Some designs of wood burning stove feature an integral air vent. Such stoves are typically very expensive. You don’t need to use a DR21 air vent with stoves which have integral air vents to prevent a draught in the living room. However, if you do fit a DR21, you will gain the advantage that when the stove is opened (e.g. for lighting or cleaning), dust and ash will not blow into the room. If you are paying over £1000 for a stove, plus the installation fee, you may appreciate a spend of an extra £19.99 on the DR21 air vent to stop the annoyance of extra dust in your living rooms.
What is more, stoves with integral air vents are typically very cold when not lit. This is because they have a direct connection to the outside, through the integral air vent – air from outside will circulate around the stove when it is not in use. So, when unlit, the stove acts in the opposite way to a radiator. It is a giant piece of metal in your living room which will be colder than the rest of the room, and which will cool the room. This means that your central heating bills will be higher, since you must compensate for the effect of the stove cooling down the room when not in use. The coldness of the stove also means it will be more difficult to light, and will take longer to heat up than a stove without an integral air vent.
Installing a DR21 vent onto your stove with integrated air vent overcomes all of these problems.