Do fireplaces really make the house colder?

I have read that using a fire place actually makes your house colder because so much heat escapes from the chimney. I find this a bit hard to beleive. Before electric heat most house had fireplaces and they probably would have noticed eventually that te house was colder. So are fireplaces really counterproductive?

yes they are. no they aren’t.

an open front fireplace can loose heat up the chimney and cause air infiltration while burning. also there is some heat loss while not in use.

a glass door fireplace with external combustion air doesn’t have those problems and can be a useful heating device. if the glass door is air tight then better still.

I would say that a fireplace can make a house colder, depending on the placement of your thermostat.

We used to own a large house with a nice big fireplace in the living room. The thermostat was located such that is would sense the elevated air temperature from the fireplace, and shut off the furnace. The rest of the house would gradually cool down through the course of a cold evening, until the fire was doused or the heat was manually turned on at the thermostat.

We would also get drafts down the chimney, so there was no doubt some heat loss when the fire was not lit, but I don’t think it was enough to make the house colder; the furnace could compensate.

Even with glass doors closed (and no fire) there can be great heat loss through the large area of bricks. When we hung a painters drop cover (plastic sheeting) over the fireplace when painting it was scarry how the plastic clung to the whole hearth, not just the glass door area.

One must also remember that back in the day when fireplaces were the only sourse of heat in the house (there may have been a fire place in the bedrooms also), but any heat was better than no heat. Heat in the homes 24-7 during cold weather is actualy a new thing. When I was young the house was cold in the late night and freezing cold in the morning. Same thing for my wife, the oil pot stove was re-lit each morning. Of course there was no indoor plumbing to worry about, as we had to walk the path:o.
In Japan heating appliances are turned off at night as a rule today. It is a fire prevention rule. (so I am told).

We have a fireplace and when not in use the damper in the chimney is closed and the glass doors as well. I have not noticed a temperature drop in the rest of the house when there is a fire burning. The room where the fireplace is can reach over 80 degrees in the winter with a good fire blazing and the doors open. It is very good for heating the family room but has virtually no effect on the rest of our house. Oh, the brick wall can get so hot it is painful to the touch.

This short clip of our fireplace burning last year was my first attempt at a You-Tube video.

Mythbusters did this experiment for one of the holiday specials. I can’t find a reference, but I remember the conclusion was that yes, a fireplace does make the house slightly colder.

The biggest problem with an open fire place is that it gets its air supply from the (presumably) heated air in your house and so for every gallon of warm air that gets sucked into the fire, another gallon of cold air comes in and has to be heated by your furnace. Combined with the fact that a “modern” fire-place as we think of them today radiates very little heat back into the house, yes in most houses a fire place will make your house colder.

If you’re really serious about heating with wood you either get a wood stove that sits in the middle of the room and has a metal chimney, which greatly increases the amount of heat being radiated into the house and/or you have a sealed fire place which gets it’s air supply from outside. If you’re really serious about it, you have a wood (or coal) fired central boiler system where the fire heats water which circulates to radiators in your rooms.

The classical Santa egress style fireplaces have never been a serious heating method. Even back in the pre-electric heat and pre-automated furnace days, they were used much as they were today-- for ambiance and possibly to make a single room extra-toasty-- and the day-to-day heat source would have been something else.

And earlier today as I was reading this thread, the room (furthest from the fireplace)was feeling chillier than it should. I found the flue gate open on the fireplace. They don’t call it “The terrible two’s” for the little ones for nothing:dubious:
My fireplace wasn’t set up for outside air. I now use the cleanout as my air intake. I made a small grill to fit in the cleanout hole and it works great. No need to use the louvers under the glass doors.

if you really wanted to get the most out of a fireplace you would really need to find a use for all that heat blasting out the chimney. I built a sort of fireplace for a propane heater some friends and I use fairly often, the original design is a thin walled metal cylinder about 3 feet tall and maybe 1.5-2 across. it has intakes in the bottom and at the top its sealed with cuts around the edges, so basically it would just pump heat straight to the roof.

I took a bunch of cinder blocks and built a sort of fireplace around it and added bricks at the top, now it heats up all the bricks (well not the ones close to the ground) to a very toasty hot (we sometimes cook on the thing) add a fan above to also push the heat down and its a massive massive improvement in how well it works.

next I am going to add a couple more layers to the top, so it has even more bricks to distribute the heat.

those metal walled wood/pellet stoves rock but you could get even more out of them if you routed the chimney through something that would retain heat better and you could add something to the top to also store more heat.

It’s only tangentially relevant to the OP, but I wanted to mention that in the Tom Wolfe novel A Man In Full, the protagonist wants to impress his dinner guests with his giant fireplace, despite the fact that the temperature outside is in the 60s, so he attempts to artificially make it cold by turning down the air conditioner all the way. There’s this whole ridiculous internal monologue about the “epic battle between the fireplace and the air conditioner.” A hilarious episode in a hilarious book.

The average house temp, measured in local zones, will drop overall.

This is where averages deceive and why you should know how to use and interpret data.

The area near the fireplace will be hotter/warmer, when in use, than it would be otherwise. So, a fireplace can warm you up, but might leave other areas of the house cooler. The whole house average drops, but if you want to be warm, you can’t beat the anomaly of heat called the raging fire, which causes a localized spike in temps that has its benefits.

So, it would be stupid to be facing a very cold home and determine, “Hey, this whole house is gonna be colder if we use the fireplace, so let’s skip it.” If you are cold and in need of warmth, or simply desire it, crank up the fireplace for a blast of local heat unmatched by a furnace. You aren’t interested in poorly used stats at this point. You want a hot/warm area and you want it now. Your near-frostbitten feet and wet/cold shoes and gloves don’t care if the rooms on the other side of the home are going down a few degrees.

Hope this helps.

I have a wood burning fireplace. It uses outside air for combustion and I have an electric blower fan that pulls air in, up and around the insert and blows hot air out the top.

My house gets warmer.

Agree that fireplaces have been shown to cool down houses due to pulling outside air in.

However, historical use of fireplaces makes more sense for heating. The farther back in history we go, the draftier the houses get. If your hovel is already permeable to cold outside air, the fire produces lots of heat and just draws from what’s already drafting through the hovel.

Modern houses are virtually air tight when they’re in good repair, with lots of insulation, windows, etc. so the extra cold air drawn by the fire represents a real downside.

i would think that if the house was quality and you didn’t get the absolute cheapest fireplace option that it would not draw in air through the house. modern fireplaces have doors and use outside combustion air. a quality fireplace insert (metal box that can fit in wood or brick opening) can have an air tight door and external combustion air so that no air goes from your house into the fireplace. there are also forced air ducts around these which can heat a number of rooms.

I have a decorative fireplace, i.e. a wood-burning fireplace that’s not air tight. Sure, it has glass doors, and it has a fresh air intake, but that’s about it.

Also, I have a programmable thermostat that keeps track of the furnace run time. I can categorically state that the furnace runs for approximately the same amount of time on similar days, whether or not a fire is lit.

Therefore my conclusion is that overall the fire is neutral regarding the heating of the house, in fact wood isn’t free so it actually increases the heating bill somewhat. However, the room in which the fire is burning is magnificently warm and cozy and well worth the additional effort and cost of wood.
Since installing a wood stove in the basement years ago I haven’t used the decorative fireplace. The woodstove has cut the furnace run time by 2/3.

I lived in a house built in 1848 that had four working fireplaces which I used a lot (I’m a borderline pyro :slight_smile: ). A couple of points:

  1. As already mentioned, a fireplace will warm up the room it’s in but make the rest of the house colder. When fireplaces were the only source of heat (like my house when it was originally built) you didn’t worry about making the rest of the house colder.

  2. Most people are familiar with modern fireplaces, built after fire codes went into effect. They are deep with a fairly large chimney. They don’t radiate much heat into the room and a lot of air goes up the chimney. Fireplaces built to actually heat a room are much shallower with a smaller draft. The fireplace in my bedroom was practically in the room itself. It took some time to learn how to build a fire so that it drafted properly up the chimney and didn’t smoke out the room. Once I figured it out the fire dramatically raised the temperature of the room, much better than a modern fireplace. One of the charms of owning an older house.

What I don’t understand, however, is why modern fireplaces don’t have an opening in the back that brings in air from the outside. That way it’s not pulling air from the rest of the house.

The traditional fireplace is why Franklin invented his stove, I’m sure. A heat source that radiants all 'round, continues to radiate heat when the coals are banked, and has no open front. Our last house had a fireplace that was poorly designed and leaked copiously. We replaced it with a direct vent gas unit.

They do. All modern fireplacers I know of (including my 20 year old one) have an optional air kit that allows you to bring fresh air in from outside. Kind of like a dryer vent to the outside.

Where (in the fireplace) is it located? My condo doesn’t appear to have a vent, nor my parents’ home but being the typical male I’m not good at finding things.

Well that’s not true. The house I grew up in (and still live in) had no central heating when it was built in the 1960s - we just had the open fire in the lounge and some plug-in electric heaters to put where we needed them upstairs.

We use the open fire most days in winter, and it certainly doesn’t make the house colder - it throws out a surprising amount of heat and can actually be uncomfortably hot to sit in front of once it’s been going a few hours.

Then again, we don’t have a “furnace” trying to heat the fresh air that is being drawn in by the fire, so YMMV.