Wood smoke: Burning for heat

Federal regulations regulate the manufacture, distribution, advertising, sale and installation of newly-installed wood heating appliances. Starting May 15, 2015, new wood burning room heaters (wood stoves, fireplace inserts, pellet stoves) and central heating appliances (furnaces and hydronic heaters or “boilers”) sold must be EPA-certified.

Local governments in Minnesota can and have adopted local ordinances to further regulate wood smoke in their communities, often to address the smoke complaints related to hydronic heaters.

Minnesota rules for wood-fired heating appliances

The Minnesota indirect heating rules may be applied to hydronic heaters. Minn. R.  7011.0520 requires a stack of sufficient height to protect air quality standards. If the wood burning appliance is large enough, the business using the appliance may require obtaining an air emissions permit. Contact the Small Business Assistance program to determine permit requirements for non-household wood burning. 

There are good reasons for not burning garbage in a wood burning appliance. Besides being toxic, the combustion by-products in the resulting smoke wears wood heaters out faster than wood alone. Furthermore, it’s illegal to burn waste materials or garbage in larger residential wood heaters, like outdoor wood boilers and furnaces. Minn. R. 7011.1220 bans small incinerators, which these would become. 

How local governments regulate wood smoke

While federal and state standards help ensure cleaner wood heating appliances are available to homeowner and businesses, sometimes rules about their use and location must be used to address questions about neighborhood exposure to wood smoke. 

Over 60 local governments in Minnesota have passed ordinances designed to address concerns about wood smoke in their communities. Some communities ban hydronic heaters (also called outdoor wood boilers or solid fuel-fired devices (SFHDs)), confer nonconformity zoning code status on currently installed outdoor wood boilers, and/or prohibit new installations. 

MPCA compiled a summary of cities with ordinances addressing the use and location of wood heaters: PDF icon Minnesota local ordinances related to outdoor residential wood-burning boilers 

Model Ordinances

The MPCA collaborated with local government representatives to develop model ordinances to address the problem of particulate matter in the wood smoke produced by outdoor wood boilers. The model zoning and nuisance ordinances help protect neighboring properties from the adverse effects of wood smoke posed by outdoor wood boilers (also called hydronic heaters, outdoor wood furnaces, water furnaces or solid fuel-fired devices (SFHDs)). These model ordinances educate citizens and communities affected by wood smoke and assist property owners in maintaining compliance. These model ordinances were designed so local governments could customize the ordinances to meet their community’s needs.  

    The federal 2015 Wood Heater Rule 

    To protect air quality, the U.S. Environmental Protection Agency (EPA) requires all newly manufactured wood-fired heaters to meet particulate matter emission limits and related performance standards. Model lines must be EPA-certified before they are advertised, offered for sale, distributed, sold or installed in the United States.

    This rule applies to heaters designed to burn coal, corn, or other non-wood fuels if the device can also be used to burn wood.

    This rule does not apply to existing wood-burning heaters already in use before the standards went into effect. But, as the existing fleet of poorly designed older wood heaters in use today is gradually replaced with the new EPA-certified wood-burning heaters, wood smoke air pollution in neighborhoods that heat with wood should go down.

    The 2015 Wood Heater Rule includes the (1) Standards of Performance for New Residential Wood Heaters and (2) Standards of Performance for New Residential Hydronic Heaters and Forced-Air Furnaces 

    The 2015 Wood Heater Rule particulate emission limits become more stringent in two phases (Step 1 and Step 2) to give manufacturers the ability to bring products to market while designing appliances to meet the more stringent 2020 limits. As of May 16, 2017 all new wood heaters must be EPA-certified to their Step 1 emission limits to be legally manufactured, advertised, distributed, offered for sale, sold or installed. All new wood heaters must be EPA-certified to the Step 2 emission limits by May 16, 2020.

    “EPA-certified" for a wood heater appliance, such as a wood stove, means that before a newly manufactured model line of the appliance can be sold into the U.S. market, the manufacturers must demonstrate to EPA that the model line meets emission limits.  Once the manufacturer makes that demonstration, the model line can be sold in the U.S and must have a permanent label describing it is EPA-certified to the performance standards in effect at the time it was certified.   

    What types of wood heaters does the 2015 Wood Heater Rule cover?

    Central heaters: Fuel-burning devices designed to burn wood or wood pellet fuel that warms spaces other than the space where the device is located, by the distribution of air heated by the furnace through ducts or liquid heated in the device and distributed typically through pipes. These devices include residential forced-air furnaces (small and large) and residential hydronic heaters. 

    • Residential forced-air furnaces: Fuel-burning devices designed to burn wood or wood pellet fuel that warms spaces other than the space where the furnace is located, by the distribution of air heated by the furnace through ducts. 
    • Hydronic heaters: Sometimes called outdoor wood boilers, outdoor wood furnaces or water stoves. They use a liquid like water to transport the heat through a closed system of pipes for space or water heating.  They may be located inside or outside of the home. 
    • Residential hydronic heaters: Fuel-burning devices designed to burn wood or wood pellet fuel for the purpose of heating building space and/or water through the distribution, typically through pipes, of a fluid heated in the device, typically water or a water and antifreeze mixture. 

    Residential wood heaters: means an enclosed, wood burning-appliance capable of and intended for residential space heating or space heating and domestic water heating. These devices include adjustable burn rate wood heaters, single burn rate wood heaters and pellet stoves. Wood heaters include:

    1. Free-standing wood heaters—Wood heaters that are installed on legs, on a pedestal or suspended from the ceiling. 
    2. Fireplace insert wood heaters—Wood heaters intended to be installed in masonry fireplace cavities or in other enclosures.
    3. Built-in wood heaters—Wood heaters that are intended to be recessed into the wall. 

    List of Certified Wood Heating Appliances

    EPA maintains the current lists of EPA-certified wood-fired room heater models such as woodstoves, fireplace inserts and heating fireplaces, for central heaters such as hydronic heaters, and for central heaters such as forced-air furnacesSee EPA’s residential wood heaters page for more information.  

    Complying with the 2015 Wood Heater Rule

    The 2015 Wood Heater Rule established regulations that apply to wood heater manufacturers, vendors, distributors and installers. Check out the following guides and EPA’s residential wood heaters page for more information: