alt Hacker NewsWhen we lost power for 10 days a few winters back we attempted to use the fire place for heat. It was a fail. Post and beam house (large wide open floor plan) with a large transfer from 1st to 2nd floor, and apprently my lack of skill for optimizing heat over beauty in the fireplace, left us without much of a thermal bump. To this day I swear we were pulling heat out of the chimney faster than we were heating the house; I cooled the house with fire.
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That’s not uncommon, but having grown up in a house heated by wood fires I knew that when building our current house. The main fireplace is on a central wall and has enormous thermal mass. Beauty and utility can be combined.
To use it effectively you want one with water jacket and just use that hot water with your normal house heating system. You don't need much power to run circulation pump so UPS + some solar panels should be enough even in deep winter. There are also systems that get it out of the exhaust but that doesn't get you much heat storage, just instant heat and generally less efficient.
Old school version of that were masonry stoves that come with ton+ of mass for the bricks and smoke being routed all over (often including a place to sleep) to take as much heat as possible from it.
If I had money for that I'd put a big hot water tank for buffer, heat it normally with heat pump, and just had emergency water-sheathed fireplate, with big buffer you can just fire it up once and have tank slowly give the heat back to the building. Or fire it up at the coldest days to save some heat pump power in days where there is barely any solar.
I know someone who gets through the winter off their fireplace. Really old timber house with riverrock chimney. Their fireplace looks nothing like what you think of a fire place looking. You can’t see the fire, there is like this big iron door in front of it. They go through a huge pile of wood every winter, along with a couple electric heaters for rooms or office.
I assume most decorative fireplaces on the other hand are not built to heat the house.
It's pretty much 10 to 20% efficiency for an open chimney and 80% for a good wood stove so your result isn't surprising.
Open floor plans also destroy the efficiency as the heat goes up which made your already inefficient heating even worse.
Combine both together and you probably have 5% efficiency.
Yeah fireplaces don’t make sense to me. Hot air rises and it sucks the existing heated air in the house which all flows out. The only way to heat the space is you need something with a lot of thermal mass that heats up in the process and then radiates heat. So a lot of bricks around the fire, some sort of baffle to enable the heat transfer and a system that sucks in air from the outside.
Yeah, if you actually want to heat the house with fire you’ll want an insert or a wood stove. Otherwise most fireplaces in most houses are decorative, and one pays for that decoration with heat loss.