Green Options

Editor’s Note: This post was provided by one of our paid sponsors, Chimneyballoon. Stop heat and AC from escaping through your fireplace or woodburner chimney with a Chimney Balloon fireplace plug draft stopper.

On a cold winter evening, who of us is not tempted to go to the living room, stoke up a fire in the fireplace, and read a book in front of the hearth? You may be thinking “I am doing myself a favor by supplementing the furnace with additional heat”. But there’s a dark secret about your fireplace: you are making your house colder, and could be contributing significantly to pollution depending upon how you burn. Fireplaces can be monstrous energy eaters!

The wood burning fireplace is an “Energy Eater”

The air action that a wood-burning fireplace initiates in our home is wasteful. The second the damper is opened, heated air begins pouring out of the top of the chimney. As the fire in the hearth accelerates, the combustion process grabs already-heated air from your home and burns the oxygen and combustible gasses in it. The heat that is created in this combustion quickly rises and grabs more heated inside air and tosses it up the chimney. You can restrict the amount of inside air that the fireplace has access to by installing glass doors, but this will also severely limit the amount of radiant heat that fireplace can cast forward into your living space. This radiant heat is the heat you feel on your skin in front of the fireplace, and is the only usable heat that the fireplace will produce since the combustion heat is pouring out the top of the chimney. In the meantime the home is drawing in cold outside air from other places (i.e. windows, light sockets, doors, etc) to replace the air that is escaping the home through the chimney. This is referred to as the “stack effect.”

Author’s note: the following article on home heating is the seventh in an eight-part series. If adding thermal mass to your house isn’t realistic, another approach is to install a massive heater. That is to say, the heater contains the thermal mass your house may lack.

Clean and Super-Efficient Wood Heating
Super-efficient wood burning heaters with lots of mass are called by many names: masonry stoves, russian stoves, finnish stoves or finnish fireplaces, mass heaters. Though mass heaters may look like traditional fireplaces, they’re actually very sophisticated heating devices.

Burning wood in a mass heater doesn’t involve feeding in wood a few pieces at a time. The wood is added all at once, lit, and burned as quickly and as hotly as possible. Because of the high combustion temperature, there’s virtually no smoke. Combustion is so complete that, with the exception of a bit of smoke released when the fire is first started, most of what comes out of the chimney is carbon dioxide and water vapor.

Author’s note: the following article on home heating is the fifth in an eight-part series.

Open fireplaces have a reputation for polluting air. Actually, a fireplace, when burned hot and fast, creates very little pollution. The trouble is, a hot fire in a fireplace sometimes yields less heat than a smoldering fire. Where does the heat go?

The optimal amount of combustion air contains just enough oxygen to burn all combustible gases liberated by the heat. Any additional air grabs heat and sends it up the chimney. Under some circumstances, fireplaces can so far exceed this air-to-fuel ratio that they suck more heat out of a house than they radiate back into it. The fire actually makes the house colder!