Bus sized because that amount of thermal mass is bound to take up a lot of space, but capable of being buried so that it doesn’t actually take up property space.
Sometimes, in the winter, we get too much solar forcing, so if we don’t heat all, it can be 85F in the day in the house, but 60-65 at night. (We open the windows during the day, and don’t always close them at exactly the right time at night.)
What an exceptionally moronic thing to ban, the market solves this naturally. Resistance heaters are 100% efficient whatever fraction of the year is heating days. So if that's 1/2 the year and the water heater can't last 16yr because of water quality the heat pump heater will never pay you back.
This reminds me a lot of the time some jerks in west coast desert states convinced the feds to regulate plumbing fixtures so that eastern "we take from the river and put back in the river" municipalities that have more water than they know what to do with have to suffer through low flow everything.
A 100m3 (100,000 litres or 26,500 gallons) cylindrical water tank (approx 5x5m) buried and insulated with 50cm of XPS could provide around 4000kWh of deliverable heat throughout winter. Which would be more than enough for heating and domestic hot water for my house.
In the summer you'd use solar thermal to charge it to 85c. In the winter you'd run water through underfloor heating and discharge it to 35c (so you just need a mixer valve and pump).
The structural engineering part of it isn't actually that complicated (with a garden on top, not a house). You can buy plastic water tanks of that size, it just needs to be buried and have XPS foam placed around it.
Because it's volume, it scales up well. An extra one meter in each direction would increase the volume by around 60%, but you have a lower overall heat loss, so the heat capacity would more than double.
The important part of it is the XPS foam though, without this the loses are too great and you don't retain any heat. This is why insulating your foundation and slab is so effective.
Energy property - Heat pumps and biomass stoves and boilers
Heat pumps that meet or exceed the CEE highest efficiency tier, not including any advanced tier, in effect at the beginning of the year when the property is installed, and biomass stoves and boilers with a thermal efficiency rating of at least 75% qualify for a credit up to $2,000 per year. Costs may include labor for installation.
Qualified property includes new:
Electric or natural gas heat pumps
Electric or natural gas heat pump water heaters
Biomass stoves and boilers
https://sunamp.com/en-gb/hot-water-solutions-thermino-range/
The phase change stuff has positives like taking up less physical space but it's also a much less mature tech than storing hot water.
In the UK there was a unfortunate trend of ripping out these energy storage devices and replacing hot water tanks with on demand electric hot water heating ( only heat the water you need ). And new builds often have no tanks ( as it saves space in the new tiny homes ).
Very short sighted in my view - a very simple way to store energy and everyone uses hot water directly.
It's a double edged sword. In my country everyone bought pellet stoves because of the subsidies, hundreds of companies popped up, now that the subsidies have been phased out, 90% of the companies went down, with their support and warranties of course. The 10% that managed to survive increased their prices, which is easy to do once 90% of your competitors went bust
People who thought they'd save money by having the government (their taxes really) pay the bill are waking up 5 years later with expensive maintenance, the first units are starting to fail and need to be replaced but they can't afford it without the 50%+ subsidies. Not to mention that the prices pellets goes up and down faster than your average shitcoin.
GFL buying a simple resistive-heated clothes dryer, furnace, or tanked/tankless water heater in 2030.
A 6kW 240V EWH uses 25A, it’ll need #8 wire and a 35A or 40A breaker.
An equivalent HPHW would use 1.5kW at 240V, or 6.25A. You can use #14s and a 15A breaker.
Running cost of heat pumps for heating is much much lower than resistive heating.
https://www.tn.gov/environment/program-areas/energy/state-en...
Earth's oceans and seas act as giant heat sinks.
And that means more trouble as global climate change impacts..
https://www.earth.com/news/ocean-warming-broke-records-for-4...
And being on an alluvial plain, if I filter out all the rocks larger than a pea, a good 90+% of what is dug out can immediately be trucked away.
And being on an alluvial plain, if I filter out all the rocks larger than a pea, a good 90+% of what is dug out can immediately be trucked away.
• The centigrade is capitalized when used after a number. There is also a singular glyph for the entire degree-centigrade convention: ℃.
• There are also superscript numerical characters to use with volumes, without having to use formatting: m³.
There's heat storage as discussed here.
Or you can store cold water in a reservoir as a giant battery, pumping it up high when you've got excess power, and letting it back down to generate hydroelectricity from it later.
Or you can boil water to make steam that spins a turbine and use it to convert anything that can heat water (coal, oil, nuclear...) to electricity.
Similarly, in mild weather, it is more efficient to burn hydrocarbons and turn it into electricity to run a heat pump than use that hydrocarbon for it's heat energy directly.
Pumping heat is more efficient than making it.
The most optimistic hope is that the government mandate will force enough demand that manufacturers can enjoy some economies of scale and actually try to compete on price. I don't think this will happen anytime soon.
Hot water tank was in the basement, which was not insulated. So the mass of hot water contributed very little as a heat reserve for the house.
House was in a northern clime.
I do miss my natural gas on-demand water heater from when I lived in the states though. Unlimited hot water was nice, and it took up almost zero space.
You can then use a heat pump that's optimized for the expected temperature range and you don't even need to insulate your water storage tank - you actually want the cold in winter to seep out into the surrounding soil, free energy.
In summer you have cold storage for your AC.
Is it something from nefit by any chance?
https://www.pv-magazine.com/2026/01/29/samsung-releases-new-...
> The South Korean giant [Samsung] said its new EHS All-in-One provides air heating and cooling, floor heating, and hot water from a single outdoor unit. It can supply hot water up to 65 C in below-zero weather.
> Dubbed EHS All-in-One, the system provides air heating and cooling, floor heating, and hot water from a single outdoor unit. It is initially released for the European market, with a Korean rollout expected within a year. “It delivers stable performance across diverse weather conditions. It can supply hot water up to 65 C even in below-zero weather and is designed to operate heating even in severe cold down to -25 C,” the company said in a statement. “The system also uses the R32 refrigerant, which has a substantially lower impact on global warming compared with the older R410A refrigerant.”
So if I want to quickly scald myself in a 400 litre pool at fifty degrees I can’t. But if I had a gas heater that would be possible!
This kind of thing is why I don't like bans like this. The specifics matter a lot.
Propane bill (no natural gas, town of 500) from Oct 24 to Feb 25 (installed the mini splits that month) was $1200, for just heating.
My mini-splits are on a dedicated sub panel with an Emporia Vue 3 energy monitor. $604 in electricity consumption, and that includes air conditioning over the summer months.
For what it’s worth, our winter weather averages 25-35F with the occasional few days dipping to tens, single digits, and the occasional -10 freak; but these units just BARELY have a HSPF4 rating to classify as “cold climate” models. Still going to pay for themselves in 6 years without any tax credits, and 4 or so since I still installed them when they were available.
(I don't understand the implications, it was just surprising when I heard that.)
So you want the government to pick winners and you want to do business with a monopoly? This is the opposite of what you would want.
If the product saves me money, and it's _actually_ better, I will buy it in a heartbeat. If you're involving the government it's because one of those things isn't true.
It says this is both a "heat pump" and also "storage" AND says that it will run when electricity is cheap or plentiful. Thus:
1: Where does it pump the heat from? (Or is this not really a "heat pump" and instead is using resistive heating?)
2: How long does it store heat? Is this something that will store heat on a 24-48 hour basis, or will this store heat during the spring / fall when longer days mean extra power from residential solar, and then use the heat in the winter?
3: Is the unit itself "warm" when storing heat? Or is the heat stored in a purely chemical way and needs to run through a catalyst or similar to get it back?
4: Can this be scaled up for general domestic heating?
---
Just an FYI: There are plenty of schemes with resistive electric water tanks to store heat when power is cheap.
https://www.youtube.com/watch?v=uqyAWkXXt3A
https://www.neshw.com/residential/solar-heat-pump-water-heat...
I have one of these: https://cta.ch/en/private/products/ah-i-eco-innen
I got it in October so most of the time I've had it has been <10C. It's produced 806.3 kWh of heating for hot water and 6587.2 kWh for the floor heating. It consumed 302.7 kWh and 1801.4 kWh respectively, for a COP of 2.66 and 3.66.
unrelated: a simple technical solution to your window problem would be home assistant and a few sensors to notify you when the windows are open too long or open when too cold inside.
Physics does not apply to lasagna.
Also I suck at making lasagna.
As it works on phase change (e.g. think of melting ice) heat is added (or removed) without changing the temperature of the store (which, I guess, might be hotter or colder than where the heat is extracted or used).
2. With good insulation you can easily store heat for a day which is all you need. You're never going to get close to storing summer heat for the winter. That's not impossible but not feasible for something this scale (and not cost effective at any scale).
3. You just heat it up and cool it down. There are no fancy chemical processes happening other than the phase change. It's exactly like a phase change hot/cold pack you can buy on Amazon.
4. I'm pretty sure this is designed for domestic heating...
It's kind of an obvious idea tbh. I don't think they've done anything super innovative... They made an aluminium heat sink..
Compared to nearly 100% usable energy from normal solar panels.
Furthermore if you have a heatpump you can convert this electric energy into heat energy with a factor of >3 (COP).
It's gravity that does the generation. Water is convenient because it's weight per unit of volume is very high. Higher than most things we can get our hands on and it's also exceptionally safe.
Since water isn't perfectly clean the main problem you face is corrosion. Which can take a great system and turn it into a nightmare of buried leaks and sudden problems.
As far as our options go it _is_ really convenient.
my childhood public school took us to some big commercial building- I think it was Sears' HQ- and they proudly showed us the huge blocks of ice providing chill during the day.
Personally, I prefer an air-source heat pump hot water tank. It significantly dehumidifies my basement.
I live in Switzerland where these are available. A Cowa 58 [0] costs CHF 4692 [1] and stores up to 13.5kWh. If you're heating the water with a heat pump, that's ~6kWh of electricity, so ~CHF 782/kWh.
I'm in the process of installing a 33kWh battery and the battery + inverter cost CHF 13600 in total for just the hardware, so ~CHF 482/kWh.
If you add solar panels, the inverter does double-duty producing AC from both the battery and the panels. The battery does double-duty producing both hot water and allowing you to use solar energy outside the times when the sun is shining.
That said, having ordered a heat pump recently and being in the process of having solar + batteries installed, the amount of electrical work needed for the solar/battery install is substantially higher than was needed for the heat pump and here, the labour costs quite a lot, pushing the upfront cost difference even higher.
I think that's where these heat storage things fit in: they have a much lower upfront cost. No matter how cheap the battery, for it to be useful in a Swiss residence, it needs to output a substantial amount of 3-phase power (3-phase is standard here, even in most apartments), which means you need to spend a couple thousand Francs on an inverter and electrical work. These heat storage devices are quite cheap and don't even need someone qualified to handle refrigerants, I imagine they could be installed by a normal plumber.
That reduced upfront cost makes them far more accessible than electrical batteries, at least for now.
[0]: https://www.cowa-ts.com/uploads/files/Dokumente/Datenblaette...
Versus resistance, which is exactly as efficient at 0°C and 1000°C, and why those storage heaters used to make sense.
(And storage is directly proportional to temperature differential above interior ambient)
So we already have an effective way to store heat which can work for decades without servicing and is also cheap to produce (in terms of money and energy consumption).
It does seem a little silly to have these chains of heat pumps all working in various directions. I read about "cold district heat" in a sibling comment which circulated lukewarm water to use as a heat sink or source with heat pumps. Maybe something similar could be done with a water or refrigerant loop through the house. Probably not economical to do all the plumbing though.
Come to think of it, if we had a big salt slurry that transitioned at 72F in the floors, that would probably do the right thing. It’d create a step function making it hard to heat above 72, or cool below it.
I wonder how much density changes as these things transition. Would a static pool (mixed by freezing) work, or would it need a pump?
(I also imagine using the circulation in a convection oven might help as well. Also, preheating your oven! Even if it's a toaster oven.)
Heating water is very energy intensive, fridges are a rounding error compared to water heaters
Use the power button to select a lower power level, and cook the food for longer.
We have been buying heat pump PTAC for the hotels for last 20 years, and price difference is usually 5% between with and without heat pump.
Seems like all companies are colluding with each other for marking up prices.
Does seem like a lot of added complexity (and likely machinery cost) though.
https://www.youtube.com/watch?v=7J52mDjZzto
https://www.youtube.com/watch?v=7zrx-b2sLUs
Unless you live in a cold climate, they are worth it for a discounted energy bill =3
As an aside, HP dryers are really elegant tech, and it's a shame they're not more common. They use the heat pump not just to heat the air in the dryer, but also to condense the moisture back out of it, so just the water can be drained away instead of needing to exhaust the air outside. So you need much less energy overall, and you don't need a dryer vent. The only downside is they're a bit slower, but ours has a resistive backup option for when you need clothes dry asap, so really it's just price.
I've stopped needing to sort my clothes out as a result, I used to hate putting synthetics in a regular dryer because they get worn out so fast that way.
Cooking food for 2 minutes at 50% power gives a noticeable difference in average temperature compared to cooking food for 1 minute at 100% power and waiting a minute.
And I don't always know what it decides to do as far as turning the magnetron on and off on its sensor modes, but it'll spend a while doing automated reheat and potatoes and what not and it'll be dang near perfect every time.
Don't get me wrong I'd love an inverter microwave, truly a better option. But its not like the duty cycle process has no impact.
Depending on the needs, resistive heating can get hundreds of degrees hot, but the best heat pumps that I know of can only raise the temperature about 60 or 70° f.
But, as a result, Ecombi has a much lower system efficiency than a heat pump, since it's essentially just a space heater pointed at a rock. It only makes sense for jurisdictions with time-of-day variable pricing of electricity, and trades off simplicity and low initial purchase price for lifetime cost.
This is ground basically. How deep varies but few meters underground you basically have average yearly temperature. You could pump heat from house to the ground to take it out from the ground during winter.
It's a GE Profile model FWIW. It seems like a good product line from my experiences. The matching oven has also been a good performer overall.
edit: also on heating question - Moscow's electricity is provided by 40 or so big gas-fired steam turbine generator plants, about 10GWe total. District heating serves as cooling for all this power generation.
Storing cold during the night is probably more efficient
I thought about making ice blocks with a freezer on my balcony, probably not a good idea
No one is storing 1000C water at home.
It is true that the temperature deltas affects efficiency. You can use the thermocline to draw from the cooler lower portion of the storage tank to push this further. Or less technically, just a bigger tank, though this has some tradeoffs.
In warmer countries they are set up differently can act as free air conditioning by extracting heat from indoor air at the same time as heating water.
If you have a poorly insulated house then the fix is to insulate it, which is what a lot of people are doing around here, with very hold houses. My house is less than 60 years old and very well insulated for the time, and it holds up even today - it's always warm, with the heat pump not even close to its max power.
I live in Ireland where night/day temperature swings are small. To cool my attic on a hot summer day I'd need to move that heat into a large water tank that gets used for laundry, cleaning, showers etc and is refilled from cold mains water. But fitting an air to water heat exchanger inside my attic would be a big expense and I would have to make sure I didn't freeze the attic.
Regular air to water heat pump could be hooked into my existing tank I suppose?
I actually don't know the answer. I'm just thinking that there must be more to it, if the answer was as simple as "just heat water".
I don't really understand what the aversion is to forced air climate control here other than "it's not as comfortable" which from what I've gleaned from other people is taken to mean noise/moving air/humidity. Coming from the southern US, I find all of those points to be a non-issue for me. I've slept with a fan on my entire life, so if I can shave off 50% of my heating costs for a few decibels of fan noise, sign me up!
Isn't that what we call a combi boiler in the UK (and Europe?) I've recently moved from having a big hot water cylinder to a combi. The space saving is nice, but there are downsides.
Waiting for the hot water to come through is annoying and I'm often just wasting cold water waiting for it to come through hot. There is a "pre-heat" feature which would be nice, but then it would keep it warm 24 hours a day which is ridiculous. Maybe some better boilers can time the pre-heat. That would probably be close to perfect.
The other downside is it can only really supply one tap with hot water. So if someone is having a shower and someone else runs a hot tap it can be unpleasant. Requires some coordination between householders.
All in all I would definitely prefer a cylinder if I could afford the space it takes. Modern cylinders are incredibly efficient. I once turned the heating off for a week while away on holiday and when I came back the water from the cylinder was still tepid.
With hot water tanks, they are unfortunately pretty badly insulated as well, with some of them loosing heat very quickly. Depending on how you plan on using that water, you also have to make sure the temperature never dips below ~60C to avoid legionella from spreading.
I actually think that heating your home slighly higher than you‘d usually do is the simplest and most effective approach, assuming it is properly insulated. Just rise the target temp for 1-2C when the energy is cheap and reset it once it isn‘t. Probably not as efficient, but extremely simple to implement.
Sure, heat pump hot water tanks are a thing. Air-to-water heat pumps are less efficient than air-to-air as they need to reach higher target temperatures, but it will be more efficient that straight resistive heating by a factor of 2 at low input temperatures, and 3+-ish at high summer temps.
The primary concern would be the quality of the tank’s insulation. I would hope HPHWTs are good on that but if you’re looking into that you probably want to double check the heat loss of the tank.
So the way I see it, is that this material should be able to quickly store heat with the using the low temperatures that heat pumps provide, and be able to store it with minimal losses until it is needed.
They both are rated for annual kWH usage less than the US EPA yellow label can display (for their category of tanked water heaters, i.e. competing mostly with resistive heating models).
Annually water heating is about 3% of my energy consumption.
Yeah one of my colleagues has a preheat which can be triggered manually and via automation. They also have a preheat loop which cycles hot water through the entire piping as the boiler is on an edge, so it takes ages for hot water to reach the far bathroom.
>Versus resistance, which is exactly as efficient at 0°C and 1000°C
It isn't. The difference is smaller than for a heatpump tho obviously.
No, it's about temperature difference. My heat pump water tank heats about as quickly as resistive water tanks; but it could never heat to hundreds of degrees.
Do you mean a heat pump dryer? Those aren't taking heat from the room; they work by sending the air inside the unit through a powerful dehumidifier. (I have one, it's very nice.)
At that price, resistive heating cost about as much as what I paid for gas at my old house.
I went with a heat pump to hedge the bet. (I was also pointed away from geothermal.)
If the insulation wasn't as good, or electricity more expensive, I would have used a different heat source. I was looking at pellet furnaces at the time, but never seriously got into the research before the solar proposal came in.
Now, this is of course no concern in the "my water heater is in my attic or attached garage" parts of the country such regulations come from...
I have a heat pump btw., with COP 4.5 (below ground). Costs me EUR 2.5 - 3k per year to heat the house.
That really depends on the oil heater, no? You can't compare a heater from the 70s with a modern one. That's like saying I don't drive modern cars because cars in the 70s were unsafe and stank.
Electricity (standard): 33.34 p/kWh
Heating oil (gas oil): 10.54 p/kWh
Kerosene: 6.20 p/kWh
Mains gas: 7.68 p/kWh
https://www.nottenergy.com/advice-and-tools/project-energy-c...
If you have your own solar ( either direct solar water heating, or solar electricity generation ), the hot water tank is a simple, cheap, reliable energy store.
Sure capacity isn't that great - but pretty much every house in the UK used to have one, so it adds up.
It is true that heat pumps coefficient of performance drops as the output temperature increases. So you need a proportionally larger hot water tank to store the same amount of energy. So it is fair to say there are tradeoffs. But hot water storage is still a necessary part of most heat pump installs - because peak output of heat pumps tends to be below the heat demand of showers.
Where does the energy go then?
One interesting case where "at the same time" actually does happen is overnight car charging. Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that.
Many heat pumps are installed with a large insulated buffer of water (for ex. 300L), which stores heat pretty well?
And homes that use underfloor heating in concrete can store heat pretty well too. Many people use that to heat up the home when energy is cheap and disable the heat pump when it is expensive.
This is partly due to a change in the refrigerant used.
See page 758 of the Chapter 22 for the Unicode 9.0 standard:
Is this adequately maintained even as temperatures drop? I was recently considering getting a heatpump in addition to my gas installation but I assume I need to go for more than a bit better than resistance heating during winter for that investment to make sense.
I am still convinced the lava cheese insulator is there only to burn people's insides with boiling pineapple.
Although pineapple flavoured floor heating does sound delicious.
Here in the UK some electricity providers offer 'smart' charging (e.g. Octopus Intelligent Go).
In that situation the energy provider controls when to charge the car - e.g. you say "I want the car at 80% by 7am tomorrow" and the energy provider controls the timing of charges.
That's how my EV charges - I plug it in, and Octopus control it.
Benefit for me is that whenever the car is charging my entire home's use gets the overnight rate (even if part of the schedule is charged during the day).
Benefit for Octopus is they can use my car to balance grid demand / schedule the charge when it is most financially effective for them.
I can - at any time - override that logic if I just want it to charge at a specific time for whatever reason.
(I presume this sort of arrangement is becoming more common in other countries too)
I've got a 1930s semi-detached house (UK, north of England) - heated solely by a ASHP for both heating and hot water.
Our Seasonal Coefficient of Performance is currently 3.47 (347% efficient) - even if limit that to just last month (coldest month of the winter so far in the UK) our COP was 3.25 (325% efficiency).
Roughly speaking if you can achieve a COP over 3.2x in the UK it should be roughly on a par with gas, assuming you go 'gas free' (i.e. you can make the saving on the gas standing charge).
Personally we're running at ~£200 annual saving vs. my estimate of what costs would be for equivalent gas boiler - that's thanks in part to being able to do all our hot-water heating at night rates.
House wise - we don't have cavity wall insulation, have 15+ year old double-glazing and probably should have more insulation in the loft (it fills the rafters but I think these days that's considered not enough).
Also with changes to ECO (energy company obligations) and RO (renewables obligations) the differential between gas and electric will reduce further
Anyhoo - added my example to show that ASHP can work perfectly fine in old, poorly insulated homes in (moderately) cold climates.
ECO/RO link - https://www.moneysavingexpert.com/news/2025/11/energy-bill-c...
The only problem with resistance heaters is the large current draw to heat water for bathing. Central heating can be done at lower temperatures (as is the case with heat pumps), but bathing cannot.
There are some resistance heaters with built in (electrochemical) batteries aimed at reducing peak current, but I'm assuming the ban would affect those as well...
Cheese melting takes energy Cheese freezing, releases energy.
So you do actually get the temperature to remain at the melting point of the cheese for a longer period of time if you have enough % cheese to be significant.
https://www.heatgeek.com/articles/legionella-and-water-tempe...
I've been quoted prices to insulate my house that represent 50% of the original acquisition price of the house.
I would need to pay 0€ for both electricity and heating for the next 100 years for this to make sense at current prices.
https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...
So the temperature swing is smaller (almost zero) so heat losses due to non-infinite insulation are reduced.
Without rebates, they're similarly priced.
As far as reliability, they both have decent warranties and backup heating elements. Both heat water without internet connectivity. Similar performances (as far as heat output).
Overall, I feel the AO Smith is more customer friendly. Definitely easier to install:
1) AO has both top and side water connections; Rhm has one top and then one side connection (why?!)
2) AO's venting connections are far superior to Rheem's (which require custom/expensive adapters if installed in spaces <700sqft) — AO just has two standard 8" duct connectors on top... so much easier/cheaper to install into a closet. Rhm's top slit needs a $120 plastic adapter, and then ejects to the side (of a 24"D cylinder) [again: why?].
3) Rheem will not stay in ELECTRIC-HEAT (only) mode, for longer than two days — it automatically reverts to the prior heat pump option (which is annoying; you can use the app and set up a schedule to "force" electric mode... but then you have to use an app). AO stays in whichever mode you select.
4) AO is just nicer presentation. Despite a few obviously less-expensive components and design decisions... the AO is better thought-out. Just as an example, the Rheem has a threaded 3/4" socket for condensate, while the AO has a pre-installed (cheaper, too) drip tube.
5) The AO's electric vault is on the side (and not top) so a top leak is less likely to fill the conductors // corrosion. This is a better decision.
6) Rheem will likely last longer, despite being two years older. We'll see.
Either one will save you a lot of electricity + bonus dehumidification (while operating). I bought whichever was cheapest, the first time; now I would buy the AO even if ~$250 more expensive because the install is that much easier. This last rebate period I bought three =P
For instance, masonry was a common building material and that is not easy to insulate. You need to add many inches of insulation on either the outside or the inside, both of which have complications.
Even in a basic stick framed house, you’re still talking about taking down all the exterior walls, likely involving removing plaster and replacing it with drywall. Plaster has a number of nice properties, so it’s sad to remove. And that’s not to mention the price of this work.
Finally, roofs need special consideration. Most roofs today need to be properly vented, which was not as much of a consideration when the houses naturally breathed. Venting today is often done with soffit vents. Yet on historic houses, soffits are typically one of the nicer details. It’s not trivial or cheap to install venting in such cases.
At that scale, it's definitely possible that you all plug in your electric cars and turn on your heat pumps more or less at once on a cold evening after work and start cooking your local transformer. Not my day job but I think it is a potential issue when everything is sized assuming ~2kW average demand or something
That's why they're so great for warm climates though. The water heater also cools your house, especially as that heat is then lost down the drain. Everybody in the south should be jumping on these.
Most people think they should be able to put food in, nuke it at full power for as short of a time as possible, and then immediately shove it in their face with no consequence and we all know that doesn't work yet most of us will keep doing it anyways.
The air inside the dryer is cycled through a dehumidifier and then the water is pumped out into a drain. This is in contrast to a typical US dryer that just blows hot air into the drum and then out a tube outside. Apparently most of the world doesn't do it like we do.
You're right, of course heat pump water heaters use tanks to smooth out DHW demand, but that same thing isn't feasible for space heating.
2. The electrical to heat conversion efficiency is indeed 100% regardless of the temperature of the resistor. And if you're putting out 1000W, then all input losses are also identical. If you put a 1000W light bulb in the middle of your room, or 2 of them but run both at 500W, you'll get EXACTLY the same heat output in your room, but the single bulb is much hotter.
Right, but UK has/had "storage heaters" which were bricks with nichrome wire. They would heat the bricks really hot during cheap electricity times, and use that heat the rest of the day.
EDIT: I misread "ripping out these energy storage devices" as https://en.wikipedia.org/wiki/Storage_heater
Of course heat pumps for DHW should all have a tank for smoothing demand across several hours.
From a quick skim around it appears ASHPs can continue to work at -20c even -30c IF they are units that were designed for cold climate operation, albeit they can't secure the same SCOP/efficiency as they can with warmer temps.
It also looks like homes in these colder areas will often install the ASHP + have some form of additional heating as a back-up (e.g. electric heating) to compensate for the limitations of the ASHP in the coldest weather.