Conventional versus Combination Boilers - The Pros and Cons:

A Conventional boiler is purely a heating appliance – there will be an external hot water cylinder, control valves and radiators.

Worcester-Bosch Ri conventional boiler

Why would you want one?

  • More than one hot water outlet can be supplied simultaneously (dependant on a separate storage cylinder)
  • You desire a longer service life for a boiler than 10-12 years.
  • You would prefer to have a stored hot/cold water supply in the house
  • You may have recently invested in a new hot water cylinder/tanks
  • You want an electrical immersion heater as hot water backup in case of boiler failure
  • The water flow rate (sometimes erroneously described as pressure by plumbers) is too low for a combination boiler (but see low water mains pressure solutions as there are solutions available)
  • All conventional boilers are now condensing technology, mandatory in the UK
  • Perceived reliability advantage.


A System Boiler;

Is a conventional boiler (above) with the circulation pump mounted within the boiler casing, most of these are designed to be fitted to a sealed radiator system (in other words, one without a header tank).

They also incorporate some sealed system components, such as an expansion vessel, shown in the ATAG boiler below.

ATAG i32S System Boiler

A Combination boiler contains all the necessary controls and equipment to provide instantaneous hot water and also central heating – apart from radiators and pipe, everything else is in the boiler.  There are now over 7 million households in the UK equipped with Combination boilers.

New for 2019, Worcester Bosch Greenstar 8000

Why would you want one?

  • Convenience. Hot water is always available, 24 hours a day
  • Economy. Only heat the hot water you use.  Ideal if you are at home infrequently.
  • Consecutive hot water demands can be made without running out
  • You don’t require to run two hot water taps simultaneously
  • No water tanks in the roof or hot water cylinders are required.
  • It’s a one box compact solution, ideal for small properties
  • All combination boilers are condensing versions, now mandatory in the UK
  • It offers mains pressure showering without a pump (ideal for flats or loft conversions)

Customer Testimonials

Excellent Work

Excellent work , the workers were very efficient, considerate and tidy. They worked with the least disruption possible for an elderly lady. Any unexpected problem was dealt with safely and professionally. The finished heating is to a high standard. K.T. Kent

Jennie 05/05/2017