Fireplaces That Can Heat Your Home and Cook Your Meal
By John Vivian
Remember back in 1970-something when one of the Nixon daughters led a TV tour of the White House in steamy Washington, D.C., and innocently reported that "Daddy likes to turn up the airconditioning and have a fire in the fireplace"? Gasoline prices had just been oil-embargoed through the roof, taking home heating and cooling costs right along with them. For those of us who didn't have taxpayers to foot the bill, that off-the-cuff admission was particularly galling and further alienated the rebellious, draft age, newly environmentally sensitive 'Nam era American youth that I was at the time. Nearly everyone, even our esteemed leader, considered the living room fireplace more a source of entertainment than serious home heat. Well, he learned his lesson.That's an almost forgotten and largely forgiven era. Richard is history. (Along with your squandered youth and mine — right, dear reader?) Besides, with the advent of wood-burning stoves in the late 1700s, the open fire that had warmed and cooked for mankind since the dawn of time was relegated to Boy Scout camp-outs. And the traditional fireplace/flue complex lost its utilitarian value and became a component of design and decor, a fixture in house architecture, an excuse for a mantle and a mirror or painting; it was no longer the home's central source of light, motion, and warmth.
Today, a typical fireplace has a low, deep firebox and large throat (the opening between firebox and flue) and is designed primarily to evacuate smoke, even when the fire is newly started. At a full, roaring blaze it radiates only 10% of the heat energy contained in its fuel out into the room — just enough to give the effect of a cozy, toe-warming fire and take the chill (natural or artificial) off a room. The rest of a fire log's rich concentration of sun-energy is lost up the flue. Along with the smoke goes (fossil fuel heated) room air that must be continually replaced by cold outside air, reducing the heating effectiveness of the fireplace and creating chilly drafts.
Fire in an Open Box
Very early American fireplaces, based on an English model unchanged since the Dark Ages, were primitive and inefficient — little but a hood with a pair of side jambs and a smoke hole located somewhere along the top. The flue damper wasn't invented till Ben Franklin dreamed it up in the mid-1700s. To keep warm air in and keep cold air from streaming down the flue and into the room, a cold fireplace was closed off with a not-very-effective stove board. Many colonial fireplaces consumed 10 or more cords of wood a winter. Householders stayed as warm as they could by bundling up, sitting on benches inside the huge walk-in kitchen fireplace (the "inglenooke" in Chaucerean Middle English), or huddling in front of a small parlor fireplace, benefiting only from the little heat that managed to radiate through the up-roaring draft that was being pulled in from behind them. People roasted in front and froze in back unless they wrapped in blankets or sat in high-backed settees.
An Earlier Energy Crisis
Ben Franklin knew that inefficient fireplaces made the colonies dependent upon English coal.
1700 to Present
It wasn't easy to experiment with heating appliance design in the early days. Each fireplace was a permanent installation requiring tons of masonry and a house. An experimental fireplace/flue combination that didn't work had to be torn down and re built... So, change was slow.
Early fireplace builders followed one rule: a small fireplace should be taller than wide, a large one wider than tall. So in colonial homes, you'll find big old walk-in cooking fireplaces filling most of the wall of a kitchen and smaller, high-backed heating fireplaces in other rooms. Fireplaces on second stories were smaller than those down below and used smaller vents into common flues, so as not to overpower first-floor fires that had farther to draw to exit the chimney. Still, each home owner or mason was his own expert; firebox dimensions and flues often followed inefficient, snaking paths through house walls. Fireplace-to-flue-openings and flues themselves were universally larger than efficiency would suggest. With smoke-detaining, rough walls, they had to host one or more chimney sweeps — small boys, for the most part, who were sent climbing up the whole length of the flue plying their brushes.
The fireplace was more than a heating and cooking appliance; it was and remains central to the design of the home. In warm southern climates, chimneys gravitated toward the end walls of the house — culminating in the classic brick double-ender with four flues serving fireplaces at corners or in end walls of the four main rooms on the ground floor and with smaller fireplaces in rooms above. In chilly New England, the farm home was built in stages. First was a one-room cabin with a combination cooking/heating fireplace making up most of one end wall. In step two, a second room — a mirror image of the first — was built with a second fireplace backing up to the first, and exhausted by a second flue. In stage three, a pair of rooms was built behind the first two, heated by warmth radiating from the heat sink formed by the brick of the fireplaces forming their interior walls. Finally, a third large, cooking fireplace with its own flue was added at the rear of the original dual flue and a lean-to summer kitchen addition was built on. A low second story was added, and small upstairs fireplaces were plugged into the original dual flues. Thus appeared the colonial center-chimney saltbox home with its characteristic broken roof line at the rear.
Settlers from Germany brought over the early iron-plate heat exchanger — a four-plate closed box protruding into the room and mortared into a flue located on an outside wall. The fire stove got its air and fuel from outside. The iron radiated heat into the room more effectively than brick, but unlike the English-style open fire, it did not afford a view of the flames or evacuate room air. Farmhouse rooms became stuffy (to put it politely), as many early homes backed onto the winter animal pens and the four-legged occupants contributed their unique body heat and odors to the home.
