Is the Worcester Bosch Greenstar I right for you?
The Worcester Bosch Greenstar I is the manufacturer's most popular boiler and has three different product lines, each of which is suitable for different purposes. In this review, we're going to cover the three models and how they differ from each other, as well as our overall thoughts on these units.
Worcester Bosch Greenstar I combi boiler is the primary unit of the line, with dimensions of 710 x 400 x 330mm and a flow rate of 9l/min (for the 25i model) or 10.8l/min (for the 30i model).
Worcester Bosch Greenstar I System boiler 9-24kw is a lesser known but equal output (for heating) unit, it is the same dimensions and mimics the combi version for heating output.
The Worcester Bosch Greenstar I System boiler 27 and 30kw is a larger output version of the core line, made for larger homes. The Worcester Bosch Greenstar 24I (and lower) models all have the "kebab" heat exchanger from the RI range, the Worcester Bosch Greenstar 27I (and above) have the CDI heat exchanger which is shorter. The CDI hex is shorter but has a higher capacity. The CDI hex is a lot easier to clean and gets a better thermal transfer as the baffles give a larger surface area.
The I range includes a low-energy pump, a maximum A+ ErP efficiency rating when installed with the smart internet connection, and a condensate discharge system similar to their Condensure that helps reduce the chance of freezing in temperatures down to -15 degrees C.
It's worth noting that the anti-freezing measures are only rated for up to 48 hours and require 32mm piping so consideration still has to be made to the outlet.
Build quality
Heat exchanger
Worcester Bosch boilers have Aluminium heat exchangers which are very good at thermal conduction and are cheap to produce compared to Stainless Steel, but also has far higher thermal expansion which will lead to movement over time and can have the issue of seals leaking. This problem is particularly evident in some Worcester Bosch I boilers that have been installed to less than spotless systems. Worcester Bosch are aware of the issue and have a fixed price repair available, and their after care is exceptional.
Aluminium is easier to form into complex shapes which makes it the ideal choice for heat exchangers with designs found in Worcester Bosch boilers.
More care must be taken with the water quality of Aluminium heat exchangers. Worcester Bosch also do not recommend their boilers are filled with water softeners in the property as softened water reacts with Aluminium.
Greenstar I System (9kW to 24kW)
The lower output of the system boilers, this unit is designed to function in small and medium-sized homes while providing a steady supply of heat and hot water on demand. This is the same size as the combi boiler at 710 x 400 x 330, which makes it suitable for installing next to, or inside of, most kitchen cabinets and other common installation places. Notably, this unit is also solar compatible.
Greenstar I System Boiler (27kW to 30 kW)
While these units again share a name with others, they're functionally a different boiler entirely. At 690 x 390 x 280, these higher-powered boilers are noticeably smaller than their cousins and, therefore, much easier to fit into smaller, limited areas.
Other Reviews
The great challenge of writing reviews for boilers is the fact that they're long-term products, and it's tough to test individual models the same way we test other products.
Trustpilot gives Worcester Bosch a 4.7/5, with 80% of reviews marking the company as great and another 12% rating it good. Only 3% of reviews were outright negative, which is an extremely positive indicator for the company.
Final Thoughts
Overall, we recommend the Greenstar I from Worcester Bosch, regardless of whether you're going for the combi or the system boilers. They're clearly high-quality units. Most people seem to have few or no problems with these boilers for their expected lifetime, and you're probably going to have a positive experience if you choose this unit.
