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Yes, they do need need electricity. Source: I live in Ontario, Canada, and am currently being kept warm by one. Most (gas) furnaces are forced air, and how exa

Yes, they do need need electricity. Source: I live in Ontario, Canada, and am currently being kept warm by one. Most (gas) furnaces are forced air, and how exactly would the fan run without electricity? How do you think the thermostat runs its thermistor (and probably LCD display) without a power? The Technology Connections YT channel has a recent good overview, "Forced-air Furnaces: The What, Why, and How": * https://www.youtube.com/watch?v=lBVvnDfW2Xo https://www.youtube.com/watch?v=lBVvnDfW2Xo As for efficiency, you can get units that are 99% efficient (AFUE): * https://www.lennox.com/products/heating-cooling/furnaces/slp99v https://www.lennox.com/products/heating-cooling/furnaces/slp... * https://en.wikipedia.org/wiki/Annual_fuel_utilization_efficiency https://en.wikipedia.org/wiki/Annual_fuel_utilization_effici...

rootusrootus 6y ago
> Yes, they do need need electricity. Some do, some don't. Mine has a pilot light and a thermocouple. I used it to keep warm while our power was out for three days this past weekend.
- throw0101a 6y ago
  What's the make/model? Presumably not forced air?
  - rootusrootus 6y ago
    Not sure about make & model, I'd have to find the paperwork from when the house was built 8 years ago. It's radiant, not forced air. That's an option I could add but it would require electricity for that part.
  - frosted-flakes 6y ago
    The house I live in has two gas fireplaces, both 20-30 years old. They work in the same manner described above, with no requirement for electricity. Each one also has a blower that is simply plugged into the wall (one runs continuously, the other is thermostatically controlled; both are very loud). The blowers are optional, and the house gets adequately heated even when they are off.
- mark-r 6y ago
  I wouldn't be surprised if pilot lights aren't illegal now. They're terribly inefficient, more so if your furnace rarely lights.
  - rootusrootus 6y ago
    I think pilot lights are still pretty much standard on certain appliances, like water heaters and fireplaces. Probably deliberately so they can run without power. All my other gas appliances are electronic ignition, e.g. we have to use a lighter to start the range when the power is out.
  - frosted-flakes 6y ago
    In the case of gas fireplaces, all of the heat generated is used, so I would think it would be perfectly efficient. As long as you shut it off during the warm seasons, anyway.
luma 6y ago
I have two gas fireplaces, neither use power (nor have any available). Valves and safety is handled via millivolt thermopiles in the pilot light and main flame. Heating happens via convection through ducts that run from below to around/behind the fireplace itself, then out over the top. It passively moves a fair amount of air and can make the room uncomfortably warm if left on too long. I have no idea if this is common or not, but I know of at least two counterexamples to your statement here in Michigan.
ashtonkem 6y ago
GP said fireplace, you're talking about furnaces. Plenty of fireplaces don't need power, but I've never seen a forced air furnace without power, and I don't think it's possible.
frosted-flakes 6y ago
Gas fireplaces generally do not require electricity and many have no fans. Exhaust is passive, and thermostats use a thermopile that generates a small current from the heat of the pilot light. The pilot light is started manually with a piezoelectric starter, or a lighter. Gas fireplaces are slightly less efficient than high-efficiency furnaces because some heat goes out the exhaust.

rootusrootus 6y ago

> Yes, they do need need electricity. Some do, some don't. Mine has a pilot light and a thermocouple. I used it to keep warm while our power was out for three days this past weekend.

throw0101a 6y ago
What's the make/model? Presumably not forced air?
- rootusrootus 6y ago
  Not sure about make & model, I'd have to find the paperwork from when the house was built 8 years ago. It's radiant, not forced air. That's an option I could add but it would require electricity for that part.
- frosted-flakes 6y ago
  The house I live in has two gas fireplaces, both 20-30 years old. They work in the same manner described above, with no requirement for electricity. Each one also has a blower that is simply plugged into the wall (one runs continuously, the other is thermostatically controlled; both are very loud). The blowers are optional, and the house gets adequately heated even when they are off.
mark-r 6y ago
I wouldn't be surprised if pilot lights aren't illegal now. They're terribly inefficient, more so if your furnace rarely lights.
- rootusrootus 6y ago
  I think pilot lights are still pretty much standard on certain appliances, like water heaters and fireplaces. Probably deliberately so they can run without power. All my other gas appliances are electronic ignition, e.g. we have to use a lighter to start the range when the power is out.
- frosted-flakes 6y ago
  In the case of gas fireplaces, all of the heat generated is used, so I would think it would be perfectly efficient. As long as you shut it off during the warm seasons, anyway.

luma 6y ago

I have two gas fireplaces, neither use power (nor have any available). Valves and safety is handled via millivolt thermopiles in the pilot light and main flame. Heating happens via convection through ducts that run from below to around/behind the fireplace itself, then out over the top. It passively moves a fair amount of air and can make the room uncomfortably warm if left on too long. I have no idea if this is common or not, but I know of at least two counterexamples to your statement here in Michigan.

ashtonkem 6y ago

GP said fireplace, you're talking about furnaces. Plenty of fireplaces don't need power, but I've never seen a forced air furnace without power, and I don't think it's possible.

frosted-flakes 6y ago

Gas fireplaces generally do not require electricity and many have no fans. Exhaust is passive, and thermostats use a thermopile that generates a small current from the heat of the pilot light. The pilot light is started manually with a piezoelectric starter, or a lighter. Gas fireplaces are slightly less efficient than high-efficiency furnaces because some heat goes out the exhaust.