Minster Stoves & Heating
Guide to the Different Types of Gas Boiler
Guide to The Different Types of Gas Boiler
Different Types of Gas Boiler

It’s important to understand the difference between the different types of gas-fired boiler available when thinking about replacing or upgrading your gas boiler – here’s our guide to the different types of gas boiler.

What is “Boiler Plus”?

The Department for Business, Energy and Industrial Strategy (BEIS) introduced Boiler Plus in 2018, which has an impact on boiler manufacturers, installers, and homeowners.

”Boiler Plus” has been introduced to increase the efficiency of homes across the UK by stating that all gas boilers have to meet certain requirements.

The most notable change applies to the minimum performance standard for domestic gas boilers in England, with the efficiency level of all boilers manufactured and installed needing to be at least 92% ErP. As well as the minimum level of efficiency, some other measures have to be taken into account too:

  • Installers must install time and temperature controls for all gas and oil boiler installations.
  • Installers must also include one of the following in combi boiler installations: Weather compensation, Load compensation, Flue Gas Heat Recovery, or Smart controls.
  • Installing a Combi boiler that doesn’t meet the “Boiler Plus” legislation could lead to a hefty fine for you, whether you’re an installer or a homeowner.
Types of Gas Boilers
There are three main types of gas-fired boiler to choose from:
  • Combi Gas Boilers – Combi (or combination) boilers are the UK’s most popular type of boilers for gas central heating and domestic hot water.

    As with other types of boilers, they provide heat to your radiators. However, a ‘combi’ only heats hot water for your taps on demand, for example when a hot tap is turned on or you run a hot shower.

    Therefore, it does not waste energy by keeping a tank full of water heated when it’s not needed.

    Other pros of combi boilers are that they do not require extra space for a water tank, and they deliver water to your taps at mains pressure – which makes for a more powerful shower.
  • Conventional Gas Boilers – Many older houses often have conventional boilers.

    The heating system consists of a cold water tank (usually in the loft), a separate expansion cistern, and a pump.

    Installing a new conventional boiler in your home is a pretty straightforward job. Most existing systems can accommodate the installation of conventional boilers, making them a very versatile option. They’re also easy to use.
  • System Gas Boilers – System boilers particularly suit heating larger houses that use more hot water – (i.e. houses that have more than one bathroom).

    A system boiler pumps hot water to the radiators and to the hot water storage tank or cylinder (usually in the airing cupboard or loft).

    With a system boiler, you can run more than one tap at the same time, so there won’t be a problem if you want to do the washing up while someone else is having a shower.
Combi Boiler
  • Combi boilers are the UK’s most popular type of boiler
  • Hot water for your taps & central heating system is supplied directly from the boiler
  • Ideal for smaller homes & homes with one bathroom
  • Can be an economical option, as combi boilers only heat the water you use
  • Provides unlimited hot water on demand
  • A great space-saving solution with no need for a separate cold water tank or hot water cylinder
  • Depending on your mains water pressure, the flow of hot water could be reduced if you’re using more than one tap at the same time
  • Water can sometimes take a few seconds to heat up
Conventional Boiler
  • They send heated water to your radiators and a hot water cylinder
  • Better suited to larger homes, especially those with more than one bathroom
  • Can provide hot water to more than one tap at the same time
  • An electrical immersion heater can be fitted to the hot water cylinder as a backup, should your boiler breakdown
  • Hot water is limited to the capacity of the cylinder, so if it runs out you’ll need to wait until it heats up again
  • Space is required for a hot water cylinder and a cold water tank which is usually located in the loft
  • You’ll need programmable controls to heat the water in the cylinder, so it’s ready for when you need it
System Boiler
  • System boilers work in a similar way to conventional boilers but have some external parts already built-in
  • There’s no need for a separate feed and expansion tank (usually located in the loft)
  • Ideal for larger homes and homeowners who want extra storage space in their loft
  • Hot water can be supplied to more than one tap at the same time
  • An electrical immersion heater can be fitted to the hot water cylinder as a backup, should your boiler breakdown
  • Hot water is limited to the capacity of the cylinder, so if it runs out you’ll need to wait until it heats up again
  • To ensure hot water is available for when you need it, you’ll require programmable controls to heat your water in advance
Scroll to Top