Best Oil Boilers 2023 Re January 20, 2023

Best Oil Boilers 2023

Oil boiler tank

According to data collected in May 2020, 85% of UK households use gas-fired boilers to heat up their homes and provide hot water. However, around four million households aren’t connected to the Gas Grid. Instead, they rely on a range of alternative heating fuels such as LPG, oil, solid fuels, electricity or solar to make their homes toasty!

If you’re one of these four million, then you might want to look at the right options to heat up your home, especially if your old heating system is ready to retire or you’re planning to renovate your home. 

Here, we’ll take a look at the best oil boilers out there to help you choose the right oil boiler for your home (and wallet!). But first, you might want to find out what type of boiler you have, before you take the plunge.

What is an oil boiler?

While gas boilers are currently the dominant source of heat and hot water for UK households, it’s been estimated that 1.1 million homes currently run on oil heating. Oil heating is also referred to as a ‘wet’ system because it burns fluid (oil). The oil fuel itself is more affordable than electricity and LPG, therefore, it’s a popular alternative for suburban and rural homes.

How does an oil boiler work?

You’ll find that an oil boiler works in a similar way to a gas boiler. 

In summary, the water is supplied directly from the mains (if you have a combi or system boiler) or from a cold-water tank kept in the attic (if you have a conventional boiler.)

The fuel, in this case oil, gets ignited in the combustion chamber and a heat exchanger warms up the cold water. The heated water is then used in your radiators, to provide heating, and it also runs through the taps and showers to provide your home with hot water.

The main difference between a gas boiler and an oil boiler is the type of fuel they use and the way the fuel is stored. A gas boiler gets its fuel from the Gas Grid, while an oil boiler comes with an oil tank that is stored on your property and there are certain installation regulations that need to be followed.

The tank is usually refilled when it reaches a quarter full to ensure that you don’t run out of heating oil and to avoid the impurities running through the heating system.

Oil boilers' pros and cons

  • If you’re not connected to the Gas Grid, an oil boiler can be an excellent option as the fuel is affordable and accessible.
  • The oil boiler and tank are located outside of the house. This can free up space in your home.
  • Due to your boiler and the tank located outside of your house, servicing the boiler is less disruptive to your daily life as your boiler can be fixed, replaced and refuelled without your home being turned into a workshop! 
  • Although carbon monoxide poisoning has become much rarer due to improved safety measures, there is still a chance of a leak causing symptoms. Having your boiler located outside eliminates this risk.
  • Having an oil boiler located outside means that should the boiler leak or malfunction, there is less chance of it causing damage to your property, compared to a gas combi boiler located in your airing cupboard leaking.
  • If your oil boiler is located in an outbuilding, garage or shed it will serve to partially heat the building from heat loss.
  • If you have limited outdoor space for a large oil tank then perhaps an oil boiler isn’t the right option for you. The tank also needs to be easily accessible for refilling otherwise you may have to install an expensive pipe run to get to the tank.
  • Oil prices can fluctuate depending on the market. This is also true for other fuel sources but oil is more volatile as there are more factors that affect the price and there is no official regulation.
  • The fuel supply needs to be physically delivered. This means there is the chance of delays, human error in an order, traffic or forgetting to order in time. Newer oil tanks have sensors that can automatically place an order when you get down to a certain level.
  • Having an oil boiler installed for the first time is more expensive than installing a gas boiler.
  • Oil boilers are twice as bad for the environment as gas boilers in terms of carbon dioxide production.
  • An oil storage tank can be an eyesore if it isn’t placed underground or tucked out of the way. It will ruin your view when you’re sitting in your hot tube! 
  • The flow rate of an oil boiler is usually lower than that of a gas boiler.
  • The boiler and tank are located outside of the house, which means there is damage that comes with weather exposure; cold, frost and rain. This can cause components to rust or malfunction.

*If you’d like to know more about the pros and cons of having an oil boiler, check out our guide.

Oil boiler installation costs

Whether you choose a local company, energy supplier or an online company like WarmZilla to install your boiler, you should always check that the installer is OFTEC (Oil Firing Technical Association) registered. This is the oil certification equivalent to Gas Safe registered for gas boiler installations.

The cost of installing a new oil boiler varies depending on a range of factors that determine the complexity of the job. On average, oil boiler installation can cost between £2,500 – £4,500.

You’ll also need to factor in the cost of the boiler, oil tank and all the other appliances as well.

Oil boiler running costs

Domestic oil prices are tied to the price of crude oil, so they can fluctuate with demand, availability and even political situations (such as the Gas Crisis we witnessed in October 2021). 

Oil prices are also affected by demand, so the prices will increase during winter. 

In terms of how oil prices compare against other fuel types – it’s more expensive than gas (per kWh) and LPG but cheaper than other alternative fuel sources on the market such as biomass and electric.

Based on heating a standard 3-bedroom home, electricity is the most expensive alternative fuel source at £1500 per year, followed by oil at £1400 compared with gas at £700 – £1400.

An oil boiler can be combined with solar thermal heating or solid fuel to lower the cost. However, if your home doesn’t run on solar power, we advise going for the highest SEDBUK efficiency rating you can afford when buying a new oil boiler. This will ensure that your boiler is energy efficient and will be kinder to the environment and your wallet too!

Oil boiler annual service costs

The cost of having your boiler serviced varies depending on many factors such as location, the age of the boiler and the condition it is in. Generally speaking, the annual service of an oil boiler could cost between £80 – £180.

The environmental impact of oil boilers

Regulations introduced in 2007 meant that all condensing oil boilers must have an energy efficiency rating of 86%+. Nowadays, most modern oil boilers attain an energy efficiency rating of 92%+.

On the other hand, oil boilers are worse for the environment than gas boilers, because burning oil produces twice as much carbon as gas. 

If you’re looking for environmentally-friendly heating solutions, you might want to have a look at heat pumps, hydrogen boilers, microwave boilers and electric boilers. Each has its own advantages and disadvantages, so read our overview here.

The best oil boilers in 2022

If you’re in the market for an oil boiler, you might want to read this blog. It gives you an idea of when you’ll need to replace your oil boiler.

Vokera boilers Alpha boilers

1. Worcester Bosch

Worcester Bosch is the leading boiler manufacturer in the gas boiler market, and that includes the oil boiler market too. To sum it up, Worcester Bosch offers an extensive range of boilers with a range of different fuels and is suitable for properties of all sizes.

Worcester Bosch is known as being the “Rolls-Royce of the heating industry”. It is at the premium-end, but you’ll get excellent build quality combined with elegant design. It’s a brand you can rely on.

Surely it’s no surprise that Worcester Bosch came first according to Which? Best Boiler Brand survey 2021.

During the survey, 8,001 members of the public who’ve bought a boiler in the past six years were asked to rate their Worcester Bosch oil boilers based on reliability and how likely they were to recommend Worcester Bosch to friends and family.

Which? asked 153 Which? Trusted Traders how they felt about the build quality, the ease of fixing and servicing Worcester Bosch boilers and how easy it is to get hold of boiler spare parts.

Here’s the score: 

Worcester Bosch overall score


Reliability Score

5 star

Brand customer score

5 star

Brand engineer score

4 star

Worcester Bosch prides itself on its excellent customer service. It has a TrustPilot score of 4.6/5.

Worcester Bosch oil boiler warranty

Worcester Bosch oil boiler warranty is between 2-7 years depending on the boiler model.

Worcester Bosch oil boiler range

No matter what your house size is, Worcester Bosch has got you covered. The Worcester Bosch oil boiler comes in the following models;

  • Greenstar Danesmoor
  • Greenstar Heatslave II (best selling model)
  • Greenstar Utility

Available as a combi, system and regular oil boiler.

Worcester Bosch oil boiler cost

The cost varies depending on the model and oil boiler type. It could start from £2,600 for an oil combi boiler, £1,860 for an oil system boiler and £1,700 for an oil conventional boiler**. These boiler prices don’t include installation though, so be sure to factor that in.

2. Grant

Grant has over four decades of boiler manufacturing experience. They’re known for quality and reliability, offering a range of boilers that can be easily installed and maintained.

The entire Grant oil boiler range was awarded a Which? Best Buy Awards in 2017, 2018 and 2019. Which? Recognises Grant boilers as one of the best oil boiler brands in the market and described it as a “reliable” brand.

Grant’s rating: 

Grant overall score


Reliability Score

4 star

Brand customer score

3 star

Brand engineer score

4 star

Grant has an astonishing score on TrustPilot (4.5), which indicates that their customer service is brilliant, and their customers are happy with the product.

Grant oil boiler warranty

Nothing says that the boiler is built to last more than a long warranty and that’s what you get when you invest in a Grant boiler. 

The boiler range warranty is 5 years. (10-year guarantee when installed by a G1 Installer, if you bought a Vortex Blue) – your driving license will expire before your boiler warranty does!

Grant oil boiler range

Grant designed a wide range of products which means you’re guaranteed to find the right one for your home. 

The range includes; 

  • VortexBlue (best selling model) 
  • Vortex Pro 
  • Vortex Eco

The award-winning Vortex and VortexBlue oil-fired condensing boilers are available in internal, external, combination, boiler house and wall-hung models, all of which are endorsed by the Energy Saving Trust.

Grant oil boiler cost

To give you a rough idea, the Grant combi oil boiler prices start from £2,220, while the system oil boiler range starts from £1,610, and Grant regular boilers price range starts at £1,240.**

3. WarmFlow

WarmFlow is the most efficient oil boiler. Their combi oil boiler saves up to 5ltrs of fuel per week because it is the only AA rated oil combi boiler in the market (no other brand has an AA rated combi oil boiler). Sounds too good to be true!

WarmFlow has over five decades of boiler manufacturing experience. It uses a unique patented stainless steel heat exchanger alongside the latest Riello burner.

Although WarmFlow isn’t featured in the Which? Best Boiler survey, it doesn’t affect its reliability. It has a ​​4.3 TrustPilot score which means that their customers are happy with the boilers and customer service.

WarmFlow oil boiler warranty

Warmflow offers a 5-year warranty for both parts and labours if installed by a Warmflow Connect approved installer.

WarmFlow oil boiler range

The WarmFlow Agentis oil boiler comes in combi, system and regular oil boiler range. This includes internal and external boilers. It also includes boiler houses and professional boiler systems.

Additionally, they also produce a professional range which is the only oil boiler to include a factory fitted magnetic filter saving installation time and money.

WarmFlow oil boiler cost

WarmFlow oil boiler price range starts from £1,970 for an oil combi boiler, £1,370 for an oil system boiler and from £1,170 for regular oil boilers.**

4. Hounsfield Boilers

Hounsfield Boilers are a niche, high quality, independent brand that has been established since 2008 and plumbers choose us for domestic oil-fired boilers.

They meet and exceed the latest European Boiler Efficiency Regulations and safety standards. With the introduction of the “Hounsfield – Elco burner” Hounsfield Boilers are future-proofed and ready for HVO fuel (hydrated vegetable oil) a fuel with CO2 emissions 91% less than Kerosene.

Make sure your boiler ticks all the boxes…

  • 5 Year No Quibble Warranty
  • Modern efficient Heat Exchanger design
  • Life-long Flexible Oil Line
  • Paper element Oil Filter and Fire Valve kits included
  • Fully Insulated Casing for whisper-quiet operation
  • Bespoke Elco Burner is HVO ready
  • Ultra-safe controls and Visible Neons
  • Plug and Play Electrics
  • Versatile Flue Options – One system fits all
  • Single Oil Pipe Supply – no need for Tigerloop

Hounsfield Boiler Products

Their boiler range starts from £1,595 RRP (inc.VAT) and include an oil filter kit and fire valve as standard. 

Hounsfield Boiler Models

  • 12/19kw Tuscan Kitchen & External models including a wall-mounted version for both indoors and outside
  • 20/25kw Tuscan Kitchen & External models
  • 26/30kw Tuscan Kitchen Model
  • 50/70 & 75/95 Tuscan non-condensing internal kitchen model boilers

Hounsfield Boiler Warranty

Warranty is an important consideration when choosing a new boiler. Hounsfield is invested in high-quality materials and the best engineering practice – they have just three terms and conditions of the warranty.

  • The warranty must be registered with Hounsfield Boilers.
  • The boiler must be serviced every year.
  • Warranty work must be authorised by Hounsfield Boilers.

For heat exchanger replacement after the warranty period, a discounted pricing structure based on age is applied, the full price is only chargeable in year eleven.

Hounsfield Boiler Cost

Hounsfield Boiler prices start from £1,595 RRP (inc.VAT) and include an oil filter kit and fire valve as standard.

Home heating oil provider

If you’d like to buy oil for your boiler, you can check out BoilerJuice. They are the UK’s number 1 home heating oil provider. They have over 17 years of experience and they’re here to help you find the best heating oil price in your area, quickly and easily.

The future of oil boilers

The UK has pledged to reduce carbon emissions to zero by 2050 and become a carbon-neutral nation. With one-third of the UK’s CO2 emissions coming from heating our homes, it’s clear that to achieve the carbon-neutral target, change is coming to the heating industry.

In the Heat and Buildings Strategy, the government has set out its intention to phase out all fossil fuel-based heating systems, including oil.

To be more specific, the plan will start by phasing out fossil fuel systems in homes that aren’t connected to the Gas Grid. ​​The Government’s ambition is to set an end to the installation of fossil fuel heating in homes off the gas grid from 2026 (and non-domestic buildings from 2024). It’s worth noting that WarmZilla does not sell oil boilers.

It’s also not hard to see the reasons why. A report published by the IEA (International Energy Agency) suggested that heating homes with oil or gas is responsible for about 20% of total carbon dioxide emissions in the UK and the US. (source: inews).

To tackle this issue, the UK Government has proposed the following plan: 

  • An end to the installation of new fossil fuel heating in homes off the gas grid from 2026.
  • A ‘heat pump first’ approach to replacement heating systems from 2026.
  • Introducing high-performing replacement heating systems where heat pumps cannot reasonably practicably be installed.

There are concerns currently though around the affordability of heat pumps. However, as part of the Heat and Buildings Strategy, the UK Government is setting an ambition of working with industry to reduce upfront costs of installing a heat pump by 25-50% by 2025 and to achieve cost parity between heat pumps and gas boilers by 2030.

At WarmZilla we want to make it super easy for you if you decide to get a new gas boiler. This is why you can get a quote online within minutes. Whether you opt to go for a flexible finance package or pay in full too, there are even more ways for you to get a brand new boiler at an affordable price.

*Average boiler prices were taken from an online heating supplier 
** Prices correct at time of blog publication (1.12.21)
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