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Which Oil Combi Boiler Brand is Best?

Is your boiler starting to give up? Leaving you without hot water and shivering in bed on cold mornings? If you want to say goodbye to cold showers, you need to invest in a new oil combi boiler.

When you’re choosing an oil combi boiler, you have a lot of options. It’s essential to understand which oil combi boiler is best for your needs. Our expert AddHeat team is familiar with all of the major UK brands – we can install any oil combi boiler. We go above to help you get the most out of your boiler so you can keep your home warm, dry, and comfortable all year round.

So, which oil combi boiler is best?

Start by Assessing Your Property

Every property has its own specific needs, with different hot water demands and heating requirements. That’s why it’s so important that you understand precisely what you need before you start looking.

It’s wise to do your research. By assessing your boiler needs in advance, you’ll save money and get the right oil combi boiler for your home or commercial property. That way, you won’t end up with an unnecessarily large boiler, spending more than you need to on the outlay or the running costs.

Similarly, if you end up with an oil combi boiler that’s too small, you’ll have the opposite problem. Your boiler will struggle to meet your hot water and heating needs. You’ll end up cold all the time, and you’ll have to upgrade. That’s a lot of lost time and money, not to mention added stress.

To avoid all of this hassle, have your home inspected by an OFTEC registered heating engineer before you select and purchase your next oil combi boiler.

Most of our clients choose combi boilers because they don’t require a storage tank, cold water tank, or cylinder. Instead, it heats the water you need on-demand, when you need it. You’ll save a ton of space, and always have hot water and heat.

Which Oil Combi Boiler Brand is Best?

There are three leading boiler brands that we suggest, based on their reliability, cost-effectiveness, and overall quality. While there are other high-quality brands out there, we find that our clients rate Grant, Worcester Bosch, and Warmflow, and often request these brands by name.

Grant oil boiler installed in a kitchen
  • Grant – Grant is known throughout the UK for offering the most extensive range of oil boilers available, including some extremely energy efficient models. For instance, the Grant Vortex and VortexBlue offer an energy efficiency of 93.3%!

    When it comes to warranty, Grant doesn’t disappoint. Their boilers come standard with a 5-year warranty when installed by an accredited engineer. Steer clear of cheaper brands that offer little in the way of warranties – they’re just not worth it.

When it comes to selecting the best oil combi boiler, you’re spoiled for choice with Grant. They have an extensive range, so your odds of finding the best oil boiler for your property are high.

  • Worcester Bosch – If you’ve done any boiler research, you already know a lot about Worcester Bosch. This is the most popular oil combi boiler brand in the UK, with a ton of choices to meet your needs.

    Their warranties start at two years, but can reach all the way up to five years – every model is different. To ensure you maximise your warranty, ensure that you have your Worcester Bosch oil combi boiler installed by an officially licensed installer.

    Worcester Bosch offers models in all sizes, capacities, and shapes, so you can find one that fits well in your property without taking up too much space. Their oil boilers are divided into two ranges – the Greenstar Danesmoor and Greenstar Heatslave II.

  • Warmflow – Known for efficient oil combi boilers, Warmflow offers only AA-rated boilers in the UK and Ireland. That means that they’re rated 30% more efficient for hot water, which will save you money and help the environment.


Warmflow uses branded components from trusted brands in every one of their boilers, but should you need your warranty, they have you covered. If you have your boiler installed by an approved installer, you’ll receive an “out-of-the-box” 5-year warranty.

Check out the U-series (sleek and stylish), K-series (an external oil boiler), and B-series, ideal for garages and boiler houses.

So, which should you choose? Grant, Worcester Bosch, or Warmflow?
It’s impossible to give a definitive answer to this question. The answer depends on your available space, hot water consumption, and brand loyalty. It’s worth speaking to a professional boiler expert – they’ll consider your needs, and help you make the best choice for your property.

When it comes to warranty, Grant and Warmflow do have an advantage with their 5-year warranties, so that might be something to consider. No matter what, always ensure that you work with an accredited installation company to install your boilers.

AddHeat Can Help You with Your Boiler Questions
Now that you know more about the leading oil combi boiler brands in the UK, you can choose which is best for your needs. Do you have any questions? Our expert AddHeat team is always on hand to help you choose the best boiler and install it in your home or commercial property.

We’re expert approved installers for Worcester Bosch and Grant boilers, but we can install and advise on absolutely any brand.

Call or email us today and we can answer all of your questions.

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Our Accreditations

To ensure our customers receive a high standard of workmanship and professionalism,
our company is accredited and monitored by several trade and industry bodies.
We are:
- Gas Safe Registered
- OFTEC Registered
- Worcester Accredited Installers
- Grant Approved Oil Boiler Installers.