Aaah! A crackling fire. How cozy. How romantic.
And, alas, what a waste. Although the room feels toasty, the chimney spews out heat indiscriminately.
About 90 percent of the fire's warmth heads up and out, along with some of the heat generated by your furnace.
A conventional fireplace also doesn't promote complete combustion of the wood, no matter that the logs eventually turn to ash. This can exacerbate air pollution both indoors and outside.
The nasties include carbon monoxide, nitrogen oxides, and fine particles that can aggravate asthma and other conditions.
For these and other reasons, fireplaces are well worth our consideration. Half of all homes in the United States have either a fireplace or a freestanding stove. Fireplaces are one of the top three features people want, says the National Association of Home Builders.
And they can really cast a pall over things.
Andy Palmer was thinking about some of this when she contemplated the handsome stone fireplace at her retirement village, Kendal-Crosslands, in Kennett Square.
The place is a bastion of green. They've switched out their bulbs. They have a sustainability ethic. They're building new cottages certified to the greenest industry standards (no fireplaces).
But when Palmer, who has worried about climate change for some time, thought about that roaring fire in the public room, she was troubled.
She put out a query on a regional sustainability list-serve, and boy did she get a lot of hot tips.
Comments included everything from practical advice to technical dissections to philosophical musings about environmental justice and our "capitalist oligarchy."
Fireplaces do serve their primary purpose. Somewhat.
A few winters ago, Marc Brier, a park ranger at Valley Forge National Historical Park, kept a fire going in one of the log cabins for several days.
He wanted to show that, despite the privation and hardships, Washington's army in 1777 was resourceful and resilient. And, occasionally, warm.
After three days with a fire in the 14-by-16-foot cabin, the temperature by a wall near the fireplace was 70 degrees, and the dirt floor had thawed. It was 31 degrees outside.
The problem is that fireplaces just don't work well enough, especially not for a world so different from two centuries ago.
There are many options, if no easy answers. Much can depend on what kind of fireplace you already have, which will determine whether or what kind of changes you can make.
Something as simple as a fireplace door can reduce the flow of air into the fireplace - and then up the chimney.
One option is to give up on wood. Get a gas fireplace insert. Many of these are 80 percent efficient and generate little pollution.
(A caveat: For this and other options, the pollution refers to that generated at the source. Many are concerned about the environmental effects of natural gas extraction, for instance.)
The U.S. Environmental Protection Agency recommends that if you stick with wood, you select an EPA-certified device - its latest list includes 887 models - and follow its best-burn practices.
Common options include a pellet stove, a freestanding woodstove, and a fireplace insert.
They have many features that differ among types, manufacturers, and more. But if green is your goal, one thing to look for is the emissions rate, expressed as grams per hour.
EPA-certified wood stoves generate no more than 7.5 grams of particulates per hour, compared with 15-30 grams for older models, and as much as 60 grams for a conventional fireplace.
Some of the fireplace inserts have catalytic combustors. Pull a lever, and a fire's leftover gases are burned in a separate chamber. EPA-certified stoves of this type emit a max of 4.1 grams of particulates an hour.
Pellet stoves, which burn compressed wood and plant waste, pollute even less. Pellet stoves don't require certification, but some manufacturers voluntarily seek it.
Another thing to look for is the efficiency, often expressed as a percentage. The EPA assigns some devices a default efficiency rating - 63 percent for noncatalytic stoves, 72 percent for catalytic stoves, and 78 percent for pellet stoves.
For my own fireplace, I opted for a catalytic woodstove insert maybe five years ago. I can't say whether this was the best choice for my house - it was pre-greening for me. But it fit the space and it works.
It's basically a metal box with a glass door that fits into the fireplace and extends maybe six inches in front.
Since we live on a wooded property, we generate nearly enough renewable fuel on-site.
The insert's big steel shell radiates heat back into the room. I like how it keeps the room where we spend most of our time warm.
The other night, when the temperature outside was 28 degrees, the air 16 inches in front of the insert was 97.8 degrees.
Four feet to the side, I dislodged the cat, Charlie, from my armchair and found the temperature a balmy 71.4 degrees, far higher than we keep the thermostat.
One drawback: An internal fan that shoots hot air into the room makes an industrial racket worse than my fridge.
In the end, though, I'd rather listen to that than be chilly and breathe smoke.
Charlie, too, probably.
GreenSpace: Tips for Better Burning
The EPA's "best burn" practices:
Dry firewood six months and keep it dry. Wood burns best when moisture content is less than 20 percent.
Don't burn cardboard, plastic, painted wood, pressure-treated wood, driftwood, diseased wood.
Burn hot fires. Regularly remove ashes.
Close damper when not in use.
If you're thinking about changing from an open fireplace:
Investigate pellet stoves and gas or woodstove inserts. All have pros and cons for different needs.
Purchase an Environmental Protection Agency-certified appliance.