draft hood[′draft ‚hu̇d]
A device used to facilitate the escape of combustion products from the combustion chamber of an appliance, to prevent a backdraft in the combustion chamber, and to neutralize the effect of stack action of the chinney or gas vent on the efficient operation of the appliance.
1op of a flue to prevent downdrafts.
2. An open enclosure over a gas-fired furnace. Serves to create a stack effect which more readily mixes the exhaust gases with air and directs the mixture to the chimney; prevents back drafts from getting into the furnace.