Wood Energy Basics
There are several different types of wood burning appliances, including stoves, boilers, masonry heaters, and fireplace inserts. There are a variety of EPA-certified wood stoves available with efficiencies up to 83%. Pellet combustion appliances, including stoves, furnaces and boilers, can burn pellets made of wood or other biomass for fuel. Pellet appliances require electricity, whereas wood stoves do not. Outdoor wood boilers are another option, although they are often run inefficiently and emit high quantities of air pollutants. These outdoor boilers can violate Colorado’s air quality smoke regulation and county and municipal regulations may also apply. Hydronic pellet boilers burn wood pellets and can be installed either indoors or outdoors. These units generally have a thermal efficiency of 80% or higher. Wood chip boilers are another alternative available for medium to large greenhouses, schools, or businesses.
Masonry heaters include a firebox, a large masonry mass (such as bricks), and long twisting smoke channels that run through the masonry mass. They can reach very high efficiencies and release little air pollution, but they cannot provide heat quickly from a cold start. Traditional, open fireplaces are more for ambiance and should not be considered a heating appliance. High efficiency fireplace inserts, however, can function almost as efficiently as wood stoves.
Local governments in Colorado can restrict the use of wood burning appliances. Strict restrictions exist in the winter months in the 7-county Denver metro area, although a number of highly efficient wood-burning appliances are exempt from those restrictions. Exemptions can also be requested from local governments if wood is your primary source of heat.
Is Wood Energy Right For You?
Wood energy may be right for you if:
- You want a heating source that is generally more cost-effective than electricity or propane
- You have access to a consistent feedstock – this is especially important if considering a pellet stove
- You are familiar with local building codes and ordinances that may restrict your use of wood heat on certain days
- You are prepared to pay for a professional installation
- You are prepared to regularly operate and maintain your wood-burning appliance
- You have appropriate indoor or outdoor space for storing your wood/pellet feedstock