translate English to French: Piping for flue gas discharge and fresh air intake comprises either a double concentric pipe of about 12 cm in diameter (for the most common residential boilers) or two separate pipes (one for fresh air, the other for combustion gases). The external connection is either on an exterior wall or through the roof.
Elles offrent un confort de chauffage supérieur et réduisent la consommation d'énergie.