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There was a thread [0] on /r/Maine in the aftermath of the extreme cold snap last weekend, when outdoor temps dropped into the negative double digits, where people chimed in on how their heat pumps held up. By and large, they confirmed that the manufacturers' claims are correct -- they do keep working (albeit less efficiently) down to the rated temperatures and in some cases even below. The winning strategy, at least up here, seems to be a cold-weather heat pump (commonly rated to -10F) for normal baseline heat and a woodstove to fill in when it gets really cold or the power goes out.

[0] https://old.reddit.com/r/Maine/comments/10t0yd9/heat_pumps_i...

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In addition to this, I think we should go back to doing things the hard way, the old-school way: adapt and adjust your lifestyle to temperature changes like our ancestors did. Let the temperature dictate your cooking: do the dishes that require oven use, that require you to have 3 stoves on at the same time (and crucially, avoid these dishes in the summer!).

Go on a bulk in the winter time so that you are more resilient to cold with that extra weight on you (and go on a cut in the summer). Set the temperature a little colder, put on a sweater, do more physical work. This is how the human body has evolved! - to be able to do withstand a little bit of cold, to sometimes be hungry for a long time. Always adjusting your environment for the absolute peak levels of comfort is probably not doing you any good and the heat pump's limitations are not that bad in this regard.

I think letting your life revolve around customs is fun as well as a biological necessity to some degree. If you skip the chance to test it out and let it face a challenge every now and then, you're not doing yourself favors. This elderly gentleman can make it fine alone in Yakutia where temperatures can reach as low as about -100 deg F, you probably can as well: https://www.youtube.com/watch?v=IOltGIaDPlY

Your ideas are good for today, however I question how accurate they are for "our ancestors." Most people in e.g. the colonial days didn't have an oven - they went to the town baker to use theirs when needed. They also didn't have three stoves and all the pots and utensils required to use them simultaneously

While three stoves was probably ahistorical for most homes, a fire which heats the home and is also used to cook (food in ceramic containers) was absolutely commonplace. In particular, a controlled cooking fire in the center of a single-room thatched-roof home was the template for much of Europe, Asia, and for some of the North American natives, albeit at different points in their history.

Of course.

Worth mentioning also (moving away from the poor now) wingback furniture, flannel pajamas with caps, canopy beds, bedwarmers with hot rocks or coals from the fire, three-piece wool suits during the day, etc...

Franklin stoves sold like hotcakes too, didn’t they? As an improvement over the hearth and the pot arm, which were themselves improvements over the three stone fire (which is still used by an alarming number of humans today).

They might not have had an oven, but they certainly had a fire of some kind.

You are not wrong.

Blankets... sleep with a sheet in the summer, and the 14 layers in the winter. I know a few people who run the AC very low at night to keep cool with enough blankets to be comfortable in an igloo.

Every thing needs to change in the winter... Those PJ pants you plod around the house in, fleece in the winter ONLY. Seasonal clothing matters too!

Body insulation is way more efficient than the pink stuff you put in your attic! Cheaper, too!

>Go on a bulk in the winter time so that you are more resilient to cold with that extra weight on you (and go on a cut in the summer).

Do not do this:

https://onlinelibrary.wiley.com/doi/full/10.1111/obr.12251

Just wear some clothes. I wear fleece-lined hoodie and sweatpants in the winter. There's also that crazy guy who recommends long underwear, but as a skier (with plenty of experience wearing it), you'll never convince me to put that stuff on inside.

I reward myself for doing stuff outside in the cold with soup, hot beverages, occasionally baked goods.

Yeah it's true. I was just joking that our air fryer doubles as a space heater.

While, sure, we can adjust ourselves, my concern is more for my house - if my heat pump can't keep things warm that means the cold bits in my house aren't getting the heat they need when they need it the most to keep my pipes from freezing. Yes, that should be solved with insulation too, but you don't really find out about those problems until after they happen.

Pure n=1 anecdata. Last winter I was on vacation and saw via Nest app that my boiler died. We have a heat pump that 99% of the time is used for AC, and sometimes for supplemental heat. We only have them in the main rooms, so things like bathrooms and such receive no benefit from them. The unit outside is a Mitsubishi Hyperheat. I logged in and turned the units on just to keep the house from freezing.

BUT during that trip a giant blizzard struck the area. I forget the air temps and they definitely weren't double digit negative but it was quite cold with high winds and a lot of snow to boot. They held the house together well enough in our absence.

Our bodies are able to compensate for extreme cold a lot better than extreme heat, so it's important to recognize that we are going to increasingly need effienct heat management systems that prioritize removing heat in an efficient and scalable way rather than focusing on adding heat. As you say, we can make up the difference ourselves usually by just adding insulating layers to retain core heat.

There’s something brilliant about having a big pot of soup stock simmering down in the dead of winter. Not only are you heating the house, you’re also humidifying it with the steam from the pot.

The tricky one is canning. Harvest dates sometimes line up with heat waves and that’s either a sit outside with the windows open situation, or a suffer for your winter survival situation.

Some things you don't have to can right away. For example, we found that we can pick strawberries in-season, wash and top them, freeze them in gallon ziplocs, and then make jam later in the fall and it comes out the same as if you jam them same-day.

> ...do the dishes that require oven use, that require you to have 3 stoves on at the same time...

This doesn't make a difference in my home in the winter. That said, I'm one of those types that has no issues putting on gloves and layers of clothing and driving around in my doorless and topless Jeep in the winter too.

Yeah this might work if you heat your oven with wood.

The outside of our oven gets merely warm. It's safe for our children to touch it.

For the stoves. The pots get hot, fast but the stove itself is more heated up by the pots than generate heat on it's own.

That heat has to go somewhere! But you are right that you may not feel the difference especially if your run the hood and it vents externally.

Your HVAC was designed for environmental comfort, the oven for cooking.

> Let the temperature dictate your cooking

Focusing on historically-seasonally-appropriate cooking also means you'll tend to get cheaper produce and it'll be higher-quality, since it'll be in-season at least somewhere in your hemisphere (even if you're not at the right latitude/growing-zone for whatever cuisine you're cribbing from). Traditional seasonal recipes won't include things that were hard or impossible to find in a given season, without modern farming, refrigeration, pasteurization, transportation, et c, in whatever region they recipes are native to, except maybe a few things that are especially canning- or pickling-friendly.

Squash dishes in the fall and early winter, a general great abundance of produce enabling colorful dishes with a large variety of veggie ingredients in the Summer, heavier on beans and meat and potatoes and starch and soups in the Winter (but still some salad greens! At least before the coldest few weeks of Winter, most places), green things galore in Spring.

The rhythm of it's nice. And it can make end-of-week use-up-the-leftover-ingredients dishes easier, since the space for those for a given area in a given season is usually well-explored and well-documented, so if you stick to one area and one season for inspiration for a week's menu, you can benefit from that.

I like these schemes where two solutions with different performance metrics are combined that cover each others weak points. Other examples are RAM and cache memory, and short term (battery) and long term/backup (hydrogen) energy storage.

Hydrogen is terrible backup storage, as it evaporates through all known materials. Even as metal hydride or ammonia it's not great. (Density for the first, stability for the latter.) This is why everyone still uses hydrocarbons. Pity they don't make or burn them cleanly.

Hydrogen for backup storage for the grid would be stored underground. This is a demonstrated working technology.

Underground in what? Leaky container or an even more leaky cave?

There is a reason why there are low levels of hydrogen even in oil fields, while there are high levels of methane...

Underground in geological formations. For example, in cavities solution-mined out of salt.

This is a known and proven technology. Despite your pearl clutching, the hydrogen doesn't escape at a rate that would make it unworkable.

Here in NH it took a while to get warm but it worked. And it was cold enough the generator didn’t start. Which obviously made having a second source of heat in the interim important.

Don't they just start working essentially as effective resistive heater below some temperature ? So theoretically just oversizing it a bit should've been enough for the once in 10 years cold snap event.

Woodstove with some supplies probably cheaper than oversizing tho

I've heard that with heat pumps you want to be very careful about getting the sizing correct. So if your plan is to get a heat pump and improve home insulation you need to do the insulation part first so you don't end up with an oversized heat pump.

This is, basically, my plan out here in the midwest. I want a wood burning stove insert into my fireplace, improved insulation, and finally a heat pump. Long term I'll completely eliminate natural gas.

And far warmer

No, at some point they’re worse than resistive.

I've heard some heat pumps have a resistive heater in them which is used if the heat pump's CoP goes below 1.

So many people will say that but even at -13F the LG Red heat pump I have is rated for a COP of ~2. Which means it is still twice as efficient as a resistive space heater. Now capacity does fall off and that can cause issues since heating demands rise as temperature drops but that is an initial design constraint that just has to be designed around.

NEEP has a great website to find all kind of specifications for heat pumps. Below is the link to the unit we have at our house in Southern New Hampshire. https://ashp.neep.org/#!/product/53914/7/25000///0

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.

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 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.

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

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.

> 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.

> Regular folk aren't interested in heating systems

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

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.

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

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 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.

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