Top
Best
New

Posted by PaulHoule 1 day ago

Pretty soon, heat pumps will be able to store and distribute heat as needed(www.sintef.no)
98 points | 84 comments
chankstein38 1 hour ago|
They should've used lasagna. You could be in a tundra heating it over a fire and, as long as you get it sufficiently and consistently hot, it'll still burn your mouth 20minutes later.
cromka 46 minutes ago||
I was recently wondering if any particular type of food contributes to mouth cancer prevalence and I concluded that at the top of that list would be be lasagna and cherry tomato on a pizza/in a soup.
ortusdux 10 minutes ago||
I was interested to learn about cold district heating recently, which is basically a municipal scale geothermal system.

https://en.wikipedia.org/wiki/Cold_district_heating

jandrese 1 hour ago||
I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climates they make your house work that much harder to keep the space warm.

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.

gwbas1c 10 minutes ago||
You're about 20 years behind.

My heat pump is working great at 0F. It's 7 years old.

baggachipz 5 minutes ago||
heat pump for house !== heat pump for hot water
matwood 1 hour ago|||
I think a heat pump only for water isn't the right way to go. In the EU, new systems I see use a single heat pump for all heating and cooling in the house including heating water.

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.

luckystarr 22 minutes ago|||
While they are not as efficient or flexible, they are many times more efficient than resistive electric water heaters. I've installed one with in house air intake (due to construction reasons) in my house and it cooled down the basement by a few degrees (and removed air moisture as an added bonus). In summer the thermal capacity of the ground heats up the basement again, in winter it's a bit cooler, but it still works efficiently.
spockz 52 minutes ago||||
Which models are you looking at? I was still quoted separate pumps for floor heating and a boiler with the pump built in taking the energy from the air two years ago.

Is it something from nefit by any chance?

toomuchtodo 35 minutes ago||
This is promising.

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.”

thunfischbrot 48 minutes ago|||
Afaik heat-pumps in the EU can provide unlimited hot water–what am I missing?
Y-bar 29 minutes ago||
Geothermal (and airbased) pumps theoretically do not have unlimited heating capacity. For example my pump (Daikin Altherma Geo 3) has a 180 litre water tank so it can ”only” supply 180 litres hot water at 65 degrees Celsius and takes about a minute to heat two additional lites.

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!

ortusdux 15 minutes ago|||
I'm in the northern US and am very happy with mine. I self-installed with a county rebate, so the total cost was a Saturday and $700. My old electric unit was EPA rated for $450/year, and the new one has averaged $170/year over 4 years, so I've already broken even.
Tor3 1 hour ago|||
I had a heat pump installed in 2010. In a cold climate. Only used for heating. It paid for itself extremely quickly - less than three years. It's still going strong, in 2026. It's important to maintain it regularly, i.e. deep cleaning every two years or so. The first time I got a company to do it for me, and the technician taught me how to do it all by myself, so that's what I do. In any case having a professional doing it wasn't expensive either. And I clean the dust filters (very easy) every second week or so.
snuxoll 7 minutes ago|||
Installed mini-splits to replace the propane stove that heated my house, DIY job, so all it cost was the units themselves and some materials.

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.

stuaxo 41 minutes ago|||
What did you heat with before?
stuaxo 43 minutes ago||
They use them a lot in Norway, it's hardly warm there.
Neywiny 21 hours ago||
This is similar to nighthawkinlight's videos on phase change materials. It was very cool to see how his Ziploc bags of homemade goo helped regulate temperature.
schiffern 15 hours ago|
In this work the authors use a ceramic-coated extruded aluminum heat spreader to improve thermal conductivity through the bulk PCM, but I wonder if the graphite flake+powder additive demonstrated recently by Tech Ingredients[1] would be a viable alternative? It might need a stabilizer (thickener) to prevent the ingredients from separating.

[1] https://www.youtube.com/watch?v=s-41UF02vrU

chickenbig 14 hours ago||
Perhaps I am missing something; this product already exists as the Sunamp Thermino.

https://sunamp.com/en-gb/hot-water-solutions-thermino-range/

ZeroGravitas 13 hours ago|
It also exists, as described in the headline, as a tank of heated water.

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.

Nition 1 hour ago|||
It's funny how useful water is for power generation.

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.

DrScientist 11 hours ago||||
Indeed.

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.

Xylakant 1 hour ago|||
it also reduces peak load - you can heat water up slower with a lower powered heater. I have a 35 liter warm water tank in my garden shed that pulls about 3.5kw - an equivalent on demand heater would need 14kw or more.
a_better_world 1 hour ago|||
My hot water tank once fell off the wall. On Christmas day. Expensive repair.

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.

vee-kay 6 hours ago|||
You are right in your analogy.

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...

hedora 21 hours ago||
I wonder if this can store any heat or just heat pump heat. If it can store any heat, it would help a lot to further reduce heating costs in our modern energy efficient house.

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.)

direwolf20 10 hours ago|
Heat pump heat is just heat.
syntaxing 21 hours ago||
With the adoption of sodium batteries, I wouldn’t be surprised if solar panel + sodium battery would outperform this system by a lot.
belviewreview 20 hours ago||
A heat pump gets more heat from a given amount of electricity than if the electricity is use for resistive heating. So the ideal design is solar cell + sodium battery + heat pump.
coffeebeqn 11 hours ago||
There’s also solar thermal panels that heat up a liquid circulating in the system and cut out the need for a battery - and can just store the heated liquid.
mrguyorama 1 hour ago||
Efficiencies and effects are at the point where taking a photon, converting it into an electron, and using that electron to pump heat is more efficient than turning that photon perfectly into kinetic energy.

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.

Xylakant 1 hour ago||
Thermal solar panels have the advantage of being very simple and surprisingly effective. But if you're lacking space to put up both solar cells and thermal, you can use combined panels which have a solar cell with a backing thermal system. The interesting thing is that these combined panels outperform solar cells even when it comes to electricity generated because solar panels loose efficiency as they heat up, so cooling them actually improves efficieny. Combined panels are much more expensive, though.
danielovichdk 1 hour ago||
Stones has the ability to store heat and keep cool.

What's all this fuzz about ?

Etheryte 26 minutes ago|
It's all about efficiency. You can store heat in anything, but the question is for how long and how much energy can you get back out later. The first part is easy and how we got ovens and stoves, the second part can be pretty tricky depending on your requirements. Large scale energy storage sometimes uses massive amounts of sand for example, but they heat it to hundreds of degrees which is not really feasible in most settings.
hnburnsy 20 hours ago||
Related, TIL the US is effectively banning residential electric resistance water heaters in 2029, with heat pump water heaters being the only type that can meet the new standards. Users will see a 2-3x in cost difference and a 3 to 8 year payback on savings.
amazingman 16 hours ago||
This is exactly the kind of thing government is for, even though it's missing the other half: subsidies. At the very least buying heat pumps for the next 5 years should be tax deductible. Even better: a $2000 or similar rebate.
lm28469 10 hours ago|||
> even though it's missing the other half: subsidies

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.

DangitBobby 16 hours ago||||
That's probably exactly what will happen.

    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://www.irs.gov/credits-deductions/energy-efficient-home...
hnburnsy 16 hours ago||
These are credits that only work if you have owe federal taxes and they cannot be carried forward. I've seen estimates that 40-45% of taxpayers owe 0 or close to 0.
DangitBobby 7 hours ago|||
You can also get considerable rebates if your state participates in the "Inflation Reduction Act Home Energy Rebate Program", especially if you are low income. My state is still working on rolling it out but hopefully many people who can't use tax credits will be able to take advantage.

https://www.tn.gov/environment/program-areas/energy/state-en...

mrd999 11 hours ago|||
Eh? If you have income you owe taxes, Uncle Sam just takes it before you even see it
JoblessWonder 28 seconds ago|||
I think something like 25% of the population reports 0 household income.

(I don't understand the implications, it was just surprising when I heard that.)

direwolf20 10 hours ago|||
Federal taxes specifically.
rayiner 8 hours ago|||
The subsidies and rebates are a scam. The installers just jack up the prices until they capture the entire value of the rebate.
amazingman 4 hours ago||
This assumes the consumer doesn't know and can't look up the price of the hardware.
rayiner 4 hours ago||
The cost of installation vastly exceeds the cost of the hardware. And the installers will only warranty hardware you buy from them.
AlexandrB 18 minutes ago|||
The problem with heat pumps replacing electric heaters (in cold climates) is that the waste cold air gets dumped into the house and needs to be heated again. Generally, electric water heaters are expensive to run compared to gas ones, so people use them in places a gas heater is not possible to install (e.g. no way to vent the exhaust). This also means that the heat pump would have nowhere to vent cold air.

This kind of thing is why I don't like bans like this. The specifics matter a lot.

pkulak 19 hours ago|||
If you're making plans 3 years out in the US, you're a fool.
reorder9695 12 hours ago|||
I don't know about all heat pump systems, but mine at least requires the water tank to have a resistive immersion too. If the tank temperature gets below some threshold the heat pump refuses to work and turns the immersion on instead until it's warmed up enough.
Sabinus 16 hours ago|||
That's a Biden-Harris administration action. What are the chances that Trump deletes it as a 'Democrat/WEF climate hoax con job' as soon as he's made aware of it?
cucumber3732842 19 hours ago||
Is that 2-3x before or after the plumber marks it up?

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.

hnburnsy 16 hours ago|||
Heat pump water heater (hybrid/HPWH, e.g., 50–65 gallon equivalent): Unit prices range from ~$1,500–$3,000+ (most common models $2,000–$2,500), with total installed costs $2,500–$5,000 (higher if electrical upgrades or space mods needed). Average retrofit/install often lands around $3,000–$4,000.
lm28469 10 hours ago|||
And for small households they virtually never pay for themselves before they die or need expensive maintenance... It only makes sense if you use a lot of water or if your electricity is very expensive. In my case it's even worse, with solar panels and self sufficiency they literally cannot break even
sgc 14 hours ago|||
Electrical upgrades are almost always required, and price is more like 7k-9k around here. It's going to be seriously painful for a lot of people.
drhike 1 minute ago|||
Ehh 120v models exist. My 65 gal runs fine on a standard 20a breaker.
dashundchen 14 hours ago||||
If you were in the market for an resistive electric heat pump, you likely had the service for it already. A heat pump version will almost always require less power.
sgc 4 hours ago||
My bad, read too quickly. I was thinking of the forced change over from gas water heaters, which is already happening in the California Bay Area and will only expand.
quickthrowman 8 hours ago|||
If you currently have an electric resistive water heater, a heat pump water heater with the same heating capacity will use 3-4x less power, which means you can use a much smaller circuit.

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.

beAbU 8 hours ago||||
Heat pumps are effectively more than 100% efficient fyi. You put 1000W of electricity in, you get 2500W of heat going into the water. (Numbers are only illustrative)

Running cost of heat pumps for heating is much much lower than resistive heating.

direwolf20 10 hours ago||||
Is the heat pump heater taking heat from inside or outside the house?
lm28469 10 hours ago||
Depends on the model, but a lot use the air from their own room, that's why they can't be installed in small rooms. Models pulling the heat from outside are more expensive and require more labor obviously, and they don't make a lot of sense for places that are bellow 0c multiple month a year as the COP will drop to 1.x and you will most likely need extra electricity for the anti frost cycles
AlexandrB 13 minutes ago||
But dumping the waste cold air into the house when it's below 0C outside doesn't make much sense either.
aaaalone 12 hours ago|||
[dead]
Havoc 21 hours ago|
Starting to get more optimistic about our energy future. Things seem to be tracking pretty good
More comments...