Free Air Requirements

All wood burning and multi-fuel stoves require air for combustion. This is a requirement under Building Regulations Document J.

In older houses it is deemed that there is sufficient air within a room to allow for the combustion of appliances of up to and including 5Kw. This means that appliances up to 5Kw do not require an air vent. 

On later, more air-sealed houses there is less leakage through doors and windows, therefore more air is required for the full output of the appliance.

Older houses that have had modifications to include double-glazed windows or other insulation fractures may also require additional air.

Additional air may also be required if exterior fractures are involved, for example extractor fans in adjacent kitchen areas, or heat recovery systems. This would be ascertained upon appliance commissioning.

Below is a simple calculator to assure that the correct amount of free air is allowed for the installed appliance.

Please note that installed air vents should not have the facility to close.