ARLINGTON, Va. — A study commissioned by the Vent-Free Gas Products Alliance product section of the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) on nitrogen dioxide (NO2) emissions from vent-free gas fireplaces, logs, inserts, space heaters, and stoves found that the use of those appliances in tight homes does not result in NO2 concentrations that exceed IAQ guidelines.
Tight homes are those that are designed to be as airtight as possible, usually with mechanically controlled ventilation. Today, many new homes are designed in this manner. The study included 100,000 simulations.