If you live in one of the four million properties in the UK that are not connected to the national grid, then you’ve probably considered installing an oil boiler. LPG and electricity also offer viable alternatives to gas, but it’s hard to beat the cost and efficiency of an oil boiler.
When it comes to oil, Worcester Bosch is the king of boiler brands. This article delves into what’s on offer and compares the different types and models to help you find the right oil boiler for your home.
What is an oil boiler?
An oil boiler works precisely like a gas boiler, but the fuel (oil) is stored separately. Instead of gas being pumped directly into the system via a mains-connected pipe, the oil is delivered to the property and stored in a separate tank outside. This makes it ideal for remote properties without access to a natural gas pipeline, i.e., off-grid.
Different types of oil boilers
Like their gas counterparts, there are three types of oil boilers: Combi, system, and regular.
Combi boilers
Combi boilers are suitable for small to medium-sized homes with one or two bathrooms and a low demand for hot water. As the name implies, they combine two tasks: managing central heating and providing hot water. The water is heated as required, so there’s no need for a water cylinder.
System boilers
System boilers can meet a higher demand for hot water and are suitable for medium to large homes with one or two bathrooms. They draw cold water directly from the mains supply, heat it, and store it in a hot water cylinder until needed. The boiler is connected directly to the radiators and stores hot water in a separate cylinder.
Regular boiler
A regular (conventional) boiler is a step up from a system boiler capable of simultaneously providing hot water to several taps. Suitable for large and older properties, it requires a gravity-fed cold water tank (typically stored in the loft or attic) and a hot water cylinder.
Read more: Combi boilers vs system boilers – which is right for your home?
Overview: Worcester Bosch oil boilers
The Worcester Bosch range of oil boilers includes various types and sizes, including combi, system and regular boilers in multiple sizes.
| Model | Greenstar Heatslave II | Greenstar Danesmoor | Greenstar Utility Regular |
| Type | Combi | System, regular | Regular |
| Suitable for | Small to medium-sized homes | Medium to large homes | Large homes |
| Internal/external | Internal and external options | Internal and external options | Internal |
| Output (kW) | 12-18 kW 18-25 kW 25-32 kW | 12-18 kW 18-25 kW 25-32 kW | 32-50 kW 50-70 kW |
| Energy efficiency | A-rated | A-rated | A-rated |
| Solar compatible | Yes | Yes | Yes |
Worcester Bosch oil boilers come with several features as standard across the range. Bosch is well known for offering extended manufacturer’s guarantees, which is why it’s no surprise that almost all of the oil boilers above come with a 7-year warranty (conditions apply, which you can find on the Bosch website).
The Greenstar range of oil boilers also boasts:
- Quiet operation
- Hidden control panel (perfect for anyone with kids)
- A-rated energy efficiency for maximum cost savings on your fuel bill
- Compatibility with optional controls
Let’s look at the models on offer in more detail.
Greenstar Heatslave II
The Worcester Bosch Heatslave II is a popular oil combi boiler that can be fitted inside or out.
The external Heatslave II is powder-coated in a frost-resistant green paint to withstand the cold British weather and blend in with its surroundings. In contrast, the internal boiler is small enough to fit under a kitchen worktop (though the worktop must be removable).
Both are available in three power outputs (12/18, 18-25, and 25-32 kW) to suit different-sized homes.
Greenstar Danemsoor
The Danesmoor is part of the Greenstar range of Worcester Bosch oil boilers. It comes in various types (internal/external, system/regular) and several outputs to suit different-sized properties:
- System: Greenstar Danesmoor External System
- System: Greenstar Danesmoor System Utility
- Regular: Greenstar Danesmoor External
- Regular: Greenstar Danemsoor Utility
The internal Danesmoor boiler is designed for a kitchen or utility room, while the external boiler is housed in the same robust, frost-resistant cabinet as the Heatslave.
The main difference between the Danesmoor and Heatslave II is capacity. The Danesmore is suited to medium-large homes with more than one bathroom. It can simultaneously provide hot water to multiple taps and/or showers, but to enjoy that, you’ll need to find room to house a hot water cylinder, a cold water storage tank, and a third tank to maintain the water level of the central heating system.
This requirement for extra space makes the Danesmoor better suited to larger properties.
Greenstar Utility regular
The Greenstar Utility regular boiler is explicitly designed for large domestic and light commercial properties. It fits comfortably in a utility or boiler room (don’t forget room for the hot water cylinder, storage tank, and overfill).
With the largest capacity of all the Worcester Bosch oil boilers, it’s able to meet high demand for hot water and heating.
How much does an oil boiler cost?
Depending on its type and size, you can expect to pay between £1,000 and £5,000 for a new oil boiler (excluding installation).
The price to fit an oil boiler is determined by the complexity of the installation, where you are in the country, and whether you need additional parts (think pipework and radiators). You might also want extras like smart controls or thermostatic radiator valves (TRVs).
Oil is slightly more expensive to buy than gas but cheaper than electricity or LPG. However, being off-grid gives you much more flexibility. You can buy oil when it drops in price and then store it, allowing you to take advantage of changes in the market.
The final word on Worcester Bosch oil boilers
Picking the perfect oil boiler is determined by the size of your property, its age, and how many people live there. The best way to gauge what’s right for your home is to ask an Oftec-approved heating engineer. They’ll assess your property to help you choose the most efficient oil boiler for your budget.
Whatever boiler you choose, you’re in good hands with Worcester Bosch and approved Bosch installers Arton Heating.
If you found this article helpful, you might also like: Alternatives to gas boilers: What are your options?
