Page 12 RAIN November 1980 Turn Your Fireplac Just in time for winter, Bill Day's popular Consumer Guide to Woodstoves has been revised and is going to press right now. New features include this article on fireplace retrofits and an article on wood furnaces, plus there is up-to-date information on wood heaters, cook stoves, woodstove installation and repair, chimney care and maintenance, wood energy resources, and everything else you need to know about heating with wood. Don't wait for snowturn to the order form on page 23 and stay warm! by Bill Day Many efforts have been made over the decades to improve fireplace efficiency. They range from the "Rumford" design in masonry fireplaces to prefabricated steel air-circulating units, and a wide variety of heat exchangers intended to sit in an existing fireplace cavity. At best, the efficiency achieved by these techniques barely approaches 50 percent of the efficiency of the average free-standing woodstove. Heat loss due to excessive air infiltration can be reduced by adding glass doors to the face of your fireplace. When the fireplace is in use, the glass doors should be opened so that radiant heat is not deflected back inside the fireplace cavity. Glass doors will not contribute a positive gain in efficiency to a fireplace, but they can prevent a fireplace from becoming a heat loss factor in your home. One of my greatest concerns with fireplace accessories is the lack of safety and durability in fireplace heat exchangers. These units are usually constructed of steel tubing, either round or square. The rate of deterioration of the tubing, which often doubles as a wood grate, is usually pretty rapid. If the unit includes a fan, failure of the fan motor or a temporary interruption of electrical service can greatly accelerate deterioration of the tubing. Eventual result of tube failure where a fan is involved is a spray of hot ashes and embers onto the home carpet. I recommend avoiding heat exchange contrap2 EXAMPLE A STOVE tions constructed along these lines. Another way to utilize an existing fireplace is installation of a fireplace insert in the fireplace cavity. A significant disadvantage of this approach is that chimney cleaning is made very difficult or virtually impossible without complete removal of the unit from the fireplace cavity. Some inserts are advertised as perman,ent installations, designed to be bolted into place. Chimney cleaning is a regular and necessary maintenance chore which should not be hindered or discouraged. I also have yet to find a fireplace-stove insert on the market incorporating the necessary features for efficient wood combustion. Glass windows usually leak air, and steel doors and doorframes are likely to warp (leaking more air), etc. If there is a choice, I would recommend avoiding these ill-conceived devices. The use of an existing fireplace chimney as an exhaust vehicle for a free-standing stove is the most promising of all fireplace retrofit ideas. But bear in mind that the fireplace chimney, when used to exhaust a woodburning appliance, will require frequent cleaning. The typical masonry fireplace flue is significantly oversized for the modern airtight stove, and provisions must be made for easy and frequent chimney cleaning to remove the predictable creosote deposits that will accumulate. EXAMPLE B STOVE NOT ALLOWED
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