We do a number of different type of cowls. They can be broken down into three categories.
Cowl that protect your chimney – Rain Cowls, Chimney Caps, Chimney Capping Cowls and Bird Guards
Cowls that prevent or help alleviate down draughts (anti down draught cowls) - Spinner Cowl, Junior Cowl, All Purpose Anti-down Draught Chimney Cowl.
Cowls to reduce wind noise and down draught- Dragon Cowl.
Cowls to stabilize draught in a chimney - Flue Cube
Cowl to mechanically vent fumes
Other factors that effect up draught/downdraught.
All flues should be checked for blockages caused by falling soot, birds’ nests or masonry debris, faults that will usually be revealed by sweeping. This should be done regularly, particularly when wood or solid fuel has been burned. Any holes in the chimney structure should be repaired, as air leakages into a flue will cool the gases, reducing the up draught, and can also cause the emission of toxic fumes. An efficient hearth must have a good air supply. A common cause of air starvation is excessive draught proofing (particularly when UPVC replacement windows have been fitted), and additional ventilation may therefore have to be fitted adjacent to the fire, door or a window left open.