Types of boiler explained: Combi, System & Standard boilers

#Getting Started

When it comes to choosing a new boiler for your home, there is lots to consider. As well as what type of boiler e.g. Combi, System and Standard, you need to know which type of the type of fuel you have in your home as this will influence the boilers you can choose from.

Combi boilers

A combination or ‘combi’ boiler heats water directly from your mains water supply, so you won’t need a hot water storage cylinder or a cold water storage tank in the roof space. This provides the added benefit of freeing up space by removing the tanks. By removing these there is absolutely no risk of loft pipework freezing during the cold winter months when you need you heating the most.

If you are looking for a boiler that is both cost-effective as well as energy-efficient then combi’s might be the right choice for you. They are also ideal for anyone needed heated water on demand rather than being heated and then stored in a cylinder.

Due to their compact size and energy efficiency it makes them perfect for cutting bills and fitting in smaller spaces in your home.

Suitable for

Combi’s are suitable for almost any home, but they are best for homes which don’t have multiple people needing lots of hot water all at the same time.

Pros

  • Unlimited heat and hot water on demand.
  • No tank in your loft.
  • They don't take up much space.
  • They are generally cheaper to have installed than other types of boilers because there is no tank and less pipework involved.

Cons

  • The water pressure might be reduced if you need hot water from more than one tap at a time.
  • They do not work well in properties with poor flow rates and/or poor incoming water pressure

Worcester Bosch

Greenstar I

  • Simple boiler controls with clear information on display
  • Wide choice of controls enables greater comfort and economy
  • Low energy pump reduces electrical usage
  • Instantaneous hot water, always available

System Boilers

A system boiler also known as a sealed system has all the same components as a combination boiler without the integral hot water production.

Similar to regular boilers, system boilers work with a hot water cylinder. However, the major heating and hot water system components are built into the boiler itself, making it quicker and easier to install. Also, there is no need for a tank in the loft making it a great option for a home with little loft space.

Suitable for

Larger homes which need to have hot water in more than one place at the same time.

Pros

  • No tanks needed in your loft.
  • Good hot water flow rates
  • Economical to run

Cons

  • The hot water can run out, so you'll have to wait for it to reheat.
  • You need to find room for the cylinder somewhere in your home.

Greenstar system (9Kw to 24Kw)

  • Simple boiler controls with clear information display.
  • Suitable for homes where the heating system includes a hot water storage cylinder.
  • Choice of controls enables greater comfort and economy.
  • Can be used with Greenskies solar panels for energy and cost savings.
  • Low energy pump reduces electrical usage.
  • Large Condensesure style siphon built into the boiler - eliminates frost risk.

Standard Boilers

Standard boilers also known as conventional or regular boilers are ideally suited to larger homes but less are being installed as time passes. These boilers also need a cold water storage tank in the loft to feed the hot water cylinder, as well as a tank that maintains the water level of the central heating system.

These are usually open-vented heating systems which can be sealed if required, i.e. there is a Feed and Expansion tank in the loft.

A standard boiler is a good option when replacing an existing boiler with an older radiator system in place as it might not be able to cope with the higher water pressure that is delivered by system or combi boilers without the pipes being upgraded.

A standard boiler is perfect for homes where a lot of hot water is used at the same time, for example, where there are two or more bathrooms being used at the same time.

Suitable for

Larger homes which need to have hot water in more than one place at the same time.

Pro's

  • Works well with older radiators systems.
  • Best option for homes already with a traditional heating and hot water system.

Cons

The hot water can run out and you'll have to wait for it to reheat.
They take up a lot of space.

Greenstar Ri (12kW to 24kW)

  • Fits in a standard kitchen cupboard.
  • Simple boiler control knob.
  • Suitable for homes where the heating system includes a hot water storage cylinder.
  • Frost protection is also included, reducing frost risk if installed in a garage or loft.
  • Can be used with Greenskies solar panels for energy and cost savings.