the long-term performance and efficiency. However, some users mention that Atag boilers can be more expensive upfront and may require more specialised maintenance.

Pros:

• Superior efficiency
• Innovative design
• High build quality

Cons:

• Higher upfront cost
• Specialised maintenance may be required

Conclusion

When choosing between Worcester, Vaillant, and Atag boilers, each brand offers distinct advantages:

• Worcester Bosch stands out for its reliability, excellent customer service, and overall high customer satisfaction. It is ideal for those looking for a durable and efficient boiler with strong after-sales support.
• Vaillant excels in energy efficiency and environmentally friendly features. It is a great choice for eco-conscious consumers seeking a quiet and efficient boiler.
• -Atag offers premium quality and innovative design, making it suitable for users willing to invest in a high-end boiler with exceptional efficiency.

Ultimately, the best choice depends on individual preferences and specific needs, such as budget, desired features, and the importance of customer service. It is always best to discuss the most suitable boiler type and brand with heating adviser.