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Worcester Bosch Greenstar 12i System Boiler – Review

In this Worcester Bosch boiler review, we’ll take a closer look at the Greenstar 12i System Boiler – a popular choice for smaller households. We’ll give you a full run-down of its features to help you decide whether it’s the right choice for your home.

First off, here’s a bit of information about Worcester Bosch, the brand behind the boiler. For those who don’t know, Worcester Bosch is the UK’s leading boiler manufacturer and has been in business since the early 1960s. The brand is known for its high quality, energy-efficient boilers, which are designed to meet the needs of domestic properties of all sizes.

The Greenstar i is Worcester Bosch’s most popular system boiler. Shall we find out if it’s the one for you? Let’s get started.

Will the Worcester Bosch 12i System be suitable for my home?

The Worcester Bosch 12i System boiler is an excellent choice for small 1 to 2 bedroom houses, as well as flats and bungalows. It has a central heating output of 12kW and will comfortably accommodate up to 10 radiators.

The advantage of installing a system boiler, like the Worcester 12i, is that it can supply hot water evenly to all taps at the same time. This means someone can run hot water in your kitchen, while you are running it in your bathroom. No one will have to wait! System boilers need a cylinder to store hot water, but they don’t require a loft tank, which is another advantage for those with limited space. The Worcester Bosch 12i System boiler is also compatible with solar panels, allowing you to lower your energy costs, while also reducing your carbon footprint.

As we previously mentioned, the 12i will only heat up to 10 radiators, so if you have more than 10 in your home, you’ll be better off looking at one of the higher output models, like the Greenstar 18i, 21i or 24i. For even larger homes, there’s also the Worcester Bosch Greenstar 27i System and 30i System boilers.

If you’d like to compare the Worcester Greenstar boiler with an offering from another brand, we suggest the Vaillant ecoFit Pure 612 system boiler. Like the Worcester Greenstar 12i, it has a central heating output of 12kW but is slightly more compact in size, measuring 700x390x295mm.

Worcester Greenstar 12i Controls

The Worcester Bosch 12i System boiler has a user-friendly control panel, hidden under its front flap. There you will find information on the boiler operation and can adjust the temperature to your liking, using the buttons.

It’s essential that all boilers now comply with Boiler Plus – industry regulations that came into force in April 2018. The Boiler Plus regulations specify the energy efficiency levels all boilers must meet. They also require boilers to have both time and temperature control functionality.

The easiest way to ensure compliance is to link your Worcester Greenstar boiler with a smart thermostat. This will give you more control over your boiler’s running cycles and provide the opportunity to optimise its efficiency, resulting in lower running costs. This particular boiler can be used with the Bosch EasyControl or Worcester Bosch Wave smart thermostat with their smartphone apps. Use them to pre-heat your home, turn off the heating in unused rooms and check your energy usage from any location.

Alternatively, you can choose a smart thermostat from a third party, like the Nest and Hive, both of which are very popular with homeowners. Like the EasyControl, they have their own apps, which provide greater control over your heating system and allow you to make changes, whether you’re at home or away.

Fancy getting a smart thermostat for free? Hometree gives all customers a Honeywell Lyric T6 Smart Thermostat with every boiler installation. Although the device itself offers quite basic functionality, this can be further extended with the use of its handy smartphone app. Enhance your boiler’s performance and gain greater control over your heating system, without spending any extra money. We thought you’d like the sound of that!

Worcester Bosch 12i System Size

The Worcester Bosch 12i is the brand’s most popular wall-mounted system boiler and measures 710x400x330mm. Although it won’t fit in a standard size kitchen cupboard, it isn’t overly bulky and should, therefore, fit neatly between them. Just get your tape measure out for a quick check!

If you don’t have the wall space for this Worcester Bosch system boiler and would prefer to hide it away in a kitchen cupboard, it’s worth noting that the Worcester Greenstar 27i and 30i system boilers are both smaller in size (690x390x280mm.) They’re designed to fit in a standard kitchen cupboard, but as we said before, it’s always best to double check with your tape measure first.

Worcester Bosch 12i Warranty

Hometree are Worcester Bosch Accredited Installers and can offer a free 5-year warranty with every boiler installation. If you’d like to double this to 10 years, we can arrange this for a small extra charge.

Worcester Bosch Greenstar 12i System Energy Efficiency

Today all boilers have an ErP rating. This stands for Energy-related Product and is the system used to determine how energy efficient a boiler is. The good news is the Worcester Greenstar 12i system boiler has an A-rated ErP of 94%. So if you’re swapping an old boiler, with a lower ErP, for the Greenstar 12i, you should see a reduction in your energy bills. Not only that but you’ll also be doing your bit for the environment and get a big thumbs-up from us!

Verdict – Is the Worcester Bosch 12i the best boiler for your home?

If you have a small household, with up to 10 radiators and require a system boiler, the Worcester Bosch Greenstar 12i will make a fantastic choice. As well as being able to provide hot water to taps simultaneously, it also has the added benefit of being solar compatible, giving you the opportunity to reduce your carbon footprint, along with your energy costs.

Speaking of energy, it’s very efficient and therefore a sensible choice for those looking to replace an older model. Paired with a smart device, you’ll benefit from increased functionality, which will not only ensure you’re Boiler Plus compliant but could result in lower energy costs too.

Size-wise, it’s not the smallest on the market, but with flexible location options, this shouldn’t take away from the many benefits it has to offer. For more information on the Worcester Bosch 12i, feel free to get in touch with us.

 Worcester Bosch Greenstar 12i System
ErP rating (energy efficiency)A (94%)
Size (HxWxD in mm)710x400x330mm
Heating output (kW)12
Standard warranty (years)5 (extended warranties available)
Other available sizes (kW)9, 15, 18, 21, 24

Which? boiler review

The consumer group Which? review each boiler on the market to find the most (and least) reliable boilers according to a survey completed by thousands of boiler owners. In each review, Which? supply a brand score percentage and star ratings for each category. Take a look at the Worcester Bosch Greenstar 12i System boiler ratings below:

Which? Score 
Efficiency rating★★★★★
Brand reliability★★★★★
Brand customer score★★★★★
Ease of repair★★☆☆☆
Ease of service★★★☆☆
Availability of parts and spares★★★★★
Build quality★★★★★
Engineer recommendation★★★★★
Brand score86%

Boiler manual

Worcester Bosch Greenstar 12i System boiler manual

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