4. Temperature Gradient – and Open Fires

Open fires can be a particular problem because of the large volumes of cold air they have to drag into the room simply to keep going. Since this is drawn in at floor level, it is always cooler than the surrounding air. Furthermore, it's not just static as in earlier examples but is actually flowing across at ankle level in a continuous stream (A.)

Ducting a supply of fresh air to the fire through an under-floor channel can drastically reduce the problem of temperature gradient and ankle draughts (B.)

Note that the situation described in this frame applies only to open fires and to stoves that are being run with the doors open for prolonged periods. When a stove is run with the doors closed, the amount of air consumed is negligable and highly unlikely to generate any noticable draught.

Building Regulations now require a minimum volume of fresh air to be supplied to any room containing a heating appliance that burns fuel. It generally makes sense to duct the air as close to the appliance as possible.