Aaahhhh! There's nothing like sitting by a warm fireplace on a cool crisp evening, all wrapped up in a fuzzy blanket with some hot cocoa or cider in your mug! Winds howling outside can just stay there; however, part of remaining snuggly warm has to do with eliminating that nasty draft from around the doors and windows due to the fire eating the oxygen in the room and sending it up the chimney.
Fireplaces are usually considered 90-95% inefficient. Suffice it to say, they are one of the worst ways to heat a home; however, sometimes the lure of watching the fire is too much to abstain from. How then, do we make burning wood for heat more efficient?
There are three ways to improve the heating capabilities of fireplaces: design, placement, and fresh air delivery. Additionally, there are a few other options to taking an existant fireplace and making it slightly more efficient that I will mention, but first, let's start with the fireplace itself...
#1 - DESIGN:
Build a better fireplace! Although a masonry stove fireplace is the most efficient due to having a second burn chamber (these are massive, labor intensive to build, and are typically found only in Europe), they can be quite expensive, so to keep in accordance with standard sizes and cost, I recommend a Count Rumford fireplace!
The Count Rumford design is different than a standard fireplace because the design of the firebox and opening is different. This allows the fire to throw more heat into the room via three ways:
1. The firebox is shallower than a standard fireplace, placing the fire closer to the front (nearer to the room).
2. The opening at the top of the fireplace is slightly higher than a standard fireplace, allowing the smoke to crackle and burn off some of the impurities in the smoke, which gives off extra heat.
3. The back of the firebox is angled at the top to reflect more heat into the room.
#2 - PLACEMENT:
Put the fireplace inside, not outside of the house!
Most fireplaces are built backwards from what they should be, with the brick chimney on the outside of the house. Bricks provide thermal mass, which warms up and gives off heat... but in a traditional fireplace all that heat from the brick is being lost to the outside! Why would we want to warm up the forest, or our neighbors, when the idea is to warm up ourselves inside our house?
A properly built fireplace will have the chimney not only on an interior wall, but it will have the thermal mass (whether it is brick, stone, etc.) exposed so the heat can transfer to the surrounding room(s), which in turn reduces heating bills, and keeps the home more comfortable.
#3 - FRESH AIR DELIVERY:
Bring in fresh air to feed the fire!
Fires consume oxygen to burn, which means it is sucking air to feed it from within the room. The heated air then goes where? Straight up the chimney to the outside! This is one reason why fireplaces are so inefficient; so much hot air is lost to the outside while it is pulling cold air in from the outside.
Instead of letting a fire suck air from around the windows, or a slightly-opened window, underneath doorways, and so on, bring tempered (gently warmed) air in through an earthtube.
An earthtube is a 100-foot long PVC pipe that runs 6 feet deep underground that has an intake and outlet for air. Cold winter air enters the intake, travels through the earthtube and is warmed by the earth's stable temperature underground, and exits the tube near the entrance of the fireplace (usually on the floor near the fireplace opening).
The result is pre-tempered air that feeds the fire instead of pulling cold drafts from around the room, thus making the fireplace more efficient!
The good news is that earthtubes also--and primarily--are used for cooling the house in summer, provided there is at least one earthtube in place per room of the house, but one single earthtube is all that is needed to feed a warm fire, and keep the room(s) in your house more cozy!
There are a few more ways to make a fireplace more efficient, which include adding a fireplace back to reflect heat back into the room, use a damper, put fireplace doors on (to stop excess drafts from exiting up the chimney), and using a blower to force the heat into and around the room.
Another way to make a fireplace more efficient is to put in a woodstove insert. Woodstove-fireplace inserts are more efficient than standard fireplaces and can be fueled by electricity, propane/natural gas, wood, pellets, or coal. They can even have a front door with a window so you can watch the fire as in a traditional fireplace.
Some people choose to eliminate fireplaces and chimneys altogether and install an efficient woodstove in it's place (instead of a woodstove insert). This way the entire firebox is in the room (as opposed to in the wall) and they radiate heat into the room far more readily; additionally, EPA certified wood stoves are 50% more efficient than old style woodstoves.
Earthtubes can also feed tempered air to woodstoves and help with heating efficiency.
If you want to learn more about how to make earthtubes please see my article called COOL AND HEAT YOUR HOME WITH EARTHTUBES online at sunstarangel.blotspot.com
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