Rising energy prices have pushed many homeowners to purchase wood-burning stoves, many of them using tax credits for efficient stoves that expire next month, USA Today reported Friday.
The trend has prompted federal officials to consider updating the 23-year-old certification criteria for stoves, the newspaper reported.
The Environmental Protection Agency said it plans to propose the new rules next year.
"We are not in the business of telling people how to heat their homes," EPA spokeswoman Alison Davis said, but she urged people to purchase EPA-certified stoves and install and use them properly to keep smoke out of the house.
"The technology has improved for wood stoves," Davis said, noting stoves meeting the EPA's 2007 voluntary standards are 90 percent cleaner than older ones.
Of the estimated 10 million wood stoves used in the United States, as many as 80 percent are not EPA-certified and emit 70 percent more pollution than those that are, said Lisa Rector of the non-profit Northeast States for Coordinated Air Use Management.