It does match physics if you consider other factors. Apart from the heat pump scenario, this statement can also be true when you have condensing boilers (and okay-ish insulation)
The reasoning: when you heat up the house, then your boiler needs to produce constant high-temperature water. When you keep the house at the same temperature, then the boiler produces much lower temp water and it is more efficient.
Insulation also matters because if your house has outer insulation then it means that heat transfer from the house to the environment is mostly blocked, but cross-room heat transfer is likely not (through the walls). Therefore it is better to heat the whole house than heating just a couple of rooms because if you do the latter then you'll end up heating the whole house anyway but you're using less surface area (meaning you need higher flow temperatures, meaning less efficiency).
> The reasoning: when you heat up the house, then your boiler needs to produce constant high-temperature water. When you keep the house at the same temperature, then the boiler produces much lower temp water and it is more efficient.
How does your boiler produce heat for your water in your scenario?
> Therefore it is better to heat the whole house than heating just a couple of rooms because if you do the latter then you'll end up heating the whole house anyway but you're using less surface area (meaning you need higher flow temperatures, meaning less efficiency).
Just model the other rooms as very weird wall to the outside.
We've moved to an new apartment (house) and we had to do a full renovation. It doesn't have modern insulation and I calculated that for the time being the ROI on insulation isn't worth it. It's a multi-floor semi-detached house and I wanted the best comfort and the most economical heating possible.
In particular: stable and individually adjustable temperatures for bedrooms and living rooms; underfloor heating in some rooms (bedrooms), radiator-based heating in some others (living room), and combined UFH+radiators in some others (where UFH might not be enough during extreme colds).
I thought I can just pay someone some money and they'll set up the controls for me. It must be a simple exercise, right?
I could not have been more wrong. After spending a few hours of understanding the setups that "experts" have recommended, I figured out edge cases where they would be either wasteful or uncomfortable (meaning: unnecessary and inavoidable temperature overshoots or undershoots, etc.). I had many-many rounds with Honeywell, Tado, Siemens, etc. and every single one of them had _major_ issues.
The renovation got a bit stuck because of this, but the plumbing was ready so I wanted to see whether the pluming and pumps are working, at least. So I connected the pumps and valves to "smart plugs", i.e. Zigbee-controlled plugs, so that I can see that they turn on. They did, which got me thinking...
Right now I have $20 Zigbee temp sensors sprinkled across the house, $30 smart plugs and relays driving valves, pumps and the boiler, and Home Assistant is controlling the whole thing. Everything works perfectly and I could implement some features that simply no system would have done out of the box, for example in rooms where there's combined UFH and radiators I can drive both heating systems when the target temperature is far from the desired (so that the room heats up quickly) but as the room temp is getting closer to the target, the radiators are turned off so that UFH dominates heating (more comfortable and more energy efficient than radiators). In rooms with radiators, temp is +- 0.4 C within target, in rooms with UFH, it's +-0.1C within target.
Yeah, the automated/remote controlled heating system world, and also the ringbell world is basically a giant scam, since they are updates on world that also scammed you in the past. I cried when I shelled out so much money for my Tado device, but even a dumb bTicino device costed in the hundred of euros realm, and it's just a sensor + a small LCD display and a designed-in-hell menu system to program it. And the same happens in Ip-based ringbells. A Doorbird will cost you hundreds of euros for what is basically a webcam plus some nice metal casing and a shitty software, but it competes with analog systems with optic cables etc that cost basically the same or more.
Off the shelf systems aren't only optimised solely for efficiency. They're made to be simple enough that an installer with half a day's training can do a few multiplications and additions to set the parameters that'll give you a tolerable percentage of optimal in the situations that equipment is specified for -- while still being understandable by the next guy. This nearly always means things are a bit oversized and inefficient to account for the things that the simple models are missing.
Almost everything in engineering is like this, not just heating. It's pretty rare that something is fully optimised.
> We've moved to an new apartment (house) and we had to do a full renovation. It doesn't have modern insulation and I calculated that for the time being the ROI on insulation isn't worth it.
You calculated wrong, guaranteed. Most likely, you wildly underestimated fuel/electricity costs.
> After spending a few hours of understanding the setups that "experts" have recommended, I figured out edge cases where they would be either wasteful or uncomfortable (meaning: unnecessary and inavoidable temperature overshoots or undershoots, etc.).
Instead of thinking "the entire HVAC/heat industry are idiots who can't do any of this right", maybe you should take a look in the mirror and consider that your assumptions and/or criteria are wrong.
For example: under/over shoots in a modern HVAC or heating system will not cause any "waste" or discomfort. 1-2 degree F in overshoot does not mean the space will lose appreciably more heat than if it had perfectly regulated at the setpoint. You also don't want a system that responds instantly. Let's say you open the door to receive a package, and you're signing paperwork, etc. You close the door. The air in the room is substantially cooler.
Should the heat turn on?
I bet it does in your home...but the correct answer is no, because the air will warm up rapidly from all the objects that were at the temperature of the room. Thousand-plus square feet worth of surface area...
> I could not have been more wrong. After spending a few hours of understanding the setups that "experts" have recommended, I figured out edge cases where they would be either wasteful or uncomfortable (meaning: unnecessary and inavoidable temperature overshoots or undershoots, etc.). I had many-many rounds with Honeywell, Tado, Siemens, etc. and every single one of them had _major_ issues.
Temperature hysteresis is unavoidable with a conventional thermostat, but you can reduce it with PID controllers. Most commercial building automation systems use PID controllers extensively.
My guess is that the residential options from Honeywell, JCI, Siemens, Trane, Carrier, etc are focused more on one-size-fits-all applications, whereas commercial BAS systems are more or less bespoke designs for a specific building (using commodity sensors and controllers). I work with all five of the aforementioned companies on building automation projects, FWIW.
Sounds like a nightmare for a future buyer to operate.
Some people are unlucky enough to buy homes where a machine engineer designed the boiler setup and the boiler room have enough valves and manometers to like operate the engine of Titanic.
I guess programmers are the new sinners in this area nowadays.
If we ever sell this (which we don't plan to), I know what to install (it'll be quite good, just not this perfect). I have it in a cupboard (a Siemens Connected Home thermostat system), the downside of that is that the combined UFH+radiator rooms will be less comfortable.
(But still more comfortable than 99% of the houses I've been in.)
I haven't mentioned in the parent comment but as a test I've dismantled the HA system and installed the Siemens system and it works well, just not 'perfectly'.
For every John Siegenthaler and Dan Holohan, there are thousands of mechanical engineers and tens of thousands of plumbers who are happier to slap in a $20K 4-hour boiler retrofit. There’s not enough extra money in catering to the 0.1% of homeowners who care about the details.
It’s a service or human engineering problem rather than a mechanical engineering or knowledge problem.
Contractors today put in over-sized equipment, set flow temps higher than needed, undersize emitters for aesthetics and cost, and run pumps at full speed to avoid callbacks for “it’s too cold”. You can’t afford the windshield time to drive over to tweak the system to extract maximum performance, because homeowners don’t want to pay for it and will go with the lower bidder enough times that your premium AI-powered service will struggle.
I’ve tweaked my reset curve 12 times the first winter and 2 more times since then (counted from my spreadsheet).
Realistically, if I gave up on the last 3% tweaking, we could have lived with it after 2 post-install tweaks, but at least one of those had to wait for seriously cold weather snap to fine-tune the low end.
My spouse would happily agree that the house is finally very comfortable and noticeably more than before. She’d also tell friends who asked that there were a few days the first winter where the house wasn’t warm enough and needed an adjustment. People who heard that story might conclude that their neighbor’s guy who never has a callback for “too cold” is a safer bet.
Over time, I think even the best mechanical contractors will start to lean towards avoiding callbacks and do that by running the system 5-10°C hotter than “correct” engineering requires. That’s still better than today, where flow is set to 80°C, pumps to max, and the thermostat cycles 4 times an hour but the house is never too cold.
a bit off-topic: Are you running a single boiler and if so, how are you mixing UFH with radiators given there's a ~20C difference between the recommended temps for the two?
My knowledge is that for UFH you run at temps between 40-50C and radiators run at 60-70*C.
As someone who lived in multiple rich countries in Europe, let me tell you that the German healthcare system is awesome. It has a lot of problems, but it's head and shoulders above many-many other countries. You can actually get care by a qualified doctor, while this is absolutely not self-evident even in rich countries like the United Kingdom, and let's not talk about CEE countries.
I would disagree. German doctors regularly prescribe homeopathic medicine, misdiagnose patients and tell people they just need to drink tea, and also will not supply medicine when it is really needed. This is well researched.
Saying you can not get care by a qualified doctor in the UK is a completely false statement.
There's not much to see here I believe - Tesla's valuation is approximately where it was before the election, and that's generally true for tech stocks (Tesla generally moves with the NASDAQ). It made a big swing in the last month, but the news around this is classic post-hoc narrative.
Edit: I meant the crashing valuation, not this particular news, apologies for the confusion. I do think that government officials promoting stocks is a terrible precedent to set.
The president of the United States is now pushing individual stocks with his cabinet because his billionaire buddy is having a bad time, and the response is “nothing to see here, perfectly normal”???
The Trump administration's active and overt effort to prop up the stock suggests to me that they're worried. The president himself made a video advertorial. It's bizarre.
Sad to see Hacker News turn into Reddit, flagging the only informative comment because it does not validate the mob's hatred. This headline is meaningless, and by the way, $TSLA has shot up alongside the US tech sector and is now positive. Will we get updates on the front page every five minutes?
Whether the comment is informative or not it dismisses the news article without even tackling the actual issue which is the commerce secretary recommending the stick for which the presidents closest advisor is the CEO/largest shareholder.
I disagree with the downvotes but it is very close to distracting the actual issue at hand by dismissing the more minor issue which is the stock price movement.
That's certainly a more interesting topic of discussion, but this submission is not about the issue that you and I would rather discuss, it is about short-term movements in the price of a stock that moved in the same direction as the S&P 500 and the NASDAQ.
I’m going to be honest, I try to assume good faith from others on this forum but your comment makes that particularly difficult. By “issue that you and I would rather discuss” are you referring to the Secretary of Commerce’s unprecedented public endorsement to buy a specific stock, of which the President’s primary advisor is the majority shareholder? Because if that’s what you’re suggesting well, that’s pretty wild. Especially considering the second paragraph of the article highlights exactly what the article is about:
“Why it matters: Cabinet secretaries don't typically recommend individual stocks, much less those linked to the president's closest adviser.”
To whoever downvoted this. I used to come to hacker news years ago and see 90% programming related things: Type system abuse, extreme common lisp code, libraries and tools. It was pretty much all tech debate all the time. The worst days would be 70% tech. Today thats a good day.
Nowadays theres a lot more californians being mad at elon, poetic eulogies, paid articles about "how to write good" or how "you should write even if people dont read it."
People will try to say it hasnt changed but it has changed. It is about half as tech related, and about 10 times as reactionary in the same way the rest of the internet has become more dumb.
You can be mad if you want, but everyone can see it, and thats why some people I know in real life are referring to hacker news as orange reddit in a denigrating way. Reading hacker news doesnt confer programming street cred like it did ten years ago. That isnt because im cynical, or want it to be true. It just is true.
I've looked around (Europe), and there's nothing comparable at the price, except maybe Ioniq (but I didn't like the ergonomics, not saying it's objectively bad, just didn't fit me). Kia is way more expensive, Volkswagen is way more expensive at the same trim level, etc.
>I'm more interested in knowing if there are any glimmers of hope left in Hungary.
Absolutely. In my opinion, our lifeline is the EU, as much as Orban is a pain in the ass for them. I believe that as long as Hungary is part of such international organizations, and I'm counting the NATO here as well, Orban can't cross certain borders, or at least not without repercussions, and I believe that he doesn't want any, since his whole shtick is to capitalize on these relations. For example, the same developments would have been (are?) much more scarier in Turkiye, or Belarus.
According to propaganda, Orban is building a family-friendly place. This is proclaimed loudly in the media, and at points where you enter the country (like metal signs saying "Welcome to the family friendly Hungary").
These family values is the usual alt-right dogwhistle, however. Same as how it's used in the US: https://en.wikipedia.org/wiki/Family_values#Organizations . In reality, the systems that actually support families, healthcare and education, are more strained than ever, due to the gov increasing their responsibility, and underfunding them constantly.
Couples are pushed to marry and have children, by providing discounted loans for them, if they sign contracts that they will bear children. Up to three, the more children they sign up for, the higher the loan will be.
They have amended the hungarian constitution to say explicitly that the mother is a woman, and the father is a man. The particular part now reads: "Hungary protects the institution of marriage as a voluntary union between a man and a woman, and the family as the basis for the survival of the nation. The basis of the family relationship is marriage and the parent-child relationship. The mother is a woman, the father is a man."
"The West" and progressive societal values are actively framed as harmful propaganda that intends to destabilize the country. Values like supporting women and lgbt+, supporting investigative journalism, having a look on migration as anything other than "very harmful".
Abortion laws are strictened. They included things like the mother having to listen to the fetus' heartbeat, before agreeing to the abortion procedure. Frankly, I think this is so evil, that I have a very hard time not to write something that wishes active harm towards these people.
Doctors don't take women seriously, and are often hostile or degrading towards them. This is not a politically directed issue, rather the result of the previous 50-100 years of political climates. For example, a female friend of mine went to a regular checkup, where the PRIVATE, for-profit gynecologist asked her if she has children, and when she said that she doesn't, and that they don't plan to have children with her husband, the doctor recommended that she reconsider, and that he can organize it that she gets pregnant, despite what the husband wants.
Hungary has a significant Roma minority. Many of the Roma people live below the poverty line, and their relation to the Hungarian population, government and law enforcement is a systemic, centuries-old issue. The current government does exactly nothing for them, nor in the short term nor towards their long-term well-being, but uses public figures of their culture to signal their support and association, and buys their votes with cheap gestures right before the elections.
LGBT people, and issues are not just marginalized, but the movement is branded as something that actively destroys society. LGBT families are regarded as unfit to raise children, they can be life partners with some of the marriage benefits, but not in a recognized marriage, and the Pride parade has been floated as something to be outlawed just this year.
These are just from the top of my head, in 30 minutes. Please feel free to ask any follow-up questions or proof, or post clarifications and corrections, I'm sure there are mistakes, and I don't intend to have any, as the well-being of my fellows is dear to my heart. Thanks for reading.
I've always admired Hungary and Hungarians. Very prodigious people. Neumann, Erdős, Teller, Szilard, Grove, Simonyi. Is there a country that breeds more geniuses per capita? How comes Hungary's political situation came to this?
I didn't read them all, but I read enough to think they were lying about it being tweets from 2017. It reads like someone asked ChatGPT to summarize current political news in the US.
History may not repeat, but it absolutely rhymes. If had a nickel for every time I heard about a government proposing to round up and deport thousands of people to a special island just so that their normal Constitution rules wouldn't apply, I'd have two nickels--which isn't a lot, but it's weird it happened twice.
Unfortunately, remote detention camps to "keep the homeland clean" are nothing new, they are tried and tested.
Here in Europe, we have had the UK and Italy actively pursuing rounding up migrants and deporting them to Ruanda/Albania until their claims are processed, and Australia has been doing this for decades now on Nauru and other places.
Possibly the migrants could enter the country using the approved legal process instead of just wandering in?
It isn't reasonable to expect countries to have a generous welfare system, accept all arrivals and exist on the same planet at the billion-odd people who live on a few dollars a day. Something has to give. I vote the welfare system but keep getting overruled; so one of the other two has to go. And we don't have the space tech to pick option 3.
> Possibly the migrants could enter the country using the approved legal process
At least for America, many if not also the majority did just that... And then overstayed the time limit, which is a civil infraction in the same category as a parking ticket.
Republicans have proposed a special "come deport me" registry where not-signing-up is itself a felony, as a roundabout way to retroactively criminalize things.
> Possibly the migrants could enter the country using the approved legal process instead of just wandering in?
For Germany, there is no legal way to enter the country if you're not caught by one of the larger dragnets (evacuation of personnel in Afghanistan, EU-wide assistance for Ukrainians and a few other rare international resettlement efforts). You are not able to apply for asylum outside of Germany, you cannot fly to Germany without a visa (the airline just won't take you as a passenger).
On paper yes you have the right to claim asylum. In practice, you have no way that doesn't make you commit at least one felony along the way.
I know nearly nothing about German law, but I going by what you write if Germany doesn't make it legal to enter the country, then no surprise the people who try anyway run the risk of being deported. I have enormous sympathy for them, but the fact is Germany is famous for having a big welfare system. That means people can't just wander in.
The thing for us to do would be to not make it necessary for people to flee in the first place. Feeding them in Africa is cheaper than feeding them here, the 2015 migration movement was largely caused because of a 100M $ shortfall in UNHCR / UNWFP food supply.
What are you going to get instead? I think that Chinese EVs are flooding the market but it's absolutely not better to support China than supporting Tesla. Hyundai/Kia - maybe an option, primarily because people don't know that much about South Korea :)
I find it very sad that purchasing a car from a publicly traded company with tens of thousands of employees is somehow interpreted as supporting the politics of the CEO of said company. Life shouldn't be politicised that much
> it's absolutely not better to support China than supporting Tesla
I disagree. Right now, I wouldn't criticise anyone who buys a Chinese EV. But I would put stickers of Musk doing his nazi salute on Teslas I find in the streets.
> Life shouldn't be politicised that much
That's what one says about political topics that don't impact them. Go tell Ukrainians that they should buy Russian products because "life shouldn't be politicised that much".
> But I would put stickers of Musk doing his nazi salute on Teslas I find in the streets.
I know people who were so upset about the other side (in that case, Republican voters) that they said that they (the other side) should be deported from the US. I think this level of mania is too much and it is the real life manifestation of what people do on the Internet. I recommend that you put a sticker on the car when the owner is there, and look them in the eye.
> Go tell Ukrainians that they should buy Russian products because "life shouldn't be politicised that much".
I am likely much-much closer to this problem than you think (personally and physically), and I absolutely think that what's happening in Ukraine and what is happening in the US right now is incomparable.
You know, Ukrainians and Russians still live and work closely in many parts of the world because they can differentiate between Putin and the person who's in front of them. You're not beating Elon with your stickers, just screwing up a day of a random human person who has bought a car they liked.
Yes it is sad, but the stakes are too high to ignore. I don't know where you live but in Europe most people are very disappointed in recent actions by the US. Any decision, from small to large, now should factor in if it benefits Europe or the US. It is a matter of being reciprocal.
Musk is the one politicizing it that much, we're just responding to it. If he shut up and stopped his nonsense, it would quiet back down.
I almost never judge a work by it's creator, but sometimes the creator really goes out of their way to make me ignore that principle. Musk, Kanye, and a handful of others.
> I find it very sad that purchasing a car from a publicly traded company with tens of thousands of employees is somehow interpreted as supporting the politics of the CEO of said company.
I'm sure there were also good people in IG Farben who just wanted to get through their day during WW2, right?
Nobody would bat an eye if some random shmuck on the Tesla manufacturing floor held some silly ideas, but arguing that the extremely public facing CEO of a company gets a pass because he's just one of many at a large firm is a wrong take, I'm sorry.
The CEO is the company. If the janitor posts a silly youtube video doing a sieg heil, the janitor is in trouble. If the CEO of the company does a nazi salute, the company is in trouble.
The ethnic cleansing Uyghur concentration camps are probably the biggest one. Also threatening Taiwan, which is a lovely country I would hate to see destroyed. Besides that the social control the government exerts is pretty frightening to me (I've lived in China).
All that said I still see China as less of a direct threat right now.
Some good points, I was aware of them, but comparing to the current US it doesn't seem as bad.
I just don't know how bad the Uyghur was/is considering the propaganda that both sides would push, with China not letting independant investigators or reporters do anything in and the whole US manufacturing consent media and US government propaganda. Then them calling it a genocide while Palestine is not.
You do realize that most of this is US propaganda, right? Xinjiang is like a fully developed economy and Uyghurs are doing well. I visited Beijing last summer and asked some Uyghur workers who discussed their conditions openly.
The re-education camps were for a small part of the Uyghur populace that were involved in terrorism against other Uyghurs and Chinese.
>I find it very sad that purchasing a car from a publicly traded company with tens of thousands of employees is somehow interpreted as supporting the politics of the CEO of said company.
But this is the reality, parts of your money go to the CEO salary, and if the sales are good the CEO will get a giant bonus that he can use to buy a president/dictator and convince them to do super insane shit.
There was a news yesterday where twitter AI system prompt had a filter for Trump and Elon, they were caught and they reversed it, IMO that topic should have been a bigger thread here
The current within a single cable is something like 25 A according to der3uer's measurements. That's crazy for those thin cables. So if current distribution is so uneven then no cables will be completely safe IMHO.
Absolutely not being sarcastic: one problem it solves is that it is very hard to read as a beginner, so it can be intimidating (although it becomes much easier to read a bit later). This, coupled with the general arrogance of k/q practitioners (again, not really saying this in a negative way) and that k, kdb, etc. deliberately doesn't give you guardrails makes people who write k/q seem a bit 'mythical' and make them feel very clever.
So I think k, q and kdb are fun to work with, but one of the major components of its success is that it allowed a community (in finance) to evolve that can earn 50-150% more than their peer groups who do the same work in Java or C++. 10 years ago a kx course cost $1500 per person per day.
To note that those are typical prices for enterprise level certifications, including some products that some Java or C++ devs might need to interact with, when working on those kind of environments.
> Are people really locked out of LLMs due to price?
Yes. For example Google has just made Gemini a standard part of Workspace, before that it cost $36 or something per month per user. That was too much for many SMBs to experiment with (you and I understand that the potential efficiency gains are way higher but for an SMB, paying 4x more for your office suite sounds bad).
The reasoning: when you heat up the house, then your boiler needs to produce constant high-temperature water. When you keep the house at the same temperature, then the boiler produces much lower temp water and it is more efficient.
Insulation also matters because if your house has outer insulation then it means that heat transfer from the house to the environment is mostly blocked, but cross-room heat transfer is likely not (through the walls). Therefore it is better to heat the whole house than heating just a couple of rooms because if you do the latter then you'll end up heating the whole house anyway but you're using less surface area (meaning you need higher flow temperatures, meaning less efficiency).