***“He and his wife eat dinner by candlelight and have a fire going in their fireplace – even though he is aware that it actually results in a loss of heat.”
If there is any message here, it is that it’s time for a generator***
What the *&^%$?
I guess our ancestors all died of hypothermia without those generators then huh?
Where did this guy GET this dumbass idea and why is the reporter parroting it as fact?
Fireplaces require oxygen. And, as a result of the combustion process, quite a lot of warm air goes shooting up the chimney. Where’s the air to replace that to come from? Replacement air has to infiltrate from the outside. Cold air.
So, the question is, can the heat from the fireplace warm up the incoming air fast enough to make up for the difference in temperature?
As it turns out, fireplaces aren’t brilliant at doing that because of all that warm air that’s shooting up the chimney. So the people in front of the fireplace stay warm (on one side) while anyone in the further recesses of the house freeze.
Didn’t matter in the good old days because there was no heat or much insulation in the rest of the house anyway. So the inside was pretty much the same temperature as the outside except for the tiny bit of the house people were living in. But in the days of central heating, running a fire is probably a net negative as far as heating efficiency goes.
This was, incidentally, already discussed in this thread and Mythbusters also verified the “cooling rest of the house” part of the story.
I can testify that the room with the fire in it could get pretty damn hot, and I mean the air in the room, not just the side of the people facing the fire.
I don’t know how much of an impact this is but those colonial-era homes had fireplaces and chimneys in the middle of the house, so at least any heat in the chimney stayed in the house. But most houses today have outside chimneys.
Did you know heaters don’t increase the heat energy of the air? They increase the temperature, but the air expands, and the total energy/volume remains constant.
It is worth mentioning that there is a very significant difference between an open fireplace and a slow-combustion or otherwise controlled combustion fire. The problem with an open fireplace is that the draft up the chimney becomes so strong that it exhausts vastly more air out of the house than is required for the simple act of combustion. Fitting dampers to the chimney can help but you don’t want the smoke coming out of the fire place into the room, so the system still draws a lot of air.
An iron or steel closed combustion fire can achieve very high efficiencies, for a number reasons. Most importantly the fire is only fed enough air to actually run the combustion. The closed box means that the smoke doesn’t get into the room. The closed box can be designed to provide a much more controlled path for burning gasses, ensuring much better burn efficiency, one that occurs in the firebox, and not half way up the chimney - or not at all. The firebox radiates heat, and can be fitted with a fan to circulate air over it, both significantly improving the amount of heat getting usefully into the room.
The disparity between the two approaches is about 20% versus 80% efficiency.
All houses with fireplaces always had chimneys of some kind, or the people in them would be dead. And no, the heat in old colonial era homes didn’t stay in the house, it went out the chimneys.
I have an open fire in my one room apartment, and the statement in the OP is completely accurate for the reasons mentioned above. To keep my apartment from filling with smoke I actually have to open a window in order to get enough of a draft to keep the smoke shooting up the chimney. While the area immediately close to the fireplace is nice and cozy, the rest of the apartment drops in temperature due to the influx of freezing air.
Note that when my house was built (early 1920s) isolation wasn’t really what it is today, and the ventilation was based around the fact that there would be a draft through the windows (with warm used air rising naturally up the shafts). A clever non-mechanical solution, but one that has since faltered with proper window isolation and double panes. The result of this is that many apartments in my building instead suck in air via their chimney pipes (because the apartment owners have closed all the existing vents to the outside), with hilarious results when somebody’s lit a fire.
Antidote only. We have a fireplace in our family room, in winter with a good fire going the temp can reach 80 degrees in that one room. We have not noticed a temperature drop in the other parts of the house.
It is hard to argue with well designed tests. Do we accept facts at SD or not? I have retrofitted our 1970 house to the point our air hog fireplace didn’t draw right. I cut a duct out the back of it to the garage. It draws better now and the rest of the house stays warm.
This is why the Franklin potbelly stove became such a fixture of pioneer houses. Once the technology was available to make large quatitites of heat-resistant metal cheaply, it was the preferred method of heating a house. It’s much more efficient, the fuel burns slower, does not suck as much (replacement) cold air in, and in many instances the chimney pipe runs across the ceiling to heat the room more before exhausting out the roof. You can adjust the combustion level and so heat given off and fuel consumption by adjusting the air intake.
before that, people weren’t being stupid, they just did not have many options. In places like the old Roman baths, you can see where they had the floor on raised tiles; a fire in a separate room vented under the floor raising the temperature of the floor tiles and heating the room without the raft and heat loss in that room.
Yep. Fireplaces suck unless your in the same room/right in front of them. A well designed wood stove works quite well though. I heated exclusively with wood for many, many years.
Now I have a propane stove. The flue is coaxial. A pipe within a pipe. Exhaust goes out one, combustion air comes in the other.
Wow! I didn’t know you could use the word ‘coaxial’ in that sense.
Sensible once seen, but not immediately apparent.
I am going to use that usage, though I am not certain when I will get the opportunity since I don’t work in HVAC.
Thanks!
And nothing Dewey Finn posted contradicts that. He was making a distinction between chimneys whose walls are entirely contained within the house, and those whose walls border the outdoors.
The effect of seemingly small factors like this should not be underestimated. I have a friend who decided to heat his home with a wood stove. He started by placing it basically inside his very large fireplace and it was terrible. Then he got a horizontal extension to the flue pipe that allowed the stove to be moved about three feet, so it was in front of the fireplace instead of inside it, and it worked great.
Growing up, we had a wood stove in the family room and it had a double-walled stovepipe, but only where it penetrated the ceiling and roof. So in that case the double-wall stovepipe was more about making sure that the house didn’t burn down. We provided combustion air via a vent in the front of the stove.
