Types of Wood-Burning Appliances
People use several types of wood-burning appliances to heat their homes, either as a primary source of heat, as supplemental heat, or for ambiance.
There are two major types of wood-burning fireplaces, traditional masonry fireplaces that are typically built of brick or stone and are constructed on site by a mason; and “low mass” fireplaces that are engineered and pre-fabricated in a manufacturing facility prior to installation. Most fireplaces, whether masonry or low mass, are not used as a primary source of heat; their function is primarily for ambiance. Fireplaces are typically very inefficient heaters. Find EPA-qualified models.
Fireplace inserts are similar in function and performance to free-standing wood stoves, but are designed to be installed within the firebox of an existing masonry or metal fireplace. A certified installer will make sure the flue liner in your masonry chimney is installed correctly. If your fireplace is factory built (or "zero-clearance"), you must use an insert that was specifically designed and tested for your unit to make it more efficient and less polluting. Find EPA-certified models.
A fireplace retrofit is a device that is installed into an existing wood-burning fireplace. The existing fireplace can either be factory built or masonry construction. The primary purpose of the retrofit is to reduce wood smoke pollution from existing fireplaces. A fireplace can be retrofitted with a more efficient gas stove or an EPA-qualified retrofit device. If installed and operated properly, fireplace retrofit devices can reduce pollution by approximately 70%.
A wood stove is an appliance that is usually made of cast iron, steel, or stone. Wood stoves that burn wood for fuel can be used as a primary or secondary source of heat. Most stoves in homes are not EPA-certified. EPA-certified stoves are cleaner burning and more energy efficient.
Gas stoves are designed to burn either natural gas or propane, and are typically very energy efficient. The fire in today’s gas stoves looks much like a real wood fire. They emit very little pollution, require little maintenance, and can be installed almost anywhere in the home. Gas stoves can be vented through an existing chimney, or directly vented through the wall behind the stove. While some gas stoves do not require outside venting, EPA does not support use of these models due to indoor air quality concerns.
Hydronic heaters (also called outdoor wood heaters or outdoor wood boilers) are typically located outside the buildings they heat in small sheds with short smokestacks. Typically, they burn wood to heat liquid (water or water-antifreeze) that is piped to provide heat and hot water to occupied buildings such as homes, barns and greenhouses. However, hydronic heaters may also be located indoors and they may use other biomass as fuel (such as corn or wood pellets). Find EPA-certified hydronic heaters.
NOTE: EPA’s hydronic heater voluntary program no longer exists. Hydronic heaters are now regulated under the 2015 Wood Heater NSPS. Most of the EPA-qualified models for this program have been automatically deemed EPA-certified under the 2015 NSPS if they were tested were EPA Method 28 WHH and meet the 2015 Step emission limit. Frequent questions about the hydronic heater program.
Forced-air furnaces (also known as warm-air furnaces) are designed to burn cordwood, wood pellets or wood chips to heat an entire residence. Heat from these furnaces, which are typically located indoors, is distributed through ducts using a blower fan. Stacks or chimneys for these furnaces are generally on the roof of the home they heat. Large forced-air furnaces are capable of outputting 65,000 BTU per hour or more while small forced-air furnaces output less than 65,000 BTU per hour. Find EPA-certified forced-air furnaces.
A masonry heater is a site-built or site-assembled solid-fueled heating device, consisting of a firebox, a large masonry mass, and a maze of heat exchange channels. It stores heat from rapidly-burning fires within its masonry structure, and slowly releases the heat into the home throughout the day. Masonry heaters are typically very efficient heaters, and currently do not require EPA certification. The Masonry Heater Association of North America Exitprovides more information on masonry heaters and installers in your area.
Pellet stoves are similar in appearance to wood stoves; however, instead of wood, pellet stoves burn a renewable fuel made of ground, dried wood and other biomass wastes compressed into pellets. Pellet stoves operate by pouring pellets into a hopper which feeds automatically into the stove. Unlike wood stoves and fireplaces, most pellet stoves need electricity to operate.
Decorative Fireplace Gas Logs
Decorative fireplace logs can be installed in an existing fireplace. While not designed to be a significant source of heat, decorative logs provide an alternative to burning wood. Because they burn either natural gas or propane, they have low emissions.