Which type of boiler is right for my property?

The Boiler Guy in Northampton

We all need heating in our homes and there are a few different options to consider, but often we get asked which one is best. There is no single correct answer to this, as it depends on many factors. In order to help you decide, please consider the information in this post. If you still need some advice afterwards, no problem, just give us a call.

System Boilers

system boiler directly heats your central heating system and produces hot water for a storage cylinder. This type of boiler works like a regular conventional boiler, in that it needs to store hot water. Unlike regular boilers they take their water supply directly from the mains.

The majority of components needed to generate heating and hot water, is built directly into the boiler. The only external part required is a cylinder or tank that stores hot water.


  • Simple to install
  • Great for hot water in property with multiple showers / baths
  • Strong water pressure
  • No need for water storage tank in loft
  • Economical and Efficient
  • Compatible with Solar Power


  • Can take up more space compared to combi boilers
  • Tanks need to be well insulated
  • How water tank size dictates how much water is available to household
  • Hot water is not instant
Combi Boilers

A combi (or combination) boiler is a popular choice in UK homes as it’s efficient, economical and delivers instant hot water on demand. They only heat the water you need, when you need it. This is perfect for many households but not suitable for larger houses, where multiple showers or baths are used at the same times. Water is instant but the volume of water available is much lower compared to water heated and stored in a tank.

Combi boilers remain on a constant standby and are connected to the mains water supply. When water is called (tap or shower turned on), the boiler heats the water through a heat exchanger. This provides instant hot water any time of day. An expansion tank within the boiler sends hot water to radiators.

Combi Boilers Northampton Diagram


  • Instant hot water heated on demand
  • Space saving as no need for water wank or hot water cylinder. You don’t need a cold water tank or hot water cylinder, so you save space
  • Ideal for a smaller house or flat
  • Easier and Faster to install
  • No risk of leaks from lofts
  • Less pipework needed


  • Limited volume of hot water
  • Multiple showers / taps used at the same time can reduce flow (dependant on mains pressure)

Regular Boilers / Conventional Boilers

Regular boilers, also known as open vent boilers, provide central heating and hot water through a hot water storage cylinder, often found in an airing cupboard. In addition a cold water tank is usually found in the loft. This type of boiler is perfect for larger homes with multiple bathrooms, as they can provide a lot of hot water at once.

This is the oldest boiler type available on the market but have really advanced over the years to offer increased performance, reliability and efficiency.

Cold water from the mains is supplied to the water storage tank in the loft, which is then sent to a hot water cylinder, where it’s heated and stored. This water can then be used for taps and showers as required. The feed and expansion tank is there to maintain the water level as water expands when it’s heated.

This type of system often means water pressure in taps and showers is ‘gravity fed’ and sometimes pumps are needed to increase pressure in showers.

Regular Boiler Diagram Northampton


  • Ideal for homes with a large hot water demand (multiple baths and showers)
  • Much easier to replace boiler and use existing tanks compared to switching to alternative type of system
  • Hot water available if boiler breaks down through electric immersion heater


  • Takes up lots of room e.g large tank in loft and hot water cylinder
  • Risk of flooding in loft
  • No hot water on demand, it takes time for hot water to arrive at taps


As you can see, there are pro’s and con’s for all types of boiler. The right type of boiler for you depends on the size of the property, the amount of showers and bathrooms and how many people are likely to use water at the same time. We hope this helps you make the right decision and if you need any help, get in touch as we will be happy to give you the right advise.

If you would like a quote, fill in our interactive boiler enquiry form which will guide you towards the best boiler for your home.