DR21 Air Vent Cover


Fed up with having cold air blowing through wall vents? The DR21 air vent cover is the answer! It’s very simple; there are no moving parts, it just makes the air zigzag before it enters the room so it slows it down and doesn’t blow through on windy days. It fits easily onto existing 4 inch diameter ventilation holes, simply remove the existing vent cover and fit the DR21 in its place.


Inventor David Gattie had installed over 1100 woodburning stoves. Having installed a product that made the home more cosy and energy efficient, he then had to drill a hole in the wall for ventilation. He realised that people hated the draught caused by the air vent, and decided to do something about it. Thus the  DR21 anti-draft Air Vent was devised.

Many customers would simply block the vent. This is extremely dangerous as it is there to provide air for combustion so as to avoid carbon monoxide from being emitted. It will make the stove inefficient, giving out less heat for the same amount of fuel.

An inefficient stove will not burn cleanly, resulting in higher emissions and increased pollution. It also means that the flue needs sweeping more often and the glass may well go black.

The DR21 has patent pending, has been independently tested by the Building Research Establishment, been approved by HETAS (the governing body for all solid fuel installations) and produced to ISO 9001:2015 standards entirely in the UK.

Any fire needs Fuel, Heat and Air to burn efficiently. The government is currently tightening up the legislation covering solid fuel installations; the most important change is to ensure that everyone burns good quality fuel, and the creation of Woodsure, a certification scheme to ensure that wood being sold is satisfactory, is already in existence; a proper supply of air is the second most important thing, and the DR21 vent means that this does not have to be accompanied by a draught.

Having been designed by someone who has had to install literally hundreds of vents, you can be assured that the DR21 vent is very quick and easy to fit! quote customer from Cardiff “you said it would take 15 minutes to fit, it took me 7 and the result was immediate!”

The DR21 air vent is a new design which allows air necessary for combustion to be drawn into the room, but stops air being blown in.

  • HETAS approved
  • Throughput equivalent to 3400mm² of free air
  • Uses a 4 inch hole
  • Protrudes 3 inches from the outside wall
  • Enables you to burn less fuel
  • Creates a warmer room

How does the DR21 vent cover work?

A standard louvered vent lets air blow straight through the wall. The DR21 disrupts the airflow so that it can’t just blow straight in. However as soon as you light your fire and need more air for it to burn efficiently, the air will travel through the DR21 more quickly. Have a look at this demonstration video to see how it works.

cross section diagram of a DR21 air vent

How do you fit the DR21 air vent cover?

If there’s already a hole drilled through with a louvred vent fitted, it’s really easy. Simply remove the louvered vent, drill holes for the back plate of the DR21, fix the back plate to the wall, pop in some adhesive and fix in the top plate. Have a look at this video for a demonstration.
If you’re just about to have a wood burning stove fitted then it’s likely the installer will need to drill a hole in the wall behind the stove in order to create sufficient ventilation. In that case show him or her your DR21 that you’ve just purchased and ask them to fit that instead of the standard louvred grille they were just about to put in place for you.
You can see the full instructions that come with the DR21 air vent cover here: DR21 Fitting Instructions