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Worcester Bosch Greenstar 15i System Boiler – Review

Next up, we have the Worcester Bosch 15i, a popular system boiler from the brand’s Greenstar range. Here we’ll provide you with all the information you need to decide whether it’s a good fit for your home.

We’re pretty sure you’ll have heard of Worcester Bosch before but just in case, here’s a little information about the brand behind the Greenstar 15i. Worcester Bosch is a UK boiler manufacturer that has been operating since the early 1960s. Over the years, they’ve gained a reputation for greatness, manufacturing powerful, energy-efficient boilers, to suit all properties. Their biggest competitor is Germany’s Vaillant brand, with both companies owning a large share of the European domestic boiler market.

If you are looking for a reliable system boiler, you can’t go far wrong with a Worcester Bosch. They’re a trusted brand you can count on, and as Worcester Bosch Accredited Installers, Hometree is the top choice for your boiler installation.

Now we’ve got that straight, let’s take a closer look at the Worcester 15i system boiler.

Will the Worcester Bosch 15i System be suitable for my home?

The Worcester Bosch Greenstar 15i is ideal for small to medium-sized houses, as well as flats and bungalows. It has a central heating output of 15kW and can heat up to 10 radiators. If you haven’t already, count up your radiators and see how many you’ve got. It’s the easiest way to determine the boiler output you’ll need.

As the Worcester Greenstar 15i is a system boiler, it will need a cylinder to store the hot water, but it won’t need a loft tank. If you already have a cylinder installed, the Greenstar 15i could be a practical choice. If not, we can help you find a hot water cylinder that is compatible with the Worcester 15i, providing that it’s the best choice for your home.

One of the great things about installing a system boiler is that you can get hot water to multiple taps at the same time. This means if you’re washing the pots in the kitchen sink and someone else in your household is running a bath, you’ll both be able to access hot water without having to compromise on lower pressure. The Worcester Bosch 15i can also be installed as part of a solar heating system for energy and cost savings.

If you have a bigger home with more than 10 radiators, one of the higher output models (18kW, 21kW, 24kW, 27kw or 30kW) from the Greenstar i system range, is likely to suit you more. The two larger outputs are more compact in size and designed to fit inside a standard kitchen cupboard.

For comparison with another brand, take a look at the Vaillant ecoFit Pure 615. This system boiler also has a central heating output of 15kW and is solar compatible like the Worcester Bosch 15i. The key difference is the slightly smaller size, as it’s intended to fit in a standard kitchen cupboard.

Worcester Bosch 15i System Controls

Flip the front flap of the Worcester Bosch Greenstar 15i, and you’ll find a standard display with basic control buttons. There are option keys for increasing and reducing the temperature of your heating and hot water. It’ll also alert you to any faults.

The temperature control functionality makes the Worcester Bosch 15i System boiler compliant with the Boiler Plus regulations, which were introduced back in April 2018. The regulations also set the minimum energy efficiency level boilers must meet.

Another way to ensure compliance and gain greater control over your heating and hot water system is to link your boiler with a smart device. The Worcester Bosch 15i System boiler is compatible with a number of smart thermostats. Here are a few suggestions from our experts:

Bosch EasyControl – Use this smart thermostat with its corresponding mobile app to control your boiler from any location. With options to pre-heat your home and turn off the heating in unused rooms, you can tailor your settings to meet your individual needs. Alternatively, Worcester Bosch also offer the Wave smart thermostat.

Nest and Hive – Two highly sought after smart thermostats that are compatible with the Greenstar 15i. The Nest and Hive both have their own mobile apps, allowing you to gain complete control over your heating system. Want to find out more? Check out our Nest Vs Hive review.

Honeywell Lyric T6 – This is an entry-level smart thermostat that comes with a user-friendly mobile app, flexible scheduling features, and geolocation technology. Don’t want to spend money on a smart thermostat? Choose Hometree to install your Worcester Bosch 15i System Boiler, and we’ll give you the Honeywell Lyric T6 free of charge!

Worcester Bosch Greenstar 15i Size

The Worcester Bosch Greenstar 15i measures 710x400x330mm and is designed for wall-mounted installation. It probably won’t fit inside a standard size kitchen cupboard, so if that’s a key requirement, you’ll perhaps want to look at the Greenstar 27i instead. Despite having a higher output, it’s one of Worcester Bosch’s newer generation boilers, which are smaller and more lightweight in design.

Worcester 15i System Boiler Warranty

All of our Worcester Bosch boiler installations come with a 5-year warranty as standard. If you would like to extend this to 10 years, we can do so, for a small extra charge. Get in touch for more information.

Worcester Bosch 15i System Energy Efficiency

Today it’s important to choose an energy-efficient boiler. The more energy efficient a boiler is, the lower your bills will be. You could also significantly reduce your carbon footprint. It’s a win for you and a win for the environment.

We’re pleased to say the Greenstar 15i has a fantastic ErP (the system used to rate the energy efficiency of boilers) of 94%. This is an A-rating overall and is one of the best you can get.

Verdict – Is the Worcester Bosch 15i System the best boiler for you?

If you are looking for a boiler with a fairly low output that can heat up to 10 radiators, the Worcester Bosch 15i system boiler is definitely one to consider. It’s highly efficient and can be used as part of a solar heating system for lower energy usage and costs.

Combined with a smart thermostat and digital controller, you’ll benefit from being in complete control of the 15i System and have the advantage of being able to tailor it to the exact needs of your household.

We hope you have found our Worcester Greenstar 15i review helpful. If you have any further questions, please don’t hesitate to get in touch with our team of experts.

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

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