Best Oil Boilers in 2019


To help your search for a brand new oil boiler, we’ve compared the Top 5 Oil Boiler Manufacturers in 2019 so that you know which manufacturer to go with.

While less commonly installed than gas boilers, oil fired boilers need to deliver exactly the same benefits to your home. The oil boiler you choose needs to measure up in terms of energy efficiency, warranty and performance. But, inevitably, you also need to balance this with your budget.


 


Best oil boilers

In this article we’re going to compare 5 of the best oil boilers on the market to help you find the right one for your home. The best oil boilers include:

  • Worcester Bosch Greenstar Heatslave II
  • Grant VortexBlue
  • Mistral Combi Standard
  • Firebird Envirogreen Combi
  • Warmflow Utility HE Combi

Worcester Bosch Greenstar Heatslave II

Best Oil Boilers: Worcester Bosch Greenstar Heatslave II
The Worcester Bosch Greenstar Heatslave II is a condensing combi oil boiler that can be installed externally, so it won’t take up any valuable space around the home. As a combi boiler, Heatslave II boilers provide central heating and hot water on demand, with an impressive flow rate of 15 litres per minute.

The range includes oil boilers with output ratings of 18 kW, 25 kW and 32 kW, making it easier to find a suitably powerful boiler for your property. Each of these boilers is highly efficient, which will help to keep your energy bills down and if you choose to have an internal model installed then the compact dimensions allow it to sit between kitchen units.

The Greenstar Heatslave II 12/18 has even been endorsed by the Energy Saving Trust.

Worcester Bosch Greenstar Heatslave II
Model Output Ratings Dimensions (HxWxD) Efficiency ErP Rating
Greenstar Heatslave II 12/18 18 kW 855 x 520 x 600mm 90% Heat: A
Hot water: B
Greenstar Heatslave II 18/25 25 kW 855 x 520 x 600mm 90% Heat: A
Hot water: B
Greenstar Heatslave II 25/32 32 kW 855 x 520 x 600mm 90% Heat: A
Hot water: B

All of the above are designed for internal installation but external models of the Worcester Bosch Greenstar Heatslave II range are also available.

Grant VortexBlue

Best Oil Boilers: Grant VortexBlue
The Grant VortexBlue is an internal combi oil boiler, which means that it’s capable of providing central heating and domestic hot water on demand without the need for any external tanks or cylinders. An efficiency rating of 91.7% makes this an A-rated unit for heat, while it also has a B for hot water.

Availble in a range of outputs, including 21 kW, 26 kW and 36 kW, gives you a great chance of finding a suitable powerful boiler for your home. As standard, the Grant Vortex Blue is available with a 2 year warranty.

Grant VortexBlue
Model Output Ratings Dimensions (HxWxD) Efficiency ErP Rating
VortexBlue Internal 21 21 kW 860 x 470 x 603mm 90.81% Heat: A
Hot water: B
VortexBlue Internal 26 26 kW 860 x 470 x 603mm 91.71% Heat: A
Hot water: B
VortexBlue Internal 36 36 kW 860 x 470 x 603mm 94.56% Heat: A
Hot water: B

All Grant VortexBlue boilers are also available as system boilers as well as for external installation.

Mistral Combi Standard

The Mistral Combi Standard boiler range includes 4 highly efficient condensing combi boilers that are available for indoor or outdoor installation. With 4 models available (CC1, CC2, CC3 and CC4), each with a different output rating between 15 kW and 41 kW, there’s likely to be a unit to suit the heating and hot water demands of almost any property.

Manufacturer, Mistral, even claim that their Combi Standard range can produce almost twice as much hot water as any other oil combi boiler on the market.

Mistral Combi Standard
Model Output Rating Dimensions (HxWxD) Efficiency ErP Rating
CC1 15 – 20 865 x 600 x 600mm 92% Heat: A
CC2 20 – 26 865 x 600 x 600mm 92% Heat: A
CC3 26 – 35 865 x 600 x 600mm 92% Heat: A
CC4 35 – 41 865 x 600 x 600mm 92% Heat: A

Firebird Envirogreen

Firebird were the first brand in the UK to produce a SEDBUK Band A rated Combi boiler and the UK’s first Blue Flame oil fired condensing boiler. Blue flame technology perfects the combustion process and lessens the carbon emissions of the boiler.

The Firebird Envirogreen range of condensing combi oil boilers are available as both standard and slimline models for installation in a utility room or kitchen. A range of output ratings including a 20 kW, 26 kW and 35 kW models are all available with each boasting high performance low NOx and Blue Flame burner options.

Firebird Envirogreen Combi
Model Output Ratings (kW) Dimensions (HxWxD) Efficiency ErP Rating
Envirogreen Combi HE20 20 kW 845 x 595 x 614mm 93% Heat: A
Hot water: B
Envirogreen Combi HE26 26 kW 845 x 595 x 614mm 93% Heat: A
Hot water: B
Envirogreen Combi HE35 35 kW 845 x 595 x 614mm 93% Heat: A
Hot water: B

Warmflow Utility HE Combi

Best Oil Boilers: Warmflow Utility HE
Founded in 1970, Warmflow is Northern Ireland’s leading manufacturer of award winning, oil fired boilers with over 45 years experience heating homes across UK & Ireland. Their award winning range includes oil fired boilers, including the UK & Ireland’s first double A rated combi boiler.

The Warmflow Utility HE range of oil boilers are highly efficient condensing regular boilers that includes models with a range of output ratings from 21-35 kW, helping to make it easier to find a suitable unit for your home.

As regular boilers, Utility HE units need to be installed as part of a heating system alongside a hot water cylinder, cold water storage tank as well as a feed and expansion tank. Regular boilers are best suited to larger properties with higher demands for heating and hot water.

Warmflow Utility HE Combi
Model Output Rating Dimensions (HxWxD) Efficiency ErP Rating
UC70HEE 21 kW 865 x 595 x 600mm 90.7% Heat: A
Hot water: A
UC90HEE 26 kW 865 x 595 x 600mm 90.8% Heat: A
Hot water: A
UC120HEE 35 kW 865 x 595 x 600mm 90.7% Heat: A
Hot water: A

 


Comparing the best oil boilers

Comparing the best oil boilers on the market will help you to find the most suitable oil boiler for your home. We’ve compared some of the must know information about each of the best oil boiler ranges, including:

  • Efficiency
  • Warranty
  • Potential cost

Efficiency

In terms of energy efficiency there is very little daylight between any of the best oil boilers, with each range having an ErP A-rating, which means that they’re at least 89% efficient.

In financial terms this means that for every £1 you spend on heating your home, only 11p is spent on wasted energy. When you consider that some older boilers offer as little as 70% efficiency, and therefore waste 30p of every £1, this is a considerable saving over a year.

Warranty

When comparing manufacturer warranties it’s important to check the smallprint. Many advertise lengthy ‘guarantees’ but with strict terms and conditions applied which, if you don’t meet, could make them meaningless. Also, while each boiler includes a ‘standard’ warranty’ it may also be possible to purchase a longer or more comprehensive guarantee.

Grant and Worcester Bosch offer longer 10 year guarantees on some of their models, but these will be dependent on the installation being carried out by an installer who they’ve accredited themselves and meeting specific requirements.

Best Oil Boiler Range Warranty
Worcester Bosch Heatslave II 2 years (can be upgraded to 5 years)
Grant VortexBlue 2 years
Mistral Combi Standard 2 years parts / 5 years heat exchanger
Firebird Envirogreen 2 years
Warmflow Utility HE 5 years parts and labour with 7 years on the heat exchanger

All manufacturers will stipulate that the boiler must be installed by an engineer who is qualified and / or registered with OFTEC (Oil Firing Technical Association). This is a standard requirement and something that’s advisable regardless of warranty; after all, having a boiler installed by an unqualified person presents a significant safety risk. Assuming that this is the case and that you register your guarantee within a specified period (usually 30 days). The vast majority of manufacturer guarantees will only remain valid if your boiler is serviced every 12 months by an accredited installer.

You can find out more about each oil boiler manufacturer’s warranty here:

Potential cost

One of the most influential factors in your decision is going to be the price of the oil boiler.

Warmflow sit at the lower end of the scale, with prices starting at £1,175 (on average), while Worcester Bosch Heatslave II prices can begin at over £2,000. Mistral prices begin at around £1,900, but the company doesn’t offer much more in terms of warranty than the Warmflow or Firebird. Grant and Worcester are the pricier options starting at £2,100 at a minimum, but their warranties and service plans are more comprehensive.

Best Oil Boiler Range Potential Cost
Worcester Bosch Heatslave II £2,190 – £2,425
Grant VortexBlue £1,335 – £2,665
Mistral Combi Standard £1,990 – £2,700
Firebird Envirogreen Combi £1,800 – £2,525
Warmflow Utility HE £1,175 – £1,795

These are guide prices for a like-for-like oil boiler replacement. Installation costs will also need to be taken into account.

Installation costs will vary depending on the size of the boiler, the complexity of the installation, whether it’s an internal or external oil boiler and, ultimately, based on the prices charged by the installer you hire.

To ensure you’re getting the most competitive price, we highly recommend comparing quotes from 2-3 fully-qualified engineers, these can be both national companies and local independents. By simply completing our online enquiry form, you can get free quotes today from up to 3 reputable installers in your area.

Which is the best oil boiler?

Best Oil Boilers: Worcester Bosch Greenstar Heatslave II
When it comes to performance, warranty and reliability, the front-runners in terms of both homeowner and installer recommendations are the Worcester Bosch Greenstar Heatslave II and Grant VortexBlue ranges of oil boiler.

While they might be amongst the most costly oil boilers, your ultimate decision needs to be based on the best long term investment for your home. A new oil boiler should last between 8-12 years and the most efficient models will save you money on heating bills.

So, if possible, it’s not a choice you should be making based on the cheapest price. Obviously, we all have a budget to consider, but it’s important to make sure you’re getting the best warranty and efficiency for your money.

Winner: Worcester Bosch Greenstar Heatslave II
 


 


REMEMBER: Professional installers will have their own experiences of each brand from past installations and customer feedback so always get multiple quotes. Some installers receive incentives to install a certain brand so keep in mind that you might not be getting impartial advice. However, if the installer is specially trained to install a brand it could mean that you receive an extended manufacturer warranty.