When it comes to choosing a new boiler, you need to weigh up the options available to you as well as the requirements that your home has for hot water and heating. Combi boilers are the most efficient boilers out there, but are they always worth upgrading to? Bog Standard Plumbing and Heating discuss this in this blog post...
What exactly are combi boilers?
Combination boilers, sometimes known as combi boilers, are the most prevalent boiler type in the UK today. They function by supplying on-demand hot water directly from the mains without the need for a storage tank. Because a combi boiler distributes hot water at mains pressure, you may take a shower without the need for a separate shower pump. Because all of the components are housed inside one unit and no separate hot water tank is required, these boilers are perfect for houses with limited space. A storage combi boiler is a type of boiler that is suitable for larger households. They operate similarly to a combi boiler, but feature a hot water tank similar to a traditional system, allowing extra hot water to be stored and utilised later.
What are the limitations of a combi boiler?
If your home low flow rates and/or low incoming water pressure, then a combi boiler is not right for you. When delivering hot water to two or more outlets at the same time, hot water flow rates are lowered, so this is a concern if you own a home with two or more showers.
Combi boilers with large hot water capacities might also be inefficient for heating systems. Many variables influence whether you should maintain your current boiler or move to a combi boiler. It all boils down to the system's age, water pressure/internal flow rates, and hot water requirements.
If you have over 3 bathrooms, don't get a combi boiler
Flow rates for combi boilers range from 10 to 25 litres per minute, which is suitable for the vast majority of houses with one or two bathrooms. Even the largest household combi boiler may not be adequate if you have a large home with several bathrooms, are extending bathrooms, or if you and your family take many showers at the same time.
When several hot water outlets, such as two showers, are used at the same time, the hot water flow rate of even the largest boilers is cut in half. We advise opting for a system boiler with an unvented hot water cylinder (if your water pressure is good). Even the most powerful combi boilers would not be able to cope with 3 showers running simultaneously. That's why if your house has more than three bathrooms and a system boiler and a high-performance hot water cylinder, a system boiler and high-performance hot water cylinder may be a better alternative.