So, Alec over the Technology Connections channel made an hour long video explaining the difference with kW and kWh (obviously with other stuff around it).
I’m living in northern Europe in an old house, with pretty much only electric appliances for everything. We do have a wood stove and oven, but absolute majority of our energy consumption is electricity. Roughly 24 000 kWh per year.
And, while eveything he brings up makes absolute sense, it seems like a moot point. In here absolutely everyone knows this stuff and it’s all just common knowledge. Today we went into sauna and just turned a knob to fire up the 6,5kW heaters inside the stove and doing that also triggered a contactor to disengage some of the floor heating so that the thing doesn’t overload the circuit. And the old house we live in pulls 3-4kW from the grid during the winter just to keep inside nice and warm. And that’s with heat pumps, we have a mini-split units both on the house and in the garage. And I also have 9kW pure electric construction heater around to provide excess heat in case the cheap minisiplit in garage freezes up and needs more heat to thaw the outside unit.
And kW and kWh are still commony used measurement if you don’t use electricity. Diesel or propane heaters have labels on them on how many watts they can output right next to the fuel consumption per hour and so on. So I’m just wondering if this is really any new information for anyone.
I assume here’s a lot of people from the US and other countries with gas grid (which we don’t really have around here), is it really so that your Joe Average can’t tell the difference between 1kWh of heat produced by gas compared to electricity? I get that pricing for different power sources may differ, but it’s still watt-hours coming out of the grid. Optimizing their usage may obviously be worth the effort, but it’s got nothing to do with power consumption.
So, please help me understand the situation a bit more in depth.
People complaining about this video have clearly not watched much Technology Connections; I enjoyed it immensely. It’s right in line with how Alec normally does his videos. We who are loyal to the Great Alec expect the pedantic content.
In here absolutely everyone knows this stuff and it’s all just common knowledge.
Also check out his other video on his Connextras channel where he basically suggests dismantling capitalism.
So I’m just wondering if this is really any new information for anyone.
It’s never wise to underestimate most people’s ignorance.
I started to watch this video and gave up mid way. It spends like 15 minutes on gas stoves. Maybe I’ll revisit it.
Btw, I really liked his other video on microwaves.
kW/kWh aren’t commonly used outside of electrical applications in the US, so people are less readily able to quantify and compare in other contexts. Looking at a variety of natural gas companies’ bills, you’ll get volume multiplied by a therm factor instead of simply using kWh; horsepower for not just cars but even electrical motors and pumps.
I think the average person will have looked at their electricity bill and put the basics together about watts and watt hours. As for comparison with natural gas, I think he didn’t touch on the real metric people then turn to- cost. Depending on the state it can be much cheaper to use gas vs electricity.
Yeah, electric motors are what I notice the most. Be it on washers/dryers, garbage disposals (which range from 1/3, 1/2, 3/4, 1HP) and more.
Saved you a click: power = rate of energy use (energy/time)
He says it so many times in so many ways that he actually starts to make it seem more complex than it is. You start wondering if you’re missing something, because you got it in 6 seconds but 12 minutes later he’s still talking about it.
I haven’t watched it but its really simple. If you receive 1kW within 1hr and you compare that amount of power to 1kW over one second things are much different. The first is like a nice heater in a cold winter night…nice steady energy, a little bit of power. The second is like hell hole, tons of energy but still only a little bit of power. Power is the ability to do work or simply move things. Energy is the total amount of moving things regardless of the actual power used. So if you toasted a toast, that was a lot of power delivered quickly, but you could also do all that work slowly over centuries and eventually end up with the same molecular arrangement using the same amount of energy.
“1kW within 1hr” isn’t power. That’s energy.
“nice steady energy”? You mean nice steady power, right?
“The second is like hell hole, tons of energy but still only a little bit of power.” No. They are both precisely the same energy.
“So if you toasted a toast, that was a lot of power delivered quickly.” No. That is a lot of energy delivered quickly.
I typically wouldn’t be pedantic about this, except that this is precisely the point the video is making. These two unit types are often confused.
“1kW within 1hr” isn’t power. That’s energy.
The watt is always power, not energy. I’m assuming OP here got some prepositions mixed up and meant 1 kW delivered for 1 hr. That amounts to an energy of 1 kWh.
The second is like hell hole, tons of energy but still only a little bit of power.” No. They are both precisely the same energy.
No, they are the same power. The energy in the case where 1 kW of power is delivered for 1 hour is 1 kWh. The energy in the case of 1 kW delivered for 1 s is about 0.28 Wh.
If instead 1 kWh was transferred over the course of 1 hour, that is an average power of 1 kW (but does not have to be uniform, without more information we can’t know the power profile). If 1 kWh is transferred over the course of 1 s, that is an average power of 3.6 MW which is the example I think OP was getting at (ref. hell hole comment).
After watching the video it was a bit over explained. I think he got his point across in the first 10 minutes, though I am an engineer by trade.
I appreciate his rigour in explaining and it is a good refresher on the power/energy calculations.
is it really so that your Joe Average can’t tell the difference between 1kWh of heat produced by gas compared to electricity?
Most people don’t even know what a watt or watt/hour is. And have no idea how energy from gas relates to energy from electricity.
watt/hour
Oh yeah I’ve seen that used before, makes me cringe every time.
Anyway, do must people not go to high school? Or is stuff like that not part of the physics curriculum in some places?
Even if it was covered in high school, I think because most people never use it again in daily life it’s easy to forget.
A W/h either is a big problem or will be soon.
I mean that depends on the sign of the W/h as well as your W/h2 and higher orders too. Maybe you’re actually approaching zero watts :P
In my highschool physics was optional. You had multiple options for science credits and could get through without taking it.
Oh, in my country you have to take physics, chemistry and biology. That actually goes for middle school too. Plus geography which actually also contains geology. And math could be considered science I guess.
We have elective courses too, but all the basics are mandatory. That includes at least two foreign languages, history, our own language, literature (becomes separate subject from language in high school), music, art (including history of both), basic computer usage, shop class for boys and home ec for girls (with trades in between so us boys still got to cook and stuff, plus in elementary school everyone gets to knit and crochet IIRC). Oh and physical education unless you’re disabled, in which case you either get to watch or just do something else I think.
I’m actually sure I’ve missed something. These are all mandatory. You can do shit like folkdance or choir for electives, or many other things depending on school. I had philosophy as one of my electives lol
I think people in some countries (the US) don’t even know what they’re missing out on tbh.
I never took chemistry, and I didn’t take a real physics course until college, though we had survey courses like “physical science” throughout school.
I don’t recall if we talked about watt hours specifically, but joules were certainly mentioned, though I doubt most people remember it. Most of the emphasis was on things like friction equations (given an ideal pulley and an incline with slope…), not real world things like understanding your electricity bill.
That said, I think most people intuitively understand the difference between instantaneous consumption and total consumption over a time period. They know playing games will drain their phone or laptop battery way faster than browsing the web, for example. They just tend to not stop and think about it and they simplify things in the wrong way (power rating on device), though a total energy estimate does work (e.g. when comparing refrigerators).
In our case, we had the pulleys and stuff too, but we had different modules and the later ones showed how they connect to eachother, so you start up with optics, mechanics (as in movement, not car parts lol), thermodynamics and electricity in middle school, then you get all of the same with a lot of new information in high school and also very basic nuclear physics, like atom models, electron levels and stuff. Essentially first you learn about power and energy in the context of movement and thermodynamics, and then later also electricity (at which point you’ll understand how heat at the power station converts to electrical energy at your home car charger converts to movement of your electric car, or similar with fuel and internal combustion engine car - of course the efficiencies are simplified greatly).
Of course you heard a lot of bored classmates go “But why do I have to learn this, I’ll never need it in real life”, but at least electrical bills are so much easier to predict when you know how power and energy relate.
I’m very happy with how the education system in my country works and how it prepared me for university (which I just didn’t have the attention span for) and life. It’s the reason I’m OK with paying a fair bit higher tax than I would in some other countries. Our income tax is at 22%, but a bunch is hidden from regular peoples’ view by making it part of the employer’s tax burden, meaning if I pay myself a decent salary, the tax rate is ~43% or if I pay myself less than I need to live I can make it 31-33% and get a visit from the taxman asking why I’m paying myself so little and paying the rest out in dividends. Luckily the economics course in high school included our tax system in addition to macroeconomics concepts, so I can navigate all this fairly easily. Not sure if that one was mandatory nationwide, or just part of my own school’s curriculum, because we basically had 3 types of subjects: Absolutely mandatory (like 60% of total course load), school specialty curriculum (like 20-30% of total) and then the rest was up to you to choose what you wanted to learn.
However, now they’re talking about making universities charge tuition from everyone as well as all kinds of cuts in other sectors WHILE raising taxes, despite the fact that we barely even use debt as a nation so if all that happens, I’ll find some creative ways to reduce my taxes or pay them in another country.
Okay, long ADHD rant about our education system aside, I do agree with you that most people will probably intuitively understand the differences. But man do I feel like some countries’ curriculums have been half-assed. It’s entirely possible to give young people an understanding of the universe from astronomical scales down to microscopical AND teach them things like tax systems, energy consumption calculations and other things that can be used in real life.
In our case,
Yeah, we had all that stuff too. This was many years ago, but I remember the electricity section being fairly basic, as in mostly covering how volts and amps interact (i.e. high voltage, low amps is way worse than low voltage, high amps, in terms of safety). And that’s really about it. Maybe we covered other stuff, but it really wasn’t important to go further, probably because I went to school before EVs and whatnot were commonplace.
I think my education was quite good. I was very much prepare for the university I went to, but that kind of meant we skipped some important stuff. For example:
the economics course in high school included our tax system
We didn’t really learn economics or taxes in high school. I mean, we discussed basic supply and demand, but that was more in the context of history than anything actually applicable to life (i.e. Great Depression’s impacts on supply and demand). I learned the vast majority of what I know about economics, investing, and taxes on my own because I’m interested in it. It just didn’t seem to make the cut for high school, where we learned a wide variety of other stuff, like biology, math, history, English, etc. A basic high school day was broken up into 6 periods, usually consisting of:
- math - start w/ geometry and end at pre-calc or calculus (depending on which track you took)
- history - US, European, world, etc
- english - literature, writing, etc
- foreign language - needed 2 years; select between Spanish, German, Japanese, or French (maybe one or two more); the other two years were electives IIRC (but more restrictive than the next group)
- electives - PE, shop, etc; there were several options, no guarantees as to what people took
- science - biology, chemistry, physics, etc
I did two years at the high school and two years at the local community college so I could get a 2-year college degree at the same time as my high school diploma. That was pretty rad, but I wonder if maybe I got super compressed education since I had about half the class time as my peers (about 3 hours/day vs 6), but we had more reading at home, which I think made up for it (I’d spend 3-4 hours/day studying vs 1-2 hours from regular high school).
However, at the end of it, there were some gaps:
- didn’t know how taxes worked - pretty easy to learn later, but I did need to teach myself (I think we had a PF elective option)
- didn’t know how economics worked - basically anything at the government policy level was a black box - we covered basic supply and demand, but not how the fed creates money, tariffs, etc, outside of some brief mentions in US history
- very basic overview of how consumables like electricity and natural gas work - i.e. what a watt hour is, or how to compare electricity and gas; school mostly stuck to principles and theory, not practical things like understanding your gas bill
I don’t think that was a failure per se, it just wasn’t deemed important since the whole point of high school was to prepare you for college, and anything that didn’t help with that seemed to get dropped. I think this is unfortunate, and that high school should have you ready to make a decent wage outside of school (i.e. finish w/ marketable skills, like the German system does).
Absolutely mandatory (like 60% of total course load), school specialty curriculum (like 20-30% of total) and then the rest was up to you to choose what you wanted to learn.
Yeah, we were pretty similar, except we didn’t have “school school specialty curriculum” since I went to public school, and public schools are standardized in what they teach. So we had something like 70-80% as mandatory curriculum, which prepares you for college, and 20-30% electives, which hopefully prepare you for life. I did shop (make stuff out of wood), home ec (cooking), drawing (nearly failed, I suck at art), and visual communications (graphic design, photography, etc survey course).
He’s making a point about instantaneous versus overall energy use, which it sounds like you already understand. “Power” and “energy” are already kind of loose terms, which could make that conversation confusing IMO.
But for anyone confused by this:
For the typical energy consumer, Watts (W, kW) are relevant when considering circuit capacity. Otherwise, Watt-hours (Wh, kWh) is likely the metric you’re looking for when considering energy use.
Concretely, your coffee maker might pull 1.2 kW while in use, more than most appliances in your house, yet it probably represents a minuscule portion of your electric bill, perhaps less than 1 kWh, since it only needs to boil a small amount of water with each use.
How are energy and power “loose terms”? Energy might be difficult to fully explain rigorously, but it’s one of the fundamental elements of our universe. And power is just energy over time
How are energy and power “loose terms”? Energy might be difficult to fully explain rigorously, but it’s one of the fundamental elements of our universe. And power is just energy over time
Well, you yourself just provided the example, since your definition of energy and power are the inverse of the definitions used in the video.
It’s the fact that people use them differently or interchangeably that makes them “loose” IMHO.
There’s no way even 1% of people understand this in the world. Maybe 1% know of those measurements “existence” asking them what they are would get an “uhh”
In the world? Me and millions of other people got this info in middle school physics. Sure, maybe we mostly forgot the details by now. But it’s not arcane or ancient knowledge lost to time. It’s in your electricity bill every month. A quick visit to Wikipedia and I got the gist of it back. Every single physicist, engineer, and electrician got this explained again to them.
“a quick visit to wikipedia” is a good example confirming what I said, majority of people are not willing to do that to learn any subject. 0.483% of humans are engineers, of that I’d say there are a small chunk that are near worthless and probably don’t even know these basics.
It’s in your electricity bill every month.
You get a comparison of electric vs natural gas flow in your energy bill? Wow!!
I think most people understand W vs kWh, at least on some level. They know things use different amounts of energy depending on what it’s doing (i.e. a microwave sitting idle vs actually warming things), but they may not be comfortable estimating kWh from watts.
But that’s only the first part of what OP talked about. The meat of the discussion was about energy stored in something like natural gas vs electrical energy. How exactly am I supposed to compare a gas furnace and electric AC vs an electric heat pump? Not only would I need to somehow convert therms (or whatever local unit you use for gas energy) to kWh, but I also need to understand efficiency of heat transfer for heat pumps, which will vary quite a bit based on the weather (much less effective in cold weather).
That’s complicated, and many HVAC professionals here don’t like heat pumps for whatever reason so they tend to think in terms of resistive heating vs gas heating, which is absolutely wrong. I want a good idea of cost difference between gas furnace + electric AC vs a heat pump, but that’s not something I have easy access to.
You get a comparison of electric vs natural gas flow in your energy bill? Wow!!
I mean, there are countries where natural gas is billed per kWh. And the OP said
And kW and kWh are still commony used measurement if you don’t use electricity. Diesel or propane heaters have labels on them on how many watts they can output right next to the fuel consumption per hour and so on.
Follow-up video idea: speed ≠ distance
Yeah, what the hell is this video subject. I honestly thought this stuff was common sense.
Should be but search for “kwh per hour” and there’s plenty of people who seem confused by it all.
The one that I think more people misunderstand is temperature Vs heat Vs something feeling hot/cold. One is a property, one is energy, and the other is the transfer of energy.
You know a nation of people who may not be able to articulate their understanding, but definitely have a high intuitive understanding of that?
We Finns.
100C sauna and no problem sitting on wood, but happen to touch something metal and oooh-weee.
Also same thing happens the others way around when it’s - 20c outside. I don’t think there’s many people in Finland who don’t have a core memory of what cold metal tastes like in winter, because of the resulting trauma. And it doesn’t even need to be metal to stick.
Nicely explained.
100C sauna???
It’s perfectly commonplace to have at least a 100 degree sauna.
I think something like 140 is around the hottest I’ve been in.
The air is that temperature, but there’s also a ton of moisture in the air. You can take it for a few minutes at a time, then optimally you go take a dip off a pier into a lake or the sea. When I was in that 140c sauna it was a proper wood heated large sauna at my confirmation camp, it was on an island in the Baltic so we could run out the sauna and jump into the Baltic Sea. It wasn’t warm at all, but the intense heat of the sauna having warmed all the top tissues and muscles, you get a sort of immunity to the cold. Which lasts for a little while, and when you start getting cold enough, you go back to the sauna, and because the cool water has now cooled the skin and muscles, you get a resistance to the heat for a while.
Rinse and repeat. Literally.
This cycle supposedly has benefits for circulation and muscles.
And having done it ton in my life I don’t doubt that at all.
Usually I have to settle for the sauna in my apartment though. (I live in a cheap rental but a sauna is default in pretty much all buildings built after the 90’s.) And then either going to balcony to cool off a while or take cool shower. It’s not as nice, but it’s more or less the same.
Although I don’t rip the most out of my electric stove to get the most heat. I have it set on pretty low and I just use a lot of löyly. Probably I’d say my normal saunas are maybe around 90-110 degrees at the most. A sauna below 80 degrees is considered a “Swedish sauna”, which is to say we mock them as not being strong and manly as us and so Swedes would be afraid of having a “proper” sauna.
And to be honest the Swedes are pretty on board with this whole stereotype I guess, seeing us as mute emotionally distant brutes. Here’s a cool Swedish commercial featuring a Finnish man. They made it. (that’s not the real title though just the yt video title)
I’d really like to try that someday
I believe, internationally, lots of places which have saunas also have pools or even cold pools. I imagine. Like high class gyms or smth.
But I’ve heard several stories of Finns being abroad and going to a sauna and being prevented from tossing water on the stones (löyly = it’s sort of the water and the heat that results from throwing it, roughly how you’d use “gas” in relation to cars, more gas can mean more petrol or pressing on the gas pedal harder, that sort of word), and the employees saying “you can’t do thaw to it’ll break the stove” because they don’t understand how saunas work.
And to do this to the best effect you need a proper löyly to the point you pour cold water from the löyly bucket on top of your head to bear it for a while longer for all the muscles to really warm up. And then for maximum shock quick jump to cold water, or sometimes just a snowbank. That’s common as well. Hurts like bitch though if you do it with the wrong kind of snow, like jumping on a bed of freezing razors. (The top of snow that was quite soft earlier had frozen and I didn’t see it in the dark and jumped into the bank and there was like a half an inch of raspy ice on top before I broke through to the softer snow. Or I just didn’t care being either so young as not to or so drunk as not to. Probably both.)
And if you’re gonna throw a strong löyly, or even löyly at all in a public sauna, it’s proper etiquette to ask for consent from everyone. Although now that I wrote that I have a feeling asking for consent in some non-Finnish public saunas may have a different meaning, as far as I’ve understood from popular media.
Power is water throughput in a pipe, energy is water filling a bucket. Simplest way I’ve found to explain it in my 15 years in the energy space.
Power is a measurement of the velocity and volume of water flowing through a pipe at a given instant*
I’m so sorry, I am officially ‘that guy’, taking a simple analogy and making it annoying…
