COMBI, SYSTEM OR OPEN VENTED BOILER?
There are 3 gas boiler types available; Combination, System and Open Vented.
- Combination Gas Boilers - heat for your radiators AND hot water on
demand. See the Dimplex Combi - System Gas Boilers - a sealed system with a water storage cylinder
See the Dimplex System - Open Vented Gas Boilers - a small, quick and easy replacement solution
See the Dimplex OV
You can read all about the 3 models here in the Dimplex Gas Boiler Brochure
Combination Gas Boilers
Combination or Combi's are now the most used form of central heating boilers. They are able to provide both heat for your radiators and hot water through your taps all through one packaged unit.
- Eliminates need for cylinder and water storage - frees up your airing cupboard
- Hot water generated only when needed
- Potable drinking water at all taps
- Fewer components in the central heating system - lower cost and time on installation, plus increased efficiency
- Require least amount of plumbing - free up your airing cupboard
- Most popular installed system
However
- Limited to water from one/two outlets at a time - as combi is supplying all hot water to entire home
- Lower flow rates - as water is heated on demand and hence it may take longer to run a bath
(Some advanced combi boilers incorporate a small hot water cylinder. Installation is still easy with reduced components but the boiler stores some hot water to enable it to meet initial demands for hot water). - Hot water temperature - this can be influenced by the temperature of the incoming cold water and the flow rate. As a result it is essential that the power of a new boiler is matched to your heating needs.
Sealed System Boiler
Many people with older systems such as open vent boilers choose an unvented sealed system for their central heating and hot water.
A system boiler (also known as a closed or sealed system boiler) works on the principle of stored hot water. This means that you will need an airing cupboard or other space for the hot water storage tank. Although a tank is needed in the airing cupboard, a system boiler still needs less space than a traditional open vent or heating only boiler, which utilises a second tank in the loft. Also, many of the individual components of the heating and hot water system are built in, which means that installation is quicker, neater, easier and more efficient.
- Run hot water from a range of outlets simultaneously (minimal drop in pressure and temperature)
- Good water pressure
- Great choice for a larger home or family with hot water needs that can't be met by a combi boiler
- Free up loft space in your home. (You will need a tank in the airing cupboard though).
View the Dimplex System Boiler
However,
- Have to wait for water to be heated when you want it
- It could run out if it's used too quickly
- It is more expensive than simply replacing your boiler with the old system
Open Vented Boiler (Heat Only)
Traditional central heating systems have a hot water storage tank (in an airing cupboard) and a feed and expansion tank (located in the loft if Open Vented). Having a hot water storage ability allows these systems to deliver large amounts of hot water at short notice. The hot water capacity is only limited by the size of the hot water tank and the ability of the boiler to renew the hot water when depleted.
However, the additional components and hot water storage also contribute to reduced energy efficiency, higher installation costs and a more complex system.
Open Vent heat only boilers can reduce heating bills from day one and are a popular choice for homeowners thanks to their high energy efficiency and compact dimensions that allow it to fit within a standard kitchen cupboard. If you currently have an Open vent boiler, then the easiest and most cost effective option is to replace 'like with like'!
- Two tanks in the loft
- Cylinder fed from Storage tank
- Boiler heats cylinder & radiators
- F&E tank maintains correct water level in system
- Showers, taps, baths in any room at same time
- Potable drinking water at kitchen tap
- Traditional UK system
View the Dimplex Open Vented Boiler
