Heating with Wood
There is no form of home heating more enjoyable than a fire. Many people supplement their conventional heating systems with wood heat (or pellet), and others use wood as their major source of heat. With other fuels scarce and expensive, many people are turning to wood for home heating.
Do you live where temperatures can drop into the negatives and stay there, or, where winters are mild, and cold days alternate with warm? An occasional fireplace fire may be sufficient, but if you want to really reduce your heating costs, you probably need something more.
What system is best for you?
Decide how much space you need to heat, and for how long. Also, think about outdoor storage space for firewood and indoor space near the stove (or stoves) for a day's supply of wood and kindling.
To understand fuel efficiency, you need to know how wood burns.
Wood burns in three stages. First, heat provided by burning small pieces of dry kindling produces temperatures high enough to ignite the outside of larger pieces of wood. In this stage, heat is needed to drive off the moisture present even in the driest wood. The heat used in this process is lost so you can see that dry wood is important. In the second stage, temperatures approach 500 degrees F and a chemical breakdown of the wood begins. Volatile liquids and gases are driven off, leaving charcoal behind. About half the available heat is in these gases, however a temperature of at least 1,100 degrees F is needed to ignite them and more air is needed to support combustion. Charcoal burns in the third and final stage at temperatures above 1,000 degrees. Since fresh wood is usually added during the burn, these stages are not separate - all three may go on simultaneously.
Wood is a 100% all natural, renewable resource.
Heating your home with a high efficiency, EPA (Environmental Protection Agency) approved fireplace, stove or insert releases no more carbon dioxide than a dying tree would lying on the forest floor. In fact, when the entire carbon cycle is considered, an EPA approved fireplace heats your home more efficiently and with less impact on the environment than any other heating fuel option.
Increase Fireplace Efficiency
Glass doors provide a convenient and attractive method to seal the fireplace opening and reduce heat loss up the chimney. They come in a variety of sizes, shapes, styles, and finishes to match any decor.
Fireplace grate heaters may improve efficiency. The tubular grate acts as a heat transfer unit, moving air through the tubes by convection or with a blower. Many are designed to work with glass doors.
These fireplaces are so well insulated they can be installed safely in a stud wall. They are cheaper to install, and with a brick or stone face resemble a more expensive masonry fireplace. Forced air vents may help them serve more than one room, or they may be connected to a central heating system. With glass doors and an outside source of combustion air, these units are quite efficient. Prefabricated fireplaces are double-walled steel units designed to be encased in the masonry of the chimney. They are not nearly as efficient as a zero-clearance fireplace. Intakes near the base draw cold air in from the room, circulate it through the fireplace walls, and exhaust it, warmed, back into the room through vents above the fireplace.
You have to be building or remodeling to install a prefabricated or zero-clearance fireplace. However, if you already have a standard fireplace you can install a Fireplace Insert. These fit partially or completely in a fireplace. Unlike a freestanding stove, these take up little or no floor space. Some require forced air blowers and others transfer heat by radiation. All seal air-tight and achieve 50 to 60 percent efficiency.
Freestanding Wood Stoves
Freestanding wood stoves come in many models, sizes and shapes. Stoves are divided into two classes - airtight and non-airtight. The pot-bellied stove and the parlor stove, popular earlier in the century, and the Franklin stove popular today are non-airtight. These are less efficient because entering air is not completely controlled. Air control is important since the rate of combustion and thus the rate wood is used depend on it. Without proper air control, gases from the wood escape up the chimney unburned. Most modern stoves are made of cast iron, sheet steel, or a combination. Cast iron resists wood acids and oxidation or burnout. Thin sheet steel, in combination with cast iron, has been used in stove building for a number of years. It was usually lined with firebrick or with cast iron to reduce oxidation. Thicker plates of sheet steel are used in modern airtight stoves. Joints are welded to prevent air leakage. A smart buyer will look for guaranteed performance. The heavier plates will eventually burn out. Lining with fire brick or cast iron will eliminate burnout, but make the stoves heavier and more expensive.
Wood is a widely used heating fuel: approximately a third of all homes use wood at least occasionally to provide space heat. Wood can be an effective and economical source of heat, provided all necessary steps are taken to ensure efficiency, environmental health, and fire safety.
 University of Florida, Institute of Food and Agricultural Sciences (UF/IFAS)