In Chicago, we have an API where we can get pricing updates every 5 minutes. I recently set up my AC (largest power draw) to cut off when the price goes above a certain threshold.

I don't have long-term data yet, as I just implemented this about 6 weeks ago, but last month's bill was 10% lower than the previous month and the same month the previous year. I'm looking forward to seeing the results over time.

I've been trying to think of what other automations I can try out when the price gets high. I thought maybe shorter light timers for automated lights, but all of our lights are LED, so the savings isn't really worth it.

Is this what we call "net metering" here in the US? Unfortunately this region only has "buy-all-sell-all", no intraday prices, and and still not enough storage to store solar from peak at noon until evening commute: https://news.ycombinator.com/item?id=45630917

A market economist might remark that perhaps that shouldn't be surprising given the lack of intraday rates and the buy-all-sell-all policies.

> In the Netherlands (and the rest of western europe), we have hourly and quarterly energy pricing (opt-in), next to pricing plans that have one or two fixed tariffs during the day/year

So your policies create incentives for residential customers to become net producers of electricity (with resilient local storage)?

What battery did you install and how much did it cost?

We have quarter-hour pricing here in Vienna and during the sunnier half of the year electricity is cheaper during the day.

It would be interesting to calculate how long it would take to pay off.

I guess if your electricity use is (almost) free, the utility needs to bill you for the use of the grid itself separately?

Economy 7 and storage heaters. Heat up bricks overnight using cheap rate electricity so they can keep your home warm during the day while you’re out working.

In fairness it probably works ok for homes insulated to a much higher standard than most British ones.

> How long do you sit in a bath?

Another Japan resident here! It is common for a family to share a bath for the evening. (One at a time!) This works because each person showers to get clean before you get in the bath. Many also have folding bath covers, which help to avoid the water from cooling down and to keep the water clean during the showers. Still, nobody wants to be last.

> My immediate reaction to this is, “there’s a way for my house to be remotely flooded”.

A smart reaction! But most baths are also whole-room units, with a floor drain, and are intended to get wet. I myself have forgotten to stop the bath water a number of times (neither I nor my bath are so "smart") and while it is an unfortunate waste of water, there is no danger of flooding, only slight embarrassment.

> How long do you sit in a bath?

80kg of meat can hold a lot of heat. It cools quicker than you think it would. Also, Japanese families often share the bathwater within themselves(but everyone showers outside the tub first), and the water will become lukewarm at some point in that use case.

> My immediate reaction to this is, “there’s a way for my house to be remotely flooded”.

Yep, remotely operating a machinery will always have some risks. Every machinery should have someone with an emergency stop button should be monitoring it at all time, ideally. But it's a well engineered tub auto-fill in the shower room, it effectively belongs to "inherently safe" category of equipment.

> How long do you sit in a bath?

I'm an American and my answer is at least an hour, maybe more, depending on how I'm feeling. I usually listen to an audiobook. Baths are for hanging out and relaxing in.

> How long do you sit in a bath?

We love our baths here in Japan

> My immediate reaction to this is, “there’s a way for my house to be remotely flooded”.

I forgot to mention that it senses and automatically stops filling the bath at a select number of liters, even if you start a bath using the physical button when you're at home.

If I'm in the bath I'm either reading a good book, or talking with my wife (I have a tub big enough for two - takes a lot of water to fill) - either way I'm going to be in it for an hour or two. As the other poster said, if I want to get clean I'll take a quick shower. The tub is nice when my muscles get sore and tight from work.

While in the US making a bathroom a "wet room" is rare, it can be quite common in other countries.

You can totally remodel bathrooms to be "wet rooms" in the US, it is well worth it.

Kids flooding the bathroom via the tub? Not a problem. Toilet overflowing? Gross, but not a problem.

I wish I would have made all the bathrooms in my home wet rooms.

> How long do you sit in a bath?

The entire point of a bath is to relax and soak in it. Otherwise I'd just take a far more economical shower.

Barring some catastrophic overflow clogging + drain clogging or other issue, your house will be fine! Your wallet may not be.

These are truly _bath_ rooms. The shower and bath are side by side, with the intent that you wash off before hopping into the bath to soak. Thus if the tub overflowed it would just go down the shower drain.

If you have a delayed start dishwasher or washing machine, you already have that.

Most baths (in the UK at least) have overflows right so the primary risk is just wasting a lot of water?

Every bathtub I've met has an overflow drain near the top, although maybe that drain is smaller then the output of my faucet, good thing mine isn't connected to the internet :D, YMMV.

Not OP but I used to sit in a bath for a long time reading, gradually adding the hottest water to keep it at a nice temp. It's been a while tho, but I'm sure there's someone like me out there :)

Japan has no domestic source of oil or natural gas. The US has so much natural gas that it’s flared off to the atmosphere in some places. Natural gas is insanely cheap to heat with as a result and condensing boilers are extremely efficient. This created a scenario where heat pumps may be more efficient, but they might still cost more to operate. The raw cost of gas excluding pipeline and connection costs in my state is $0.57 for what is equivalent to 29.3kW of electricity. It’s very hard to beat that if you have a 98% efficient boiler, even with a COP of 4 if you’re paying $0.15/kWh, that means the equivalent amount of heat moved would cost 0.15*7=$1.05 or just under twice as expensive.

Anyone who has used a nice Japanese toilet knows the US is behind in terms of bathroom tech, but personally I'm glad that nothing my bathroom is controlled by app and that I don't have to spend my time worrying about what time of day it is when I want hot water or air conditioning. I hope my power company never decides to start with "surge pricing" so they can hike up my rates any time it's too hot or cold outside.

Don't feel bad. I also live in Japan, and in my experience most homes (mine included) still use gas boilers and kerosene heaters. Not to mention that houses are built to be as cheap as possible, so insulation is almost non-existent and you boil in summer and freeze in winter.

Yeah, mini split ACs are so superior to American-style central air. I installed them into a couple rooms and removed the central air ductwork from the attic there. Thinking about doing it with the other rooms. Less power usage, every room gets its own temperature setting, quieter.

I don't see how that is possible. Either way you need the same amount of heat added to the tub. Maybe you save a little because the return pipes are not cooling the water, but otherwise the needed heat should be the same. I personally insulated all my hot water pipes which solves that worry.

Though fresh water and letting out the old will clean the water you are soaking in, which may be valuable.

I suspect what you were told is a misunderstanding.

It’s like human sous vide

in Japan you tend to shower & wash yourself clean _before_ getting into any bath. In the west people don't do it or do it very half asset. And tbh. a lot of places have combined bath/shower so you kinda can't even do it Japanese style nicely.

That alone probably will make a huge difference in how often you have to deep clean it.

That does exist. Simple versions just have a large, deep drain with coils the cold water runs through. Fancier ones have a proper heat exchanger next to the shower (requires a pump) or in the basement. Water sanitation rules probably make it non trivial to get a design certified.

Here you go: https://www.homedepot.com/p/Hydro-Systems-Fusion-Low-Voltage...

Drain heat exchangers are really expensive, this 3” by 48” copper one costs over $1000: https://www.homedepot.com/p/Power-Pipe-3-in-x-48-in-Drain-Wa...

Many people have thought about the drain heat exchanger. However drains need to be way oversized for various reasons and so you can't get good contact with the water: it is mostly air in the drain pipes.

And this is the builder-grade model we got from the house renovation company. There are higher grade ones with fancier stuff...

Presumably you need a bath with extra plumbing? What happens when the heat exchanger gets clogged with soap and hair?

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From French, tarif, a table showing the amounts of payable fees, or a list of prices set for certain goods or services (1572), via Spanish tarifa, from Arabic ta'arifa, meaning notification, coming from 'arrifa, to let know.

Big fan of Etymology as well, mostly because my brain seemingly needs to understand the origin/history of terms to feel like I've fully grasped concepts.

I'm sure you're aware of this website, but just in case anyone else wants to delve into etymology, the site etymonline.com is free and fantastic.

https://www.etymonline.com/search?q=tariff

Spoiler: the word is originally from Arabic :)

In italian "Import tariff" is "Dazio".

Tarif/Tarife means price list of anything. Your barber, restaurant, taxi service, hospital can have one. tariff as in the meaning of custom tax is a very narrow meaning considering the usage of the word in general (but that's OK).

Import duty is "gümrük vergisi", and the general list of this is "gümrük vergisi tarifesi" in broad sense. It also has a more technical name here but both I don't remember it, and it doesn't matter in this context.

In the Japan's context we would call it "elektrik fiyat tarifesi", or "elektrik tarifesi" for short, for example.

Cheers,

Your friendly Turkish HN user.

Same in Portugal: a "tarifa" can mean a price charged for a rendered service or a tax on imported products.

Schedule is a note, it goes back to the Latin word for the strips of plant used to make papyrus sheets; so it's one of the strips and by analogy a written note small enough to fit on such a sheet.

Schedules are common in UK legislation as addenda to the main clauses/provisions. Most wouldn't fit in a papyrus strip though!

R-454B contains HFO-1234yf, which has a trifluoromethyl group. Upon release to the atmosphere this ultimately forms trifluoroacetic acid, which has an extremely long residence time in the oceans (perhaps as much as millions of years, if I understand correctly).

Europe is using lots of refrigerants like r600 (isobutane) and r290 (propane).

They work really well, with the downside they are very explosive. However stories of airconditioners blowing up are really rare - it seems the risk is probably worth it for the environment.

> So you're saying "Fluorinated gases replaced [fluorinated gasses]".

Thanks! Could've worded it better.

There's no need to worry about how much CO2 these systems can either capture or accidentally leak.

I estimate they use less CO2 than is released when burning a tenth of a gallon of gas.

Not significant carbon sequestration, and an insignificant amount to leak to the atmosphere.

How is that a de facto ban, you can't trademark the common names of plenty of substances ubiquitous in daily life. The manufacturers of refrigerants don't seem like they could completely dictate what appliance manufacturers choose to use in their products.

It seems for refrigerators there are actually specific carve outs in EPA venting regulations to allow R-290 (propane) along with a couple others.

https://www.epa.gov/snap/substitutes-household-refrigerators...

If vendors don't use it, possibly due to flammability, whether a real risk or as imagined by consumers that's a completely different situation. I can't find anything claiming it's banned or even discouraged by the government.

There are commonly sold flammable refrigerant things now in the USA, I see a bunch of small fridges using alkanes and cycloalkanes, not sure about HVAC.

Is there a safety concern for propane? What is the steel man rationale that is not shareholder value?

China figured out how to make thermal imaging sensors as well. Why would you buy a $4,000 Flir with less resolution when you can get a $400 Topdon. What's funny is now it appears Flir has cut their prices dramatically to compete.

I have Haier Arctic heat pumps that are made in China. They've been great so far. I've also worked with suppliers in Shenzhen for one-off custom electronic devices that would put western companies to shame in their communication, efficiency, turnaround time, cost, and engineering quality. The new transmission I just put in my truck was made in China too.

> But in terms of value and innovation Chinese lenses have a place

What's the innovation?

I never said that Chinese goods are crap. They seem to reside in the higher middle for HVAC. My argument is that if your business is a copy cat and the produce at scale - we cull the talent and model to build truly innovative products - since there isn't funding the innovation.

Oh I totally get their game - and its a smart one. Flood the market, own the distribution and servicing and you win the game. I feel like the GREE product is tier 2 but most people don't care. Its not comparable to the well made products - they aren't junk but they aren't quality either. PRC seems to have targeted the broad market - smart move.

Id argue that the PRC price / value engineer is only viable because of the development that the innovations in heat pumps have managed to provide. Can't have one without the other. Though once price / value owns the market - innovation dies.

This sounds interesting. What make/model?

Case in point: EV's.

Inferior quality maybe was accurate 5 years ago. Now they're taking over the global automotive market. Only thing preventing them from pulling another Japan-in-the-90s against the US auto market is americans' love of oversized trucks, tariffs, and import controls. If we had a true market economy, we'd see more BYD's than Teslas (and in most global markets that's already the case).

Yes, you can still get cheap Chineesium crap off Amazon for pennies on the competitor's dollar, but it's no longer necessarily true that Chinese = inferior.

ChatGPT feels me Q1 2026 that Chinese PV exports were up 15% on Q1 2025 (cell exports up 64%).

What happened since then?

The PV stuff was just pull forward to beat a subsidy change.

As for cars, sales of ICE were down 40℅, BEV grew 1.7℅

Yes, that dangerous effect is indexed as GWP - global warming potential.

CO2 has a GWP of 1 in this context, while other refrigerants are worse - for example, R32 has a GWP of 675 (so 675x worse if it escapes), not sure about R290 (Propane), which I believe is either about 40 or 14…

Regarding EoL: At least around here, household appliances such as fridges are brought to a recycling yard and are properly taken care of in that regard… and as for heatpumps - those are only to be installed by certified professionals, for this very reason.

That's true, old school refrigerants like R-12 are awful. The downside of modern replacement refrigerants are high operating pressure (>100 bar for R-744/CO2) or high flammability for natural refrigerants like R-290 (Propane) and R-600a (Isobutane). But these are solely engineering problems, and I'm happy to know that my R-290 heat pumps at home (Panasonic L & Wolf FHS) and A/C (Midea Xtreme Save Blue) aren't awful to the environment, once they reach EOL.

If it is outside you can just use propane as refrigerant. Low warming value and it leaking to outside doesn't matter, not gonna catch on fire.

There are indoor devices using propane but they generally come with caveat "must be installed on room at least this m3", precisely so if it leaks it doesn't get to density that allows explosion

Yeah, ammonia can also be used, it's, IIRC, more efficient to use it and a bit safer because you don't high pressure, buuut enough ammonia in the air will suffocate you.

It's lighter than air so it will go away by itself if allowed to. For a purely exterior instalation it's much better than anything else.

I always wondered why we don't see more Sterling Engine based heat pumps. IIUC they can use almost any gas including air.

Would mandating the use of CO2 as a refrigerant also somehow economically motivate efforts to capture more CO2 out of the atmosphere, in a kind of virtuous cycle? Or would there be a Cobra Effect in there somewhere? I'm not familiar with the industries that refine and bottle the stuff.

OTOH, CO2 uses much higher pressures and so I'm more willing to DIY a F-gas based one. CO2 if there is a leak can cut a limb off. F-gas is generally not that high. I wouldn't want a leak/mistake, but CO2 is less personally forgiving.

Trends for new refrigerant depends on country... some to R-454B, and some to Propane, doesn't seem like C02 is very common which is a pity because I love the idea of a non-toxic non-flammable super cheap refrigerant.

This is for the Japanese market so perhaps the cons of the C02 systems are outweighed by the safety aspects.

So, in the US, for instance, the average person leads to the emission of 16 tonnes of co2 per year. The amount of co2 in your domestic heat pump (which… doesn’t weigh multiple tonnes) is more or less immaterial, even if it does leak.

> I heard CO2 is a gas with a powerful green house effect.

Compared to other refrigerants it's a paradise:

* https://www.epa.gov/hfcs/technology-transitions-gwp-referenc...

* https://en.wikipedia.org/wiki/Global_warming_potential#Calcu...

CO2 has a surprisingly feeble greenhouse effect.

Almost anything else you could use as a refrigerant is worse.

Even water vapour is a worse greenhouse gas.

Edit: wait, have I been whooshed? Apologies if so... ;-)

well, in case of water heater it moves it from your room to the water.

Which means in winter that is extra work for your heating system to compensate for

But in climates where heating only really runs in winter it's great

For a _gas_ heater, 1 would actually be unrealistically good. Conventional gas boilers tend to be about 70% efficient. Condenser boilers can do better, up to about 90%, but in practice performance is highly dependent on temperature of returning water.

PV also (usually) lets you export generation in excess of what you're using, is ~immune to freezing, and can be pretty darned efficient if the PV is driving a heat pump.

I have this one in Canada. Works well!

But having water leave the building envelope is a bit scary on very cold days. There are heat traces and freeze valves so it should be fine, but I do worry about power outages during cold snaps

Gas is an important redundancy that will be a huge loss to give up. Not merely the 2nd source of energy, but in a totally different form with totally different pros, cons, and failure modes.

It's exceedingly useful that you can run all your gas appliances at full power at the same time without needing the ridiculous amount of copper or aluminum it takes to carry the same load in electric form, and do all that while the power is out, because the power is up on poles and the gas pipe is in the ground.

Now imagine trying to replace the redundancy by ups or generator. The amount of copper, electronics, and batteries needed to make a ups that can run your furnace or ac and your stove and hot water is just ridiculous. Most people simply won't have it. Wildly impractical luxury.

It's kind of ridiculous to require $billion chip fab infrastructure to make heat, and have your stove be this delicate piece of complex electronics and the burners are all these fixed little circles that don't heat pans evenly because it costs more money to make the fancy burners large enough to cover a whole pan.

Meanwhile a gas stove is just a couple chunks of dead metal and almost no moving parts and doesn't even need electricity let alone any electronics. That is a huge practicality and robustness win.

And heats pans more evenly because the flame does not have this weird artficially sharp 0%/100% border. Even a small simmer burner heats a large pan more evenly because although there is a hotter spot in the center, the flame still spreads out and travels along the pan and up the sides no matter what size it is. It doesn't care what size the pot or pan is, and also doesn't care what the pan is made out of. That is huge.

Electronics and heat are not natural together. It's a constant fight to try to prevent heat from killing elctronics. Every day that one of the thousands of electronic parts of an inductive range sittng above a hot oven and below a hot pan doesn't fail is a lucky day. It's not just reliable by default by just being simple.

It's not a slam dunk all-upsides trade-off.

Honestly I wish there was a good way to burn wood in an insert to heat the water that goes through my radiators, to offset an electric system. We tend to get a lot of weeks in the 20 or 30’s where a decent air to water system might do fine, but it would be amazing to burn wood for a few days when it sits at 0.

Aren't they meant for underfloor heating? Heat pump efficiency drops with delta T increase, but iron radiators need 60-80C supply.

I take your point, but what you’re describing would have to cost thousands just in putting in underfloor pipes. It will never make financial sense to do it? Or am I misinterpreting your suggestion?

It's open ended to solicit the advice of anyone who cares. But, given it didn't work, 80 gallon capacity / 2 bedrooms / 2 bathrooms