Regulations:
Washington was the first and for a long time, the only state, that forbid the sale and installation of older, non-certified stoves. It was also the first and only state to maintain stricter state-wide emissions regulations by requiring non-cat stoves sold and installed in Washington be no more than 4.5 grams an hour as of 1992, and catalytic stoves no more than 2.5 grams and hour. Washington was the only state to effectively ban outdoor wood boilers. It also required masonry heaters and fireplaces to emit no more than 7.3 grams per kilogram.

Tacoma-Pierce County, Washington: As of October 2015, it is illegal to purchase or operate an uncertified wood stove in the Tacoma-Pierce County Smoke Reduction Zone.

Numerous local and regional air agencies in Washington state offer periodic or ongoing change out incentives. Check with your local air agency.