Boulder County voters approved Ballot Issue 1A in 2008 allowing for the issuing of bonds to fund special financing options for renewable energy and energy efficiency improvements in the home, including biomass systems.
Incentive specifics available here:
Residents of the city of Fort Collins may apply for a zero interest air quality loan towards the replacement of an old wood stove upgrade to either a pellet stove/insert or certified wood stove/insert. Loans are available for a minimum of $1,000 to a maximum of 3,000. Qualified applicants need proof of old stove recycling and a building permit.
Program website here
Denver-Metro area, Colorado: Prohibits sale and installation of new or used uncertified wood burning appliances.
Denver Metro area: The installation of fireplaces is not allowed unless they are equipped with an EPA Phase II wood or pellet burning insert, or electric or gas log.
Summit County, Colorado: Forbids the installation of a non-certified wood stove in a new home or as a replacement unit for an existing non-certified stove.