For maximum performance keep the duct straight and short. Use the shortest route with the fewest turns possible. 45 degree turns are better than 90 degree turns. Be sure to use an external roof or wall cap. If in doubt, consult a qualified installer and ensure the guidelines in the installation manual are followed. Please note each bends reduces the suction up to 60 – 75 m3/hr. Under Indian cooking standards the ducting should not be more than 12 – 14 rft with maximum of 2 bends. You should never exhaust air into spaces within walls, ceilings, attics, or garages. The humidity and grease collect in the space and present a huge fire danger.