ON COLD winter weekends like this one, I long to curl up in front of a roaring fire. Theoretically, I would do this to warm up. An open fire, with logs blazing, is after all, a source of considerable heat. The trouble is that much of this heat goes up the chimney.
I found this out when I looked into the science behind the romance of the blazing open fire. I wish I hadn't. There are some bedrock beliefs that are best undisturbed. For me, one of them is that burning chunks of wood in an open fire is a good way to heat up the house.
Sadly, the facts show that's probably not the case. "Open fireplaces, while pleasant, are not efficient heating devices," said a technology assessment Web site of the Louisiana Department of Natural Resources. Fires in conventional masonry fireplaces and older prefabricated fireplaces are about 10 percent energy efficient, the Ace Hardware Answer Page told me.
Other sources of fireplace facts warned that once the fire burns down to smoldering embers, you can actually lose heat. Bummer.
It is bad news, but it makes some sense. The fire needs oxygen to burn, and pulls air from the room to replace the air going up the chimney as combustion occurs. The fire also sucks cold air in through any holes in your house. Older houses have plenty of holes and every home has doors and windows.
I have often boosted a struggling wood fire by opening a window near the fireplace. This meant I was letting cold air into the house to help start a fire I was igniting to heat the house. Life is full of contradictions.
Opening a window on a winter day usually causes your furnace to kick on and compensate for the sudden heat loss. This explains why, according to energy- efficient experts, recommended steps to take before lighting a fireplace fire are to turn down your home furnace thermostat and shut the doors of the room that houses the fireplace. Again, this strikes me as counterintuitive, turning down the heat to warm yourself up. But I can live with it.
The real culprit in terms of heat loss, I learned, is the traditional open-burning wood fire. All fireplaces are not created equal and the ones that make the energy-efficient experts smile are newer, sealed-up units.
The more sealed up your firebox is, the better it is at generating, not eating, heat. The new generation of fireplaces, like most upstarts, is much tighter than its flabbier predecessors. Newer gas-fired fireplace inserts hold the heat better and score much higher in efficiency, as high as 70 percent, according to industry sources. But for me it lacks the atmospheric sizzle of the open hearth. Looking at a gas flame through a plate of ceramic glass is not the same soul-stirring experience as sitting in front of a crackling wood fire.
I recognize that life is full of tradeoffs. For example, I have friends I like to visit on cold winter weekends who have a gas-fired log in their fireplace. It looks like real log, at least after the second glass of wine. It gives you a warm glow, I am told, until you get your gas bill.
I learned that wood burners can improve the efficiency of their fireplaces by installing tight-fitting glass doors. The doors remain open when the fire is at its aesthetic, heat-producing peak, then are shut tightly when the fire wanes. This allows fumes and smoke to go up the chimney and out the open flue and also blocks cold air that rolls down the chimney.
There is another way to look at the practice of burning wood in an open fire. Rather than viewing it as a source of heat, the fire is seen as a source of warm mental comfort in a cold world.
I am attracted to this view, and apparently so are a number of folks in the Baltimore area. Last weekend, as a snowstorm hit, people started buying firewood at Watson's Fireplace & Patio in Lutherville. By mid-afternoon Saturday, all of the wood, the equivalent of two cords, was gone - sold in $15 "weekend burn" packages. Steve Watson, the store manager, had buttoned up his business and sent the staff home.
"There is nothing like the crackle and pop of an open fire," Watson said yesterday as he looked forward to coping with another winter weekend. "In this world today, sometimes you have to kick back, and burn a fire."
I agree. A key to making it through a Maryland winter is learning to appreciate a roaring fire without doing the math.