Sunday, April 20, 2008

Quickie: Fireplaces and Stoves

Source: Creative Commons image on Flickr by Adam Melancon

Do you have a fireplace in your living room or study? Do you use it regularly for heating? If you replace it with a modern stove, you won't have to cut as much wood, but you'll still be warmer than before. But what if you want to heat more than just one room with a wood stove? Most people I know who use wood heat do have modern stoves, but their warmth is mainly provided by radiation.

First, a little science: There are three types of heat transfer. Conduction is where heat is transfered between two things that are touching. This is not something you want to do with a stove, it burns. Radiation is where energy travels in waves through space and hits an object. This is how you feel the heat of the fire, it is also blocked by any solid object. Convection is where heat travels through the air by an air current created by the different densities of hot and cold air. Convective currents can travel around corners.

If you want to heat more of your house with your wood stove, you need to get the convective currents moving. The best way to do this is with fans. Ceiling fans that reverse directions for summer and winter use are great for this, but another valuable and inexpensive product is a stovetop fan that is powered exclusively by the conductive heat of the stovetop. It's called the Ecofan. It comes in three models and starts around $100. It moves 100 cubic feet a minute (CFM) for the smaller model and 150 CFM for the larger model. It really does make the whole house more comfortable.

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