You'll pay more for systems with higher airflow and lower noise ratings. That's where knowledge of CFMs and sones will come in handy. CFMs refer to the amount of cubic feet of air a vent system can move per minute. The National Kitchen and Bath Association recommends a 150 CFM minimum for all surface cooking appliances. Sones measure noise level. A refrigerator equals about 1 sone; ordinary conversation about 4; and a jet plane landing about 256. The Home Ventilating Institute recommends that kitchen vent fans should not be louder than 9 sones.

Your two basic options are an updraft ventilation hood or a downdraft vent.

Updraft vent hood
Located over a range or cooktop, a vent or range hood works in one of two ways: The polluted air rises, is pulled up by a fan, passes through filters, and is exhausted outdoors through a metal duct. Or a fan draws the polluted air through filters and then recirculates the cleaned air back into the kitchen.

Pros

• Can be used as a decorative element.
• Location over the range or cooktop is the most effective for removing air.

Cons

• Can be hard to keep clean.
• Recirculating hoods may clog up unless you change the filters regularly.
• The fans can be noisy.

Price: From $100 on up into the thousands.

Downdraft vent
Instead of being placed over the cooking area, a downdraft blower is built into a base cabinet. It exhausts air by pulling it down through vents placed on the sides and back of the cooktop. Or you can buy a separate blower with a vent that raises up behind the cooktop while you're cooking and then lowers out of view when you're done.

Pros

• Great for cleaning air around island cooktops where a hood wouldn't work.
• More subtle than an overhanging hood.

Cons

• Doesn't exhaust the steam from taller pots and pans very well.
• Won't catch anything that's not right by the vent.

Price: About $500.