Room sealed stoves with external air supply

External air supply explained

Stoves with external air supply draw the air they need for combustion from outside of the house. This reduces cold draughts in the house, and is ideal, indeed necessary, in modern well sealed houses. This is also known as 'room sealed' because in effect your room is still sealed because the air is not being drawn through the room, but through the ducting.

Stoves that do not have an external air supply draw the air they need for combustion from the room itself. Often dedicated ventilation needs to be fitted to supply this air, and that is a source of cold air coming in to the house. In a modern house with a mechanical heat recovery ventilation system you simply cannot have permanently open ventilation for your stove.

Some stoves which have an external air supply draw all of their air (primary, secondary, tertiary) from the external air supply duct. Some stoves only draw the primary air through the duct, but still draw the secondary/tertiary air from the room. With inset stoves that are installed into a chamber it is often possible to run ducting directly to the chamber and so make the installation room sealed.