Burning Wood for Heat

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Burning Wood for Heat

By Marilyn Pribus

There was a time when people heated with separate fireplaces or stoves in most rooms, burning wood or coal. People still appreciate such heating devices and see fireplaces with their cheery flames as very desirable.  In fact, having a fireplace gives properties an edge when they are on the market.

Still, while the glow of a fire is romantic and welcoming, fireplaces are a very inefficient way to heat a home.  Much of the heat goes straight up the chimney, and leaving the damper open as the fire dies is basically like having a window wide open.

In fact, a simple fireplace is the least practical way to heat a home with a heat efficiency rating of only about 10 percent.

Greater Efficiency
Fireplace inserts and free-standing wood stoves are both considerably more efficient than a simple fireplace, typically serving up three times the heat with one-third as much wood.  Freestanding wood stoves usually provide the most heat, but they need clearance from walls for safety and must stand on a fireproof base.

EPA-certified inserts and stoves keep more heat inside because the chimney is closed except for necessary venting. They also burn cleaner than traditional fireplaces because modern inserts and stoves burn more efficiently, often recirculating heated air within the unit so there is less air pollution released to the outside. Still, most are not really airtight and they can get sooty and need cleaning.

Traditional stone or brick fireplaces are usually lined with special fire-resistant bricks, so special inserts may safely be installed. Inserts are a good way to retrofit for better heat retention and are also safer than an open hearth for children or pets. Airtight glass doors prevent much heat loss and let you see the flames. There are also systems—either original equipment or add-on options—which use fans to direct more of the heat into the room.

Increasingly these days, many people choose a high-efficiency wood-burning fireplace.  This is basically a factory-built woodstove lined with refractory bricks that withstand high temperatures yet have low thermal conductivity to keep the heat inside the fire box.

These stoves can be safely installed right into the wall of a new house or during a retrofit. They don’t need special clearance or even a hearth, although they do require a chimney. These systems can make a significant dent in home heating bills, especially for people with access to free firewood.

What To Burn
Most people burn wood which is plentiful in our region.  Downed and dead wood may be collected for personal use in the George Washington and Jefferson National Forests with a $20 annual permit. Fireplaces can also be retrofitted with “logs” that burn natural gas or propane. Although pellets are more expensive than firewood, pellet stoves are convenient because they burn very cleanly and can be vented through a wall rather than requiring a chimney.

Wood burning is actually carbon neutral since a wood fire releases no more carbon than a tree does decaying naturally in the forest—although it does it a lot faster. In addition, the EPA-certified wood stoves available today produce limited harmful emissions thanks to their closed-combustion burn systems.

Whether in a stove or a fireplace, however, it’s important to burn only dry, well-seasoned wood as you’ll see in the next section.

Fireplace Safety
Always have professionals install any fire-burning system. They are familiar with the guidelines and fire regulations issued by the National Fire Protection Agency, the Underwriters Laboratory, and local building codes.

In our area, about half of all heating fires are in chimneys, stovepipes, and heating devices. It’s crucial to have an approved, properly-sized stove or insert and a safe liner for your chimney.  It’s also important to have working smoke alarms in the home. Going back to Standard Time from Daylight Savings Time is a good reminder to check the batteries in your smoke alarms.

In fact, it’s better to install fresh batteries, even if the old ones still have some power. Use the old batteries in items that aren’t critical to your family’s safety.

An annual chimney inspection is also essential to check for cracks, debris, or creosote. Creosote is a time bomb. It can be any combination of black or brown, flaky, sticky, crusty, or glossy. It is created primarily by burning unseasoned wood which uses a lot of energy to vaporize the sap instead of producing heat. A restricted air supply such as a partially closed damper or an overloaded fuel box also results in a cooler fire with cooler smoke staying in the chimney longer leading to creosote formation.

Highly combustible creosote build-up can cause chimney fires. These fires often burn so hot they can disintegrate mortar, liners or tiles, providing space for flames to ignite the house itself. Conversely, they can also be slow burning in places with meager oxygen supplies, setting off smoke alarms but being difficult to locate.

Use a fire screen in front of any fireplace to protect from popping embers. For wood stoves, if you have young children, people with poor balance, or pets, always employ some sort of barrier to guard again burns from accidental falls.


Marilyn Pribus and her husband live in Albemarle County near Charlottesville. Much of their winter heat is provided by a freestanding Jotul woodstove installed on the brick hearth of the fireplace used by the former owners.

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