An Industry Viewpoint: Unvented vs. Vented
Canada should not change its regulations preventing unvented gas appliances. From Mechanical Buyer and Specifier.

Vent-Free Gas Heaters - How Safe?
A look at how unvented heaters affect indoor moisture and air quality. From the Journal of Light Construction Online.

Vent Free Appliances: A Scientist Speaks Out
From The Chimney Sweep.

Vent-Free Gas Appliances
Things to know before you choose one for your home, from Duke Chimney Services.

Trade Organizations

Consumer Guide to Vent-Free Gas Products
Product description, codes & standards, from the Gas Appliance Manufacturers Association.

Vent-Free Gas Products Alliance
Exists to assure that current markets are preserved and that barriers are removed in all trade areas for future growth of the industry.