Choosing the right combi boiler will not just help you save a lot of money but will also ensure you keep your home warm all year round. It would help if you considered all the factors associated with the functionality of the boilers before choosing one. As such, the answer to what is the best combi boiler will differ for every person.


The size of a combi boiler is shown by its capacity, which is measured in kW. Most companies categorize their combi boilers according to their power output, and that should be one of the factors that guide you when you’re searching for a suitable boiler. In most cases, small apartments or flats do well with combi sizes that range between 24 kW to 27 kW.

However, if your home has multiple bathrooms and is larger with 3 or 4 bedrooms, a combi boiler between 28 kW and 34 kW should be enough to cater to our heating needs. A larger sized boiler of 35 kW will serve you well if you have a bigger house. It’s important to note that combi boilers don’t work well when two bathrooms are being used simultaneously. Consider having a system boiler that has an unvented cylinder if you have multiple family members likely to take a shower at the same time. It’s also important to note that the bigger the boiler size, the better the water flow will be.


Combi boilers are generally more efficient, but you should still make sure the one you’re investing in will help you save energy. They should be able to heat your water as well as the rest of your house to ensure you don’t rely on other heating sources. Check the energy ratings to ensure it falls within your regular usage.


Different combi boiler manufacturers issue different warranties, ranging from 5 years to 10 years. The longer the warranty, the more value you’ll get. Longer warranties also show that the manufacturer has faith in their product, which shows you that the combi boiler is a quality investment.

Reviews and customer service

A combi boiler that has all the above features but has more negative reviews than positive will most likely fail you. Always check the experience of previous buyers to ensure the product is worth spending money on. Brands that deliver great customer service are also likely to give you support when you need help with your combi boiler.

Some of the best combi boilers you can consider buying right now are:

  • Worcester combi boilers: they come in different sizes and energy ratings, which makes it easier to choose an ideal one. They also have 10-year warranties.
  • Vaillant combi boilers: the brand has a good reputation as shows by great customer reviews. The combi boilers are premium, and the brand offers good warranties. They come at higher costs than other brands.
  • Viessmann combi boilers: these also have 10-year warranties with different output sizes. You will get a lot of extra support when you buy any combi boiler from this brand.

All these brands have several boiler units you can choose from according to your budget or needs. Check the boiler specifications to ensure you end up with the right fit.

What Combi Boiler Should I Get