Have you ever seen a fryer for restaurant fitted with a lid and a filter ? No. To avoid bad smell professionals are simply using an exhaust. Indeed any lid with a filter will create condensation with immediate fall down of steam into the oil : food will be fried but not crusty and the oil will deteriorate quicker. Professionals are using deep fat frying technology : a heating element and 2 stainless steel thermostats directly situated into the oil for an immediate reaction : quick temperature rising, very precise temperature regulation for a perfect cooking result as well as safety control.