In 1990, the EPA finalized and passed into law new pollution standards
for Wood and Coal stoves. Many folks are still confused about this issue.
Basically, the new laws apply only to freestanding and built-in "space heaters" which burn wood in a controlled manner (so-called "airtight" stoves). The standards call for these appliances to be able to burn very cleanly, up to 10 times as clean as older stoves. They also must burn cleanly at all settings, from very low to very high. Certain Solid Fuel appliances are exempt from these standards. Coal stoves, open fireplaces, cook stoves and all central heating units are not required to meet these standards.
If you already have a woodstove, don't worry ! All existing stoves and used stoves are "grandfathered" and allowed to be used. The law only applies to the manufacturers. Still, it is smart to upgrade your system to a more efficient model whenever possible. This will help us all clean the air and make better use of our resources.
How Clean is Clean ? The standards measure pollution in "grams per hours" which represents the particles in the smoke released up the chimney. One gram is approx. the amount of smoke released from the entire burn of a cigarette. Older stoves and fireplaces released from 40 to 80 grams per hour of smoke, the new EPA approved stoves produce from 2 to 5 grams per hour.
You can rest assured that the people who make up the Hearth Industry are constantly striving to clean up the air even more. Research in the laboratory has produced experimental stoves which produce less than one gram of smoke per hour....amazing clean !