Heat pumps are defying Maine’s winters and oil industry pushback | Hacker News Reader

Heat pumps are defying Maine’s winters and oil industry pushback

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99 pointsanyonecancode174 comments

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...

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

> 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.

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.

>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.

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.

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).

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...

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

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.

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!

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.

> ...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.

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.

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.

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

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

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

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.

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.

And far warmer

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.

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.

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.

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.

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.

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.

> 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!

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

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.

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.

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.

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

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.

> 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.

I live outside of Boston, about two hours south of Portland Maine. We have a LG Heat Pump installed in 2021, consisting of the following:

LG/LG LMU360HHV Outdoor Unit

2 LG LSN180HSV5 Indoor Units

2 LG LMN079HVT Indoor Units

We also have a natural gas furnace, now rarely used ... except when it gets really cold. During the deep freeze I wanted to see how low the LG could go before the gas furnace kicked in.

The house is 100+ years old, with updated insulation in the basement and roof as of 2021 (required to get a no-interest loan on the heat pump in our state).

On Friday, as the temp dropped, we set the units to 70 degrees F (21C). At 1 pm it was 15F outside (-10C) and the interior temp was 62F (17C). It was able to maintain that interior temp until 9:30 pm when the thermometer dropped to -3F (-20C) at which point the interior edged down to 60F and the furnace kicked in.

The heat pump continued to work all night, albeit blowing lukewarm air. At 6 am it was still dark and the outside temp had dropped to -11F (-24C) and the heat pump was still working but the gas furnace was doing most of the work to keep the interior at 60F.

On a local FB group, people shared their heat pump stories. A few only had heat pumps with no backup and reported the interior temp dropped to the 40s or low 50s (~10C). One person said that one of their two outside units froze during the night (I believe the result of condensation forming). Regardless of the type of heat, many people all over the city had burst pipes in their walls, ceilings, and basements, including several hospitals.

We are in southern NH and have a single LG LMU480HHV for our house. Our house was built in 1973 and is ~1600 sq ft. The heat pump kept the house right at 64-65F when set to 66F through the night even when we hit -15F. Now I have backup heat strips but due to some config issue they are not currently working so that was all heat pump.

> Regardless of the type of heat, many people all over the city had burst pipes in their walls, ceilings, and basements, including several hospitals.

It's amazing how many people simply don't take basic precautionary measures when extreme cold is on the way. Something as basic as letting the faucets drip will prevent freezing. Shutting off the water and opening the taps works too if you don't want to "waste water".

> A few only had heat pumps with no backup and reported the interior temp dropped to the 40s or low 50s (~10C).

A good case for not using heat pumps if you live in a place that can have extreme cold snaps. I have a heatpump for 2 bedrooms but if it stopped working then opening the doors and letting the warm air from the furnaces in would be enough I think. I'd be skeptical of having only a heatpump.

The other problem with only having a heat pump is if the electricity goes out, which happened across the region (there was a windstorm at the same time as the arctic freeze which brought down trees onto power lines). We have one friend who lost power but thankfully had a working fireplace with fuel, otherwise they would have been in a world of hurt.

The people who had burst pipes mostly seemed to be transplants from outside the northeast, including some from other countries, who have never been exposed to a situation like this or the basic precautions to prevent burst pipes. It's a hard lesson to learn, for sure.

I find all this fear mongering about heatpumps in the US currently to be a little odd, because they've been popular in some cold countries in Europe for some time. If there was going to be a problem, there would already have been a problem.

The companies making money from older heating methods are doing the fear mongering. That's not particularly odd.

Apparently part of the problem in the US is unreliable electricity supply. In Europe you can reasonably count on the electricity supply not having an outage of more than a few hours (and even that's rare). According the HN comments on past submissions on this topic, it seems that's not the case in the US.

The US doesn't have an unreliable electricity supply. The overwhelming majority of electric outages have a duration fewer than 4 hours, and most of those have a duration fewer than 2 hours.

There are problems in our more rural areas where the population density is low and damaged equipment may only affect very few customers. They're the lowest on the priority to get restored. In extreme cases it may be several days before your power will be restored. That's an outage event you can expect to occur once every decade.

But if you live in an urban area, urban being 5,000 or more people living in a town, then you have very reliable electricity.

Pushes on the part of utilities for heat pumps in the past were made with systems that honestly sucked. People remember how much they sucked.

Does Europe have cold countries? According to some quick Googling, the average winter temperature in Norway is still warmer than in Iowa (a not-particularly-cold state).

(FWIW I think heat pumps are interesting, I drive an electric car, etc--I'm not speaking from some reflexively anti-electrification ideological position)

Northern Scandinavia gets pretty cold. Various parts of Europe also have exceptional extremely cold weather; the average isn't _really_ what you want to think about when it comes to heating systems (well, it matters, in that it's relevant to the cost structure, but you really want your system to be able to deal with the reasonable edge-case weather).

Yeah, it's a crude metric for sure, but we have to make sure we're making a good comparison before claiming "If there was going to be a problem, there would already have been a problem." Notably, some Googling indicates that heat pumps aren't effective below -13F which can be the high temperature in Iowa (never mind colder states) for week on end. Are heat pumps common in parts of Scandinavia that get this cold (or colder)?

From what I can see Des Moines[1] and Oslo[2] are fairly comparable, and here in Oslo it's quite common to have air to air heat pumps.

Mind you, Oslo is quite south in Norway, it's much colder further north.

[1]: https://www.weather.gov/wrh/climate?wfo=dmx (annual)

[2]: https://seklima.met.no/months/max(air_temperature P1M),mean(air_temperature P1M),min(air_temperature P1M)/recurring_period/SN18700/nb/2003-01-01T00:00:00+01:00;2023-01-31T23:59:59+01:00

Oslo seems to have mean winter temps about ~10 degrees warmer (~23 degrees in DSM on average vs ~32 degrees in Oslo). It's a little hard to compare those tools (at least I didn't find a good way to get precise mean data on the Oslo side). And I suspect that Norway is one of the coldest countries in Europe while Iowa is not a particularly code state in the US.

I know heat pumps are all the rage on HN these days, but I looked into them for myself in Indiana, and they don't seem to make financial sense at all, unfortunately.

My utility, NIPSCO, charges $0.25699/therm for gas. There are 29.3 kWh of energy in 1 therm of gas, and my furnace is 95% efficient, so this works out to an electric equivalent of $0.009/kWh. That's more than an order of magnitude cheaper than the electric equivalent! Even a really efficient heat pump isn't going to be able to overcome that.

Am I doing the calculations wrong, or are my utility rates way out of whack, or are heat pumps just generally more expensive for everyone to run, but they still think it's worth it? I'm trying to understand how my situation is so different, because I was pretty excited about swapping out my gas furnace for a heat pump and went down that rabbit hole quite a ways before realizing my specific utility rates don't seem to make sense for it.

You have very, very cheap gas. Suspiciously cheap. Are you sure you're factoring everything in? NIPSCO's rate pages show much higher rates: https://www.nipsco.com/bills-and-payments/billing-programs/c...

In Michigan here, it's like $1/therm (doing the conversion from the Mcf they actually bill in).

Multiply your gas numbers by four, divide your electric numbers by three (to reflect a COP of 3 -- that is 300% efficiency -- for a typical heat pump), and your order of magnitude goes away.

If your gas really is that cheap, then yeah, you're still much cheaper with gas, but also you've got a sweetheart deal on gas.

Crying in NYC paying $1.85/therm, i.e. $0.063/kWh, for natural gas, and $0.231 / kWh for electricity.

Bingo! I'm so glad I asked. Yep, I was looking at only part of the rate schedule. Looks like my effective rate is actually closer to $0.96/therm, or $0.033/kWh equivalent. At an electric rate of $0.14/kWh, now we're closer to comparable.

> My utility, NIPSCO, charges $0.25699/therm for gas

Well, there you go. Natural gas in Maine is $1.95 to $3.58 per therm. https://www.maine.gov/energy/heating-fuel-prices

The thing with heat pumps is that they don't create heat, they pump it. So they are "more than 100% efficient" (meaning: they move more heat than what the equivalent energy is).

Your natural gas price (if correct) is much lower than the national average, and even much lower than your regional average. Average natural gas prices in the US for Dec 22 were $1.67/therm while average electric prices were $.17/kWh. Here's a great chart, with regional values also: https://www.bls.gov/regions/midwest/data/averageenergyprices....

I think you are right though that much of the "hype" is based on avoidance of fossil fuels rather than straight economic advantage. The hope is that eventually the electric grid might be all renewable energy, while the efficiency of burning gas doesn't have much room to go up.

As far as economic advantage goes, keep in mind that carbon emission famously is an unpriced externality. Everyone's given up on trying to put carbon pricing into place to make the economics "naturally" work out, but in a world where heat pumps and methane gas have similar to-the-consumer pricing, the true cost of heat pumps is lower.

I don't understand how you can compare the price of gas (which you convert into an equivalent $/kWh price, no issues so far), with the price of electricity, without trying to account for how long or how often either heating system has to run for... it's almost certainly not the same amount of time.

For example, let's imagine an experiment where 2 heating systems are tasked with doing the same thing -- let's say, to keep a 2000 sq ft home at an even 70F degrees, when the outside air temperature is 0F while the ground temp is whatever-it-is:

- How much gas would the gas system consume, over how many hours, to maintain that 70F temp? Maybe it uses X1 amount of gas, over Y1 hours, for Z1 price of gas, so you can multiply that out.

- How much electricity would a heat pump consume, over how many hours? Maybe it uses X2 amount of electricity, over Y2 hours, for Z2 price.

You're only comparing Z1 and Z2, how could that possibly tell you the whole story? Heat pumps can be >100% efficient (I've seen claims of up to 300% efficiency in ideal conditions), while gas maxes out at about 95%, so I don't know why you wouldn't try to measure/estimate the X and Y variables too, and why you'd only focus on the Z.

Energy is energy. Regardless of what the source is, or how long the source runs, etc etc the amount of energy needed to heat the home is constant. So what matters when comparing options is the cost of a unit of heat energy ($/kwh).

OP showed the cost of heat energy from gas to be $0.009/kWh . No heat pump can produce a kwh of heat for less than $0.009. Even a magical heatpump that is 400% efficient will need electricity costs to be 3.5 cents or less per kwh to be cheaper to run.

Heat pumps don't just convert electricity into heat. They work like an air conditioner in reverse, concentrating heat from outside into your house. Compared to a traditional heating element they're over 100% efficient.

Relative gas/electric pricing may be a lot different where you are. In the Seattle area gas is around $1.20 per therm which works out to about 24 kWh of heat per dollar. Electricity is around $0.11 per kWh or 27 kWh heat per dollar assuming 300% efficiency for the heat pump, so slightly better here. Of course if you want air conditioning that comes for free as part of the heat pump, and if you add solar that offsets the operating cost. Probably someone somewhere as built a calculator that shows where on the map the tradeoff goes one way or another.

My dad is a retired heat and power engineer up in Maine (20something years at a paper mill). We probably spent half of Christmas talking about his new minisplit. He has been tracking his electricity bill and heating oil bills in spreadsheets for years. He still has the old oil boiler in place for emergencies, but as far as I know he hasn't had to use it yet this year. He said he wanted more data before he made a definitive statement about the savings, but initial results seemed pretty promising even in the cold spells we've had

This is my system. Heat pumps are just finicky. Tons of moving parts and things to go wrong. The backup is 100% necessary, at least for now.

To be fair, pretty much anything would save money over heating oil, including just burning money.

I know it is sarcastic but there is a website where you can calculate how much it would cost to heat with dollar bills.

https://coalpail.com/fuel-comparison-calculator-home-heating

Where on earth did they get $250 for a cord of wood? Unless you're buying them 10-13 logger's cords at a time, then cutting and splitting it yourself, a cord of oak around where I live (which is not at all far from oak trees) is in the $450-550 range.

You can maybe push it down to $300/cord if you know a guy, but then you're not getting properly seasoned stuff, you're getting stuff recently cut from a dead tree left standing for a few years.

Those prices are just generic prices that you fill out with current prices. I have no idea on the validity of any of the prices filled in by default there, but I assume it is prices that whoever made the site many years ago had in their area.

Even the coal price is super outdated. If you get a reaaaaaaly awesome deal, a ton of anthracite is at minimum $350 a ton now. Those are like 2010 prices.

Coalpail is a really handy site. They've got all the hookups on the cheap coal distributors. The guy I buy from isn't listed, you just call him and ask for an appointment to meet him at his coal shed.

Frankly the best and most entertaining, overly detailed and nerdy discussion of heat pumps is on this YouTube channel: https://youtu.be/7J52mDjZzto

heat pumps are one of the best examples for science = magic.

We need more stories like this. Installing a heat pump is a win for everyone except big oil and gas. Reasons for refilling an oil tank must be harder and harder to justify every time. Perhaps one day we can repurpose our buried gas pipelines into wire conduits.

https://web.archive.org/web/20230207123148/https://www.washi...

Electricity prices have jumped about 50% this year in Maine, so the calculations many used when installing heat pumps are way off.

https://www.pressherald.com/2022/11/16/power-supply-rates-fo...

https://archive.is/VnYRJ

I have an oil furnace as a backup, but my oil furnace pooped out and the heat pump kept working during the recent cold snap. I think it's because they ran the pipe for the forced hot water from the oil furnace right up against the wood timbers of the foundation in contact with the outside, and they froze in that spot. So I wound up just running the heat pumps.

I worry about the 'futureproofness' of heat pumps.

Specifically, heat pumps use more energy on cold days. They use a massive amount more energy on the coldest days.

Today, if you use double the electricity, it costs double the money. Thats affordable as long as it happens rarely.

But, with lots of people getting EV's and heat pumps, and the generation mix getting more wind and solar, I forsee energy companies forcing customers onto dynamic pricing plans. Ie. the price adjusts every hour of the day.

Now when it's cold, and everyone else is trying to use extra power for their EV's and heat pumps, the price will go way up. So now, instead of using double the power and paying double, you'll use double but pay 50x.

Suddenly the economics of a heat pump don't look so attractive when you realise you paid $300 on one cold night...

Dual heat sources solve this (I doubt gas will ever have dynamic hourly pricing).

Retrofit market is still huge, especially in Maine where people mostly Don’t have natural gas connections and therefore don’t have a monthly standby charge for that.

When you already have a Woodstove, pellet stove, oil heat or propane heat for the cold snaps, yeah, the economics really pushes in favour there.

Seems to me that if regulators allow that kind of dynamic pricing, then it would come with much cheaper rates at other times.

Suppose you did pay $300 on one cold night... but it also turned out that your electric bill for May and September was basically $0. Would that be the worst thing in the world? Utilities are monopolies, and regulators keep an eye on their total bottom line. A massive yearly profit would come in for scrutiny.

Rather than maintaining individual gas heaters, it's more likely that the energy companies would maintain gas-powered peaker plants. If they operate 1% of the year, then we've cut 99% of the carbon emissions, with no loss of service. Even if they somehow had to operate 10% of the year, that's a 90% drop in CO2.

No utility would want to build power plant that works 10% of the year tho, that's the problem

We've already got lots of gas power plants.

The cost of converting them to peaker plants isn't zero, but it's not anywhere near the cost of building new ones.

If they earn 50x on 5% of days, it looks make sense. A problem is that other player want to join the market so finally won't earn 50x

My heat pump shuts off when the CoP goes down to 1. I still have my electric baseboards from before so they kick in when the heat pump kicks out. Can't all heat pumps be configured to shut off like mine does?

I live near Maine and have similar weather, and typically the heat pump only goes out for 3 to 5 nights and 1 or 2 days over the winter. The extra cost of a few days of EBB use is pretty minor compared to the savings throughout the other 362 days of the year.

Many parts of our grid are more efficient when it’s cold. The brownouts in heat waves are caused in part by equipment overheating. For instance power line sags causing discharges to ground. I don’t know the ratio but I wouldn’t be surprised if you can push 10% more power through a cold grid than a hot one.

When I saw futureproofness I thought you were going to talk about repairability. Thats probably my biggest concern. My heating system is largely made out of commodity parts. Aquastats and zone control boxes form the control system, copper pipes soldered on, pex crimped on. All parts you can buy at any hardware store in the country, and all interchangeable. As long as the actual tank and fire tubes in my boilers are intact, I can keep them running as long as there is oxygen. While I know the basics of refrigeration, I don't actually know how interchangeable any of the internals are, but I kinda expect them to be less interchangeable than my old boilers.

I am with you.

I live on a small remote island. Over the past number of years there has been a boom in heat-pumps here due to government subsidies. A local company appeared and was happy to fill the demand for new units. Eventually the new installs dried up and the company disappeared.

This winter there has been a number of desperate pleas on facebook for people seeking repairs on their heat pumps and split units. Unfortunately, the nearest company who can service these units is a half day ferry away.

Once more start getting thrown out I'll have to pick a couple of trashed ones up and see how hackable they are. I wouldn't be surprised if a good amount of the parts besides the control board ended up being interchangeable just due to sourcing parts from the same suppliers. I'll feel a little more confident in them after that.

Whether electric companies have that kind of pricing isn't a pure economics question, it's a question of what regulators will alow, and I'm pretty skeptical that regulators would allow that.

But "how does the grid handle spikes in demand" is the really interesting question there, and why more transmission lines (to smooth out supply/demand geographically) and reliable sources of "firm" power are important. Energy storage at scale is potentially really important here, too (and one of the reasons why home batteries are more important to the grid in some ways than home solar).

It's not about regulators, it's that you need something rarely, but it's capital costs aren't less than something you need often, so it's going to be really expensive for the short time you need it. Even if you spread the cost out over the year, consumers are paying it one way or another. Our only plan for seasonal change in production and demand is to over-build gas turbines.

You forget that if you could earn 50x the price regularly, then there would be people willing to invest in say batteries, and those people would compete and bring the price down.

Of course, if it only happens rarely, there would not be enough money in it, but then it wouldn't be a problem for the home owners either.

Also note that while electricity is expensive to store, heat storage is actually pretty cheap. It works much better at scale with say a district heating system where you can economically do seasonal storage. But you can do it on an individual level too over shorter time spans.

Utilities are well-regulated. There may need to be some adjustments to policy but it's solvable so long as we vote for the right people (a big if, for sure). Increasing adoption of heat pumps and EVs is also going to require a ton more electricity generation which is another policy issue to solve, but again totally solvable. Most power consumption is during the day and the coldest time is night, so I'd think this is not as bad an issue as it seems. We already support a huge amount of air conditioning during summers with only occasional problems.

You can purchase a very cheap base load that's fixed price. Completely green too. No need for dynamic pricing.

http://news.hydroquebec.com/en/press-releases/1261/hydro-que...

What about sand batteries? They're cheap, safe, scalable, extremely durable, and they can take advantage of dynamic pricing (or intermittent energy sources). They are easy to connect to an existing heating system.

They're relatively new, but a few companies are making them now and there's a LOT of handy homeowners playing with that tech right now.

The obvious solution to that is having a home battery. Those are expensive now (although even now, not that expensive in comparison to what a heating system already costs), but in the future they're likely to be cheap.

$300 to keep your house warm (and pipes unfrozen) during extreme cold events doesn't seem that bad to me?

Nuclear and time shifting also would prevent this. The US is instead going all-in on renewables with gas turbines to fill in the (large) gaps, locking us into carbon-based electricity for an additional thirty years, at least.

What a fitting anti-electrification PR campaign for the 120th anniversary of Edison intentionally (allegedly, and perhaps fraudulently) electrocuting a homicidal elephant to teach us of the dangers of alternating current!

https://science.howstuffworks.com/innovation/science-questio...

Anyway kids, remember, every time your heat pump spins up, Dumbo’s mom dies. Now, drink up the fuel oil the nice man in the red suit delivered last Christmas. It’ll put hair on your chest.

More info (warning: graphic images):

https://en.m.wikipedia.org/wiki/Electrocuting_an_Elephant

Edison was advocating Direct Current, not fuel oil?

Related heatpump info for the DIY crowd: Homemade Heat Pump Manifesto (2009) [1]. Although factors such as extreme cold-weather performance will be compromised, the lower cash outlay confers considerable appeal to this approach.

> My initial goal was to make available the knowledge and possibility that anybody with a few tools and gumption could convert discarded air conditioners, and dehumidifiers into very high efficiency heat sources, or cooling sources. Through the years, we have received reports of success from many people, living in many states, and countries.

[1] https://news.ycombinator.com/item?id=32959850

What’s the cost of a kWh in Maine?

The newer houses here in Japan tend to be all-electric (water, stove, AC) and the current prices (~¥40/kWh) make a lot wish for kerosene heaters of the past decades.

(40 JPY is .304 USD today)

Most of Maine is paying .264 USD/kWh this winter.

Are these air to air systems?

Retrofitting heat pumps for air to water central heating, as is normally done in the UK, is really expensive and rarely makes economic sense for an individual household.

They are air to air. The hydronic heat pumps are not common in the US AFAIK, but I’d love to hear if anyone has found an affordable solution.

They are less common but available, I have just recently been looking at options that will do combined hydronic heat and hot water for the taps. The hardware isn't too expensive but the labor for that kind of install can be a lot (highest number I got estimated was $60k).

These seem to be mostly so-called "mini-splits" which are air to air ductless systems.

Yes

I'd somehow expect some paid pro-oil/gas/propane commenters to show up in these comments and tell us we're all wrong, no different then the industry plants going out to these people in the article!

My house has natural gas.. two setups that are both really complicated. Each unit has failed in the past during extreme weather. Fossil fuel heating units are certainly not immune to failure any more than heat pumps are.

Any engineers feel like running the heat calcs on whether it's actually more beneficial to have the heat exchanger in a small enclosed space heated by the wood stove?

Im curious if the efficiency of the heat pump would allow for minimally heating the condenser to keep within the operating range.

That space might only be heated to +10°F, but would allow for the heat pump to operate normally.

What gets me is why so many localities are pushing or requiring electrification when the grid in many areas is already overloaded. For goodness sake California has fairly regular rolling blackouts and yet many cities are banning gas hookups.

The right energy tech, IMO, is “all of them”.

California's grid falls down in the summer time during peak air conditioner use. It has spare capacity in the winter time.

Even if we had discounts at the pump to subsidize things I wish different costs like environmental costs were added to the price so people could at least see the the true price to make decisions

In terms of thermodynamic efficiency, I'd be curious about running your heat engine the other way around, by doing cogeneration on site.

The bare insulation in the roof shown in the photograph gives me the heebie-jeebies.

Heat pumps are obviously great but the enthusiasm for regulating Green technology into housing design seems to me to trade the interests of the poor for the interests of the upper middle class.

Short-term interests of the poor, that is. On the next round, when non-renewable energy will become really scarce, poor won't be able to heat their homes at all without "green technology".

Easy to say “this is what you should want” when it’s really what I want.

what do you mean by that

Perhaps ironically, oil fired generators have to fire up to supply enough electricity for these cold snaps. Low-carbon nuclear, high-carbon fracked gas, and high-carbon oil are the three largest sources of electricity in Maine during deep freezes.

https://www.themainewire.com/2023/02/amid-cold-snap-maines-e...

It's not that ironic. Electrification isn't a "welp, we're done now, yay" thing, it's one of two parallel paths that works together for decarbonization.

1. Electrify all the things 2. Clean up the electrical supply

Obviously if you only look at one of the paths in isolation, it doesn't solve problems ("it's great that everything's electric, but electricity is still high carbon"/"it's great that electricity is clean, but most energy use isn't electric"), but there's no path forward on climate that doesn't involve both.

Why electrify all the things instead of decarbonize all the things? Lots of places use zero carbon nuclear district heating to take advantage of the hot water for building heat. It can be pumped 100 km from the plant as it is at Beznau.

This makes nuclear more cost effective as well since you're using a valuable product (heat) that is otherwise wasted.

The idea of nuclear power plants in the US near residential communities is a non-starter.

Solar thermal or geothermal might be an option, but I believe heat pumps outperform those options on cost.

How is it a non-starter? Nuclear plants are low-carbon and extremely safe [1]. 100 km is a long way. There are millions of people in the USA living within 100 km of a nuclear plant. Showing people the numbers on nuclear isn't that hard.

[1] https://ourworldindata.org/safest-sources-of-energy

It will never be built for political reasons.

Offer it cheap and the market will clear.

I think the answer is simply that if you run the numbers, it's just not economical to use nuclear plants for district heating. It's probably great if you can use district heating for cooling, but generally nuclear plants are very expensive so you want to get as much high-valued electricity out of them as possible.

Of you're building the district heating anyway then a district heating reservoir, a heat pump and some solar collectors plus enough wind and solar for equivalent total gross heat output (in addition to the collectors) is still cheaper.

Moving from burning fuel oil for heating to high efficiency heat pumps powered partly by nuclear seems like a really good thing for lots of reasons.

Also they used to burn fuel oil all year round for electricity, now its just the winter demand peaks. A positive trend.

edit: I also don't understand how 7% can be more than average contribution from wind, since yearly it contributes more like a quarter?

edit: I think(?) the explanation for the discrepancy is comparing Maine to stats from the Wider New England grid. Hence 24% nuclear.

Heat pump electrical usage does not go up as the temperature drops. In fact the actual heat pump itself uses less electricity because the compressor needs to slow down in order to scavenge the outdoor heat needed to vaporize the refrigerant.

What causes a spike in electrical usage is the backup resistive heat source that kicks in when the compressor cannot satisfy the demand for heat.

Installing a heat pump that is engineered and properly sized for extreme cold will prevent this issue. My heat pump does not have a backup resistive heater and I can watch the compressor cycle in realtime on my Sense Home Energy Monitor. The pattern is quite obvious once you understand what you are looking at.

-edit- power consumption tracks the heat load in normal temp ranges, I am referring to the backup heat source turning on during extreme cold.

I am forced to reply to myself again before my parent comment gets downvoted to oblivion.

YES - Heat pump efficiency drops with external temperature.

HOWEVER - A typical heat pump will be unable to operate at full power when it approaches it's lower temperature limit. It is unable to move more heat at any efficiency. The compressor will slow down or stop completely while waiting for the liquified refrigerant to vaporize in the evaporator coils.

THEREFORE - Regardless of efficiency the compressor will be using less power because it is either not running or running slowly.

WITH THE EXCEPTION OF - certain heat pumps with auxiliary electrical heaters that cause energy use to spike at extreme low temperatures.

I know all the excitement is around air source pumps, but I'd love to see ground source get cheaper to install. It's nearly impervious to weather conditions. If you live some place that actually gets cold enough to stymie an air pump, then maybe investing in ground source is worth it.

Ground source is losing the war.

Too expensive to install, and if something goes wrong, start digging.

Air source is getting better and better all the time.

In parts of Canada, such as Alberta, where it goes to -40C, anyone buying an air source heat pump is nuts. Ground source is the only viable heat pump option, in spite of its much higher cost. I guess they'll be stuck on natural gas until the climate rises some more.

Air source + natural gas for when it’s that cold is still cheaper than ground source.

Over how many years? An air source heat pump that you only use 8 or 9 months of the year will take longer to pay for itself.

Modern heat pumps are rated to about -15F.

In Fort McMurray, a large-ish city in northern Alberta, the average low temperature in the coldest month (January) is -7F. The average low temperature is below -15F about 15 days a year on average. That means you’re really using your heat pump for a huge percent of the time.

One word: robodiggers.

Incorrect, efficiency drops as the temperature differential grows. This is a basic law of thermodynamics, since you can extract energy from a temperature difference, it must require energy to create one.

Absolutely true - efficiency drops. Electrical consumption also drops if your heat exchanger can't scavenge enough heat from the air to vaporize your refrigerant. The compressor must slow down.

Or as I pointed out - you can activate a backup heat source which causes a huge spike in electrical usage. Probably better than freezing however.

Most heat pumps don’t have a backup built in anymore, though. I have 2 (LG and Mitsubishi) and neither has a resistive backup built in.

My heat pump is 11 years old and doesn't have a resistive heater. I thought resistive heaters were a new thing. Many people in the Northern US and Canada need some kind of backup and a resistive heater in the heat pump would be a selling point for many.

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