By Barbara Kessler
Ah, winter. Time to curl up with a book, sip hot cocoa, snuggle before a toasty fire — and watch it suck the warm air out of the house faster than a Blue Norther blasting through an open window.
It’s true, unfortunately. That wood fire crackling away in your typical open fireplace – the sort that’s been built into the majority of suburban and urban American houses — is mostly decorative. Its heating properties are nearly illusory. Sure it is warm standing right next to it, but while it burns and smolders down it operates mainly as an energy drain, fueling itself from the air inside the house and sending it up the chimney in smoke.
The heat gain from the fire might be 10 percent as some of the warmth pushes into the surrounding room. But if you leave the damper open for the evening to assure that the fumes from the embers escape, you’ll lose that gain and then some.
It’s no secret, this abysmal heat performance by fireplaces. The Department of Energy (DOE) calls fireplaces “energy losers” unless they have been specially equipped with high-efficiency energy inserts, house an EPA-rated wood stove or pellet stove or have been replaced by an energy-producing masonry heater.
“Traditional fireplaces draw in as much as 300 cubic feet per minute of heated room air for combustion and then sent it straight up the chimney,’’ reports the DOE’s consumer energy website.
Woodheat.org describes this phenomenon as a “clash of technologies ” between modern homebuilding and traditional fireplaces: “In a house that is to be tightly-constructed and well-insulated so it will be cozy and easy to heat, the home buyers want to have a traditional open fireplace, a device whose design was state-of-the-art a couple of centuries ago.”
People working in home heating and building trades know this sooty little truth about fireplaces quite well. A family would be “10 percent better off if they built their fire in the front yard and looked at it from the window inside,’’ says Jerry Frisch, owner of Lopez Quarries in Everett, Wash., a longtime builder of masonry heaters, which burn wood like fireplaces but do so much more efficiently.