IS THE BOSCH Greenstar RI, heat only Boiler RIGHT FOR YOU?
The Worcester Bosch Greenstar RI is a regular or "heat only" boiler designed or small and medium-sized homes. Built for easy replacement of older boilers in kitchens like a Potterton Suprima, it features a simple knob temperature control and built-in frost protection (for when installed in a garage or loft area). The RI has been a staple of the Worcester line-up for so long that people are now replacing an RI with another RI, it is one of the most simple boilers to fit to replace an old non-condensing boiler and fits in a standard kitchen cupboard.
The RI comes in various outputs from 9kw to 30kw, (9,12,15,18,21,24,30) and are all cupboard fit, according to the Worcester website they all have dimensions of 600h x390w x270d
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, it 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 RI heat only boilers that have been installed to less than spotless systems, the expansion and contraction breaks the top hex seal and causes a slow leak. Worcester Bosch are aware of the issue and have a fixed price repair available, as always with Worcester Bosh 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, similar heat exchangers are found in some Ideal and Baxi boilers.
complexity of boiler
The Worcester Bosch RI has quite a complex build for a heat only boiler as you can see below, in order to keep the boiler small they have made some clever design implementations. The fan is positioned at high level next to the heat exchanger and is easily removed for servicing. These all contribute to a fairly compact boiler and it may look neat to a non-professional but to a servicing or repair engineer it is not what you want to see unless you're a Worcester Acredited Installer in which case I'm sure you'll disagree ;-)
Other than ease of access to parts there is the proximity to heat to be considered, although the components will be rated to be resistant against heat the long-term exposure will and does cause plastic parts to go brittle which can lead to failure. This is evident in the gas supply tube above the gas valve and below the fan which can break after heat and movement over some years.
Greenstar RI controls options
The Worcester Bosch RI as explained above was designed to replace the older range of kitchen cupboard dwelling boilers like the Potterton Suprima, because of this it has old fashioned controls options and they are - on and off. The Worcester RI has a Live/Neutral/Earth for supply, a pump feed out for an external pump and a switch live. There are no bus control inputs or weather compensation options, it is basic and that is quite deliberate.
The Worcester Bosch RI knows it's place and that is as a quick fix to provide a new and more efficient cost effective boiler replacement.
Third party controls
Technically pretty much any third party control will work, Nest, Hive, Honeywell all have options for mains switching. Although no controller will not be able to modulate the boiler output, many will be able to run on an intelligent TPI protocol which will maintain a level of comfort and avoid wasteful overheating.
WORCESTER BOSCH ACCESSORIES
WORCESTER BOSCH PRIMARY FILTER
Worcester offers multiple filters in metal and plastic, several sizes are available.
If the boiler is installed by a Worcester Approved Installer and one of their filters is installed then the maximum warranty can be applied.
WORCESTER BOSCH FLUE OPTIONS
WORCESTER BOSCH KEYLESS FILLING LINK
Size and Weight
The Worcester Bosch RI is quite a light boiler, it is well under the limit for a two man lift at 22.6kg dry weight. Most domestic heat only boilers are quite light though as they have very little inside them.
The external dimensions of the Worcester Bosch RI are dinky, it'll squeeze in anywhere. Many other heat only boilers are similar dimensions but the RI is very neat indeed.
As the RI is often destined for a cupboard Worcester have given guidance on compartment clearances for access and avoidance of combustible materials.
Worcester Bosch ri output
The RI is available in several sizes and LPG, the data given in their manual shows the maximum output at both high temperature and low temperature but doesn't give a minimum output, as a basic heat only this is not a surprise as it is not built for efficiency but convenience.
Consumer Reviews
The biggest problem with reviewing boilers is the difficulty of getting hands-on experience with all of them. I mean, what are we going to do, install twenty or thirty different boilers in our offices and use all of them for ten years straight before writing a review?
Well maybe not but due to the age of the RI and its prevalence we have installed and worked on tonnes so we can confidently pass our own judgement but first let's look at what the benevolent internet has to say....
All of the reviews discussed below are accurate as of the time I checked them in late 2019 but could shift if people add more reviews. We're not likely to see any significant changes in scores at this point, but we always try to be up-front with you on topics like this.
Expert Trades gave this unit an overall 5/5 score, but in its detailed explanation, they rated the Greenstar RI a little lower on features and value for the money.
One comment I saw several times is that Worcester Bosch hasn't done much to innovate their boilers over the last few years. They're clearly reliable systems, but they're not aggressively pursuing new features the way some other companies are. We can agree with this sentiment, although the recent news about their investigation into Hydrogen is encouraging I feel they have rested on their laurels for a long time now. The new Life range has had a cosmetic overhaul but the guts are the same as a CDI really.
Whether this is a problem or a feature depends on your point of view. I don't believe that every household wants or needs a lot of extra features on a heat only boiler system especially, there's only so much you can add before it becomes another type of product entirely. Many homes still want and need a quick and cost effective replacement and don't want the upheaval of converting the system.
While all reviews on Expert Trades were positive or average, a few people expressed concerns with the product build quality. I also saw notes on sharp edges, which isn't a major problem most of the time but could be a mild danger during the installation process.
We don't like relying on one source for information, though, so I eventually visited Trustpilot to look at their reviews. This was a good start; they gave Worcester Bosch a 4.7/5 after more than 13,500 reviews. This is pretty good considering their sheer volume of sales and that people are more likely to find the time to vote negatively I think.
Negative comments are often more informative than positive ones, so I reviewed those in more detail while researching this product.
While only 3% of all reviews on Trustpilot were negative, one of the most common complaints I saw in this range was difficulty getting engineers out to repair units. People reported often needing to wait several days to get someone out, and some experienced trouble with issues like parking or getting things scheduled. This would be true of any manufacturer, Worcester Bosch are renowned for their customer service including remedial visits.
I'd like to reiterate that these are clearly a very small number of customers; the overwhelming majority of comments were highly satisfied with the products.
Based on my experience, I think Worcester Bosch has managed to remain in a good position for a company. I don't believe it's realistic for a company to be too much better overall; there are always going to be bad installations, heavily-booked periods for engineers, and so on.
While frustrating in individual cases, you can alleviate many delay-based issues by keeping a record of several affordable local companies that can do the same type of work. This may cost a little more, but if time is of the essence, it may be your best choice.
Final Thoughts
Overall, we have a positive view of the Greenstar RI boiler system despite it's flaws. It's not the type of boiler we prefer to recommend because it is ancient technology compared to new options but it's reasonably affordable and built well. This boiler has a wide range of power levels to suit different sizes and styles of homes, which is another point in its favor and it neatly fits in a cupboard.
I think the Worcester RI is worth considering if you want a basic, reliable, regular boiler system for your home, without additional or advanced features to complicate its usage. The Greenstar RI is not the most advanced unit on the market, but I do think it's a viable choice for many households.
