hello, actually, the price should be determined according to the actual needs of your family! Prices are expensive and inexpensive, depending on which brand you choose. Also, excuse me, does your family cook or run a restaurant? For your own household use, do a good job of ventilation, generally use a range hood, and if you are in a restaurant, you'd better install a fume purifier! Hee hee, that's what we do. You can ask us to see how much air volume we need!