Follow line A on the graph if your home is/has:
- Well insulated;
- Floor and wall insulation.
Follow line B on the graph if your house is/has:
- Reasonably insulated;
- Minimal double glazing;
- Minimal floor and wall insulation.
Follow line C on the graph if your house is/has:
- Poorly insulated;
- No double glazing;
- No floor and wall insulation.
Are you unsure about the insulation in your home? Then ask for personal advice when you purchase a fire or stove.
Open and closed combustion
Combustion, whether it is gas or wood, always requires oxygen. Combustion can take place in an open or closed combustion system.
Open combustion system
You may initially associate the word “open” with a traditional open fire. An open fire is certainly an example of an open combustion system that is less efficient, with the required oxygen being extracted from the room in which it is installed. A wood-burning fire or stove with a glass door usually also draws the oxygen from the room, but because a higher temperature is achieved, it yields much more efficiency. There are also gas fires with open combustion. However, they have special requirements with regard to safety and ventilation in your home.
Closed combustion system
With a closed combustion system, the oxygen is supplied from outside and the flue gases are removed by the same concentric flue. The appliance is therefore completely sealed from the room in which it is installed with no depletion of air from within the room. Combustion takes place very efficiently under these ideal conditions.
Open and closed combustion for wood-burning fires and stoves
In principle, wood-burning fires and stoves always have an open combustion system. It is important to know that if you choose a wood-burning fire or stove, your home needs to be well ventilated.
In exceptional circumstances, such as homes that have a 'balanced ventilation system', there are fires and stoves with an external air connection. An increasing number of fires and stoves are fitted with this facility or offer it as an option. With this system, the combustion air is extracted from outside the building.
Do you have a home with no chimney? Bear in mind that, with a wood-burning fire or stove, the flue must always go upwards and out through the roof and must end above roof ridge height.
Open and closed combustion for gas fires and stoves
In principle, the recommendation for gas fires and stoves is to always choose a closed combustion system. As the system extracts oxygen from outside, therefore not from the room where the fire is installed, this type of system is ideal for modern, well-insulated and mechanically ventilated homes.
Another advantage of a closed combustion system is that in many cases the flue can easily be fed through the outside wall or the roof. This means that you can be more flexible in your choice about the exact location in which your fire or stove will be installed. Do you want to connect the gas fire or stove to an existing chimney flue? Then an open combustion system may be an option, because it requires a smaller flue. Read more information on ventilation outlets for your fire or stove here.