Brunner designed the air supply to the combustion chamber in such a way that the air entering the furnace passes in front of the glass from above and below and creates protection against soot and dust settling on the glass. By design, the air is supplied very close to the glass and provides 100% protection against contamination.

Chimney: the draft of the chimney depends on the diameter, height and shape. When choosing a furnace, you need to calculate the draft of your chimney and select the appropriate model. If the draft in the chimney does not meet the parameters of the firebox, the glass will get dirty during operation. In the case of negative pressure, the supply of air for combustion will be insufficient and the intensity of blowing the glass will not allow to provide full protection against pollution. Air intended for blowing the glass will immediately burn and not protect the glass. The thrust in the chimney can be increased with the help of a deflector (unfortunately, it adds thrust only in the wind).

Wood moisture, quantity and use: the quality and quantity of fuel also has a large effect on the cleanliness of the glass. The main condition is the use of dry wood with a moisture content of no more than 20% (12 months of natural drying). In case of low temperature in the combustion chamber, the gases condense on the cold glass together with the soot. The optimal combustion temperature can be maintained with the help of the automatic air supply system EAS/EOS. This system guarantees optimal operation of the fireplace and will help avoid many mistakes, as well as save fuel consumption.