The Chimney Sweep Online Fireplace, Woodstove, Gas Stove and Barbecue Shop
This question comes up quite often, even though it is rapidly becoming a moot point, as more and more states now require vented exhaust hoods for all new gas range installations. Nonetheless, there are still lots of old, unvented gas range installations out there, so here are the facts:
It turns out there is a huge difference in daily exhaust exposure between unvented gas cooking appliances and vent-free gas heaters.
According to a study by the State of Illinois, a typical household gas range produces the exhaust from an average of 6.4 cubic feet (6,528 btus) of gas per day (this average is computed on an annual usage rate, and includes the peak usage season during the Holidays).
Vent-free manufacturers typically recommend limiting use to a maximum of three hours per day, so a 25,000 btu vent-free operated according to the
manufacturers guidelines introduces the exhaust from 75,000 btus of gas into the breathing space every day during the 6-month heating season,
for an annual average of 37,500 btus per day (nearly
6 times the average daily emissions created by an unvented gas range).