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Comment by londons_explore | Hacker News Reader

For 'enthusiasts', a dual heat source system is a good plan.

But regular folk want to just pay the energy bill and have a warm home, whatever the weather outside.

They don't care to worry about lighting the wood stove on super cold days. They don't want to have to have a wood delivery separate from their energy bill, and be carting it around in boxes. They don't want to huddle into the room with the wood stove because the rest of the house is too cold.

Regular folk aren't interested in heating systems, so will pay a small premium for a system that just works, whatever the weather.

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This is a dangerous mindset in NH/ME though, because redundancies are what will keep your house from freezing. Your primary heat source may “just work” until it doesn’t (when you need it most). Then you’re doing battle in Home Depot with others in the same situation to try to claim the last space heater so your pipes don’t freeze.

Yeah, there have been numerous times when having a fireplace and/or natural gas stove saved my family from freezing. When you live in a place that routinely gets cold enough to kill, you need multiple heat sources that don’t share a single point of failure.

There is no modern system that "just works" whatever the weather. We had an ice storm when I was growing up and lost power for 3 days. Wood stove worked great as a backup, not much else would have.

Dual source heatpump + Solar + battery + propane generator might be OK. The batteries would need to somehow be kept warm though.

(The solar and battery are there to stretch out the propane supply until the delivery truck gets past whatever road blockages exist, and then addresses the inevitable shortage cause by the electricity going out.)

Of course, an 80% efficient wood stove costs a small fraction as much as the above setup, and is more reliable.

> The batteries would need to somehow be kept warm though.

If I were buying such a setup, I'd just put the batteries in the basement. Plenty of space, and it stays 40-50°ish year-round here.

Not that many homes are built with basements nowadays.

Water to water heat pump with pipes being directly under building's basement might've been pretty neat solution tbh, if you're digging for basement anyway might as well put some piping there for the heat pump

(Googles) I didn't realize basements were falling out of favor. Interesting!

Too bad few backup generators have the capability of dumping their heat output into the home via coolant loops or exhaust heat capture.

Because the residential ones are mostly small enough to be air cooled.

Exhaust heat is fine in theory but HN would be screaming bloody murder if even one person died from CO as a result of a shoddy install or cracked heat exchanger so it's basically a nonstarter if you're a big juicy lawsuit target like a business. While there's nothing fundamentally different from a forced hot air furnace the novelty factor makes fending off the ambulance chasers more expensive than it's worth.

The way to do it is probably to colocate the generator with the condenser unit and use a thermostat-controlled second loop to move heat to/from the main refrigerant loop as needed. This gives some options to keep the generator from getting too cold to start as well as recover waste heat when it's up to temperature.

Heatpump also needs to be kept warm, but those pumps do that themselves.

Given the need to maintain a ~100°F temperature differential on at least 6 days so far this year (at least here in Montana), a solar-augmented generator is probably not enough.

Our heat pump has a natural gas backup, and even it was running at about a 60-70% duty cycle on those days.

All that to say: +1 on a wood stove backup.

Starting a generator below a certain temperature becomes hard too (most lubricants do a nice impression of putty when sufficiently cooled).

As an aside, if you have a large free-standing propane tank you probably don't need to worry about stretching out the supply. I've known people who use propane as their primary heat source and can go a month between deliveries. Even assuming your propane heater + heat pump is 1/3 as efficient, that should give you 10 days of heat.

Why wouldn't a gas furnace have worked?

Gas/Oil Furnaces/Boilers still need electricity to run the blower (air into the firebox) and circulator (hot air/water from the unit to the rooms) motors.

FWIW older gas water heaters that use a standing pilot flame and piezoelectric ignition can run without electricity. Combustion products are vented passively by convection. With this type, as long as you've got gas, you can have hot water. Maybe huddle by the hot water tank?

For the sake of efficiency, most newer gas water heaters need electricity for ignition as well as to power the fan that exhaust gases.

All gas furnaces will need electricity to run the fans.

The woodstove is my primary heat source, it isn't modern, and it works regardless of the weather. But it isn't difficult to image circumstances where it fails, since it almost happened to me. I had a gout attack that made it very painful to bring in firewood. If I had central heat it would have been a matter of flipping a switch on the thermostat. Instead it got so cold that I just suffered the pain, like walking on a broken foot. After that I got my central heat fixed. It's nice to have both options.

For a backup wouldn't a gas baseboard heater or room heater work? I know they are not in favor due to fire and CO issues, but for an emergency backup they worked well enough for our parents and grandparents.

I would always want a wood stove or at minimum a fireplace in sufficiently cold climates (anywhere it gets cold enough for snow to accumulate) if my heating was electric.

Easy for your power to go out, and it’s somewhere between uncomfortable and dangerous when that happens If you don’t have a backup.

Additionally, if you do a lot of outdoor stuff in a snowy climate, a wood stove is a godsend for drying off your snowy outdoor apparel and warming yourself up after being outside.

And for every day of most years in Maine, the heat pump alone "just works". Cold this cold is very rare. Usually, the heat pump only goes out when the power goes out, in which case oil and gas heat goes out, too -- no power means no blower and circulator motors. Woodstoves have always been popular (though by no means ubiquitous) up here because the power does go out, because they're cheaper than fossil fuels, and because they're cozy. Lots of people have them even with oil and gas heat. Growing up, we used wood day-to-day and oil as a backup; many more people use the easier heat day-to-day and light the fire on occasions when they want to gather 'round it.

In cold climates, heat pumps are usually supplemented with electrical resistance heating (or even gas in some cases). The switch over is automatically controlled by the thermostat. No need for a wood stove or other hassles.

And when the electricity fails, all the systems fail. Pretty sure you'd be happy to have a wood stove in that case.

When the electricity fails, you put on a jacket and get under a blanket and wait patiently for CMP to restore your power. Most of us don't have emergency powerless heating. Even with a supposedly unreliable electricity grid here in Maine, it's still pretty common to only have heating that requires electricity to operate. Even in the north, where it's very rural and way colder, wood stoves are still an interesting thing that only some people have.

It gets cold every year, you just get used to it. It's not hard.

I suppose it's the frontier spirit that makes you say "it's -30°F, you put on a jacket and get under a blanket".

I'm pretty sure civilization would end over here if Germany had temperatures where F and C come close and heating failed.

The first winter my ancestors spent in this country, half of them died from lack of food and heat. They quite literally didn't know how to function in a non-temperate climate.

The survivors were too stubborn to die so their descendants are often the same.

Do the pipes in your house not freeze at 30 below with no heat?

It takes time for your place to cool down enough for that to be an issue, and proper pipe insulation is also a normal thing here.

A car (ICE/HEV/PHEV/BEV/FCEV) could be a backup heater

> Regular folk aren't interested in heating systems

It's Maine. Regular folk are interested in heating systems.

I grew up in Maine and have memories of losing power for 10 days in a row. Supplementing with wood is already fairly normal just to save money. Even people who don't regularly burn wood or coal still keep a stove on hand for emergencies. When the power would go out we used to have a fire tending rotation to keep the temps high enough to stop the pipes from freezing. Heating your home is definitely of interest to just about every Mainer.

Well, even if you assume 100% reliable supply of whatever kind of energy (gas, power etc.) your system needs, the heating device can still fail.

Having some kind of backup in places where it can get really cold is always a good thing IMO even if it is just for one or two rooms

> Regular folk aren't interested in heating systems, so will pay a small premium for a system that just works, whatever the weather.

So, heat pump with resistive electric assist? Of course, that's no good to you if the power goes, but then nor are most heating systems.

If your heat distribution is hydronic, I don't see any reason why you couldn't have an automatic fail-over from a heat pump to a wood stove. It's harder with forced air, but forced air sucks anyway.

I don’t know what you mean by “enthusiasts”. Dual source heat pumps are completely standard at this point. Even here in California (annual lows in the high 20F’s), it is hard to find a single source heatpump.

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