Every year, the consumer research group Which? Surveys over 12,000 boiler owners and 166 heating engineers to find the best and worst boiler brands. They look at several factors, including:
- Reliability
- Customer satisfaction
- Engineer recommendations
- Build quality
- Availability of spare parts
- Ease of repairs and servicing
No other organization collects this much data on boilers, making Which? a reliable source for reviews. Issues like E 1 1 9 boiler pressure? can impact performance. So, which brand performed the worst this year?
The Worst Boiler Brand of 2025
The lowest-rated boiler brand in this year’s survey was Ferroli. Based in Burton-on-Trent, this Italian company received poor ratings:
- Reliability: 3/5
- Engineer recommendation: 1/5
- Customer satisfaction: 2/5
- Overall Score: 35%
This was the lowest score among all brands, with Vokera coming in second to last with 50%. The Ferroli HE 27C model received particularly bad feedback, with no notable positives mentioned. Other models like the HE 32C and HE 38C also performed poorly.
Boiler Efficiency – Is There a Worst Brand?
A boiler’s efficiency determines how much energy it converts into proper heating. Since 2018, the Boiler Plus law has required all new boilers to be at least 92% efficient. This means that modern boilers are generally similar in efficiency.
The Worst Boiler Warranties
A boiler’s warranty is an essential factor to consider when buying a new one. A longer warranty usually means better quality and support. However, not all brands offer the same warranty length or level of service.
- Some brands only provide a 1-year warranty, which is not helpful if problems arise.
- Worcester Bosch, on the other hand, offers a 10-year guarantee (if purchased through specific retailers), which is more reliable than a standard warranty.
A guarantee means the manufacturer will repair or replace your boiler within a reasonable time. A warranty, however, only promises to investigate the issue—it does not guarantee a free fix.
Worst Boilers by Price
Buying the cheapest boiler is not always a good idea. The Which? Survey shows that lower-priced boilers often have reliability issues. Below is a price comparison of some common boiler brands:
- Vokera Compact 25 – A budget-friendly option, priced at around £600.
- Ferroli Sky Eco – One of the cheapest boilers, costing about £550.
- Heatline Capriz 24 – An even more affordable budget option, available for £500.
- Alpha E-Tec 28 – A mid-range boiler with better reliability, priced at approximately £900.
- Vaillant EcoTEC Pro 28 – A higher-quality mid-range boiler, costing around £1,200.
- Viessmann Vitodens 050 – Another mid-range option, available for £1,000.
- Worcester Bosch Greenstar – A premium boiler from a highly rated brand, priced at £1,200.
Which Boilers Are Recommended?
If you want a reliable boiler, Worcester Bosch is one of the best choices. It has been a Which? Best Buy winner for 10 years, offers a 10-year guarantee and provides excellent customer service. Other good brands include Vaillant and Viessmann.
