Wood types affect efficiency of fireplace

Dear Jim: I installed an efficient wood-burning fireplace in my living room this summer. I am ready to buy some firewood. Is there much difference among wood types? And how can I tell good wood from bad? – Connie F.

Dear Connie: Now that you have your new fireplace, it is important to select the proper types of wood for the greatest heat output, efficiency and enjoyment of the fire. Before you buy firewood, check the fireplace specifications for the maximum length of log it can handle.

There are significant differences in the burning qualities of various types of firewood. For example, the heating value of a cord of firewood can vary from a low of 12.5 million Btu for aspen to a high of 24.6 million Btu for shagbark hickory. These values are for air-dried wood with a moisture content of about 20 percent. Green wood contains about 40 percent moisture.

Burning most air-dried woods produces about 7,000 Btu of heat per pound, so heavier, more dense wood provides more heat per cord. If you cannot tell what type of wood it is by the bark, color or grain, pick up several pieces to determine their relative weight. The differences will be noticeable.

Knock several pieces of wood together and listen to the sound. Dry wood makes a sharp ringing sound. Green wood makes a dull thud. Look for checks, cracks and a dark color on the log ends as indications it is well-seasoned and dried. Shorter logs also tend to be drier because most of the moisture escapes from the ends of logs, not from the exposed split face.

Most of the firewood you select should be hardwood. These are generally heavier and burn much slower and cleaner than softwood. In an efficient fireplace, which controls the amount of combustion air, clean burning (low creosote buildup) characteristics of the firewood are important. A dirty-burning fire can result in a dangerous chimney fire after a long season.

Also buy some softwoods for starting the fire. With the higher resinous content in softwoods such as pine, fir, cedar and spruce, these woods light easily and create a hot fire ready for the hardwoods to be added. The resins in the softwood actually create extra heat. Fruit and nut trees also burn quickly and give off a wonderful aroma similar to the fruit or nut.

There are also other factors to consider. Some good-burning hardwoods, such as oak and elm, are difficult to split. I use an axe, maul and wedge to split most of it. For more difficult types or large pieces with branches, a hydraulic SwiftSplit (www.swiftsplit.com, 800-366-6268) log splitter does the job. It handles logs up to 20 inches long and a foot in diameter.

If smoke from the chimney is an issue for you or your neighbors, avoid burning elm, sycamore, gum, aspen, basswood and most softwoods. Many of the softwoods also pop and throw sparks as they burn, so be careful when adding the hardwood to a just-started fire of softwoods.

Dear Jim: I had a problem with night sweats during summer. To save electricity, I tried using a fan so I did not have to set the air conditioner lower, but it did not help. Are there any other efficient options? – Amy Y.

Dear Amy: Circulating air from a ceiling or floor fan helps somewhat, but the sheets and covers reduce the cooling effect. Try sleeping without a sheet or use one with an oven weave to allow the air to reach your skin.

There is a new fan available that is mounted under the end of the bed. It directs air between the sheets and over your skin. The Bed Fan (www.bedfan.com, 210-632-8280) uses little electricity and has a speed control near your pillow.

Send inquiries to James Dulley, Bangor Daily News, 6906 Royalgreen Drive, Cincinnati OH 45244 or visit www.dulley.com.