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.
In here absolutely everyone knows this stuff and it’s all just common knowledge.
Fair point, but basic physics has been a part of our education program for at least 60 years. Also for few years the ‘exchange priced’ or ‘market valued’ electricity has been somewhat popular and on the news, which adds up to the general understanding as if you know your stuff it means quite literal money as your bills are smaller. So, maybe ‘absolutely everyone’ is a bit of a stretch, but in general the majority of adult people understand the concept.
And also a ton of common folk understand it at least a bit on a deeper level as basic physics is included to studies beyond elementary school regardless on what you study. Sure, not everyone understands (or cares) how 3 phase AC in here adds up to 400V or why you need to have 2,5mm² wires for 16A fuse, but it’s still pretty common that people, specially in a separate house, understand how you can only pull 2300W out of a 10A circuit or 3600W from a 16A one (10 and 16A being the most common fuses in a household in here).
If you think the average person understands watts, you live in a bubble, straight and simple. You have a very skewed notion of the average person.
We live in a world where people demanded (and succeeded) in having the Meteorological Service of Canada to report windchill as “feels like C” instead of, ya know, a measure of actual heat loss in Watts / M^2 / s
You say that like it’s a bad thing? I prefer not to dust off my slide rule everytime I want to know how cold it is out.
The first time they did the feels like scale… My father’s colleagues were involved. They took a sample of people and put them in wind tunnels and sprayed them with water and said hey how’s it going over there.
I wish more than anything I was joking right now.
Yeah, just give me actual temp and wind speed, and I’ll get a feel for what’s cold by going outside.
I think you are greatly overestimating the basic functional knowledge of the general public…
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.
So I’m just wondering if this is really any new information for anyone.
It’s never wise to underestimate most people’s ignorance.
Also check out his other video on his Connextras channel where he basically suggests dismantling capitalism.
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.
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In here absolutely everyone knows this stuff and it’s all just common knowledge.
Absolutely not. Not even close.
He’s making a point about instantaneous versus overall energy use, which it sounds like you already understand. “Power” and “energy” are kind of loose terms IMO, which could confuse that conversation a bit.
But for anyone still scratching their head:
The typical energy consumer need only consider watts (w, kw) when accounting for circuit capacity. For example, if your hair dryer pulls 1600 watts, don’t use it on a 1500 watt outlet, or you will likely trip the circuit breaker.
Otherwise “watt-hours” (wh, kwh) is likely the metric you’re looking for when considering energy use. This is a certain amount of power drawn over a period of time, where 1 watt over 1000 hours and 1000 watts over 1 hour are both equal to 1 kilowatt-hour (kwh), which is the standard unit you likely see in your electric bill.
It’s why low but constant power draw can significantly impact energy use. For example, a typical laptop pulls fewer than 100 watts, lower than many appliances in your house, but if it draws that much power all the time, it might significantly impact your electric bill. Conversely, an electric kettle / coffee maker might pull as much as 1300 watts while in use, more than most appliances in your house, yet it probably represents a minuscule portion of your electric bill, since it only runs long enough to boil a small amount of water with each use.
Edit: include tea drinkers, add more concrete examples
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
New Technology connections video drops:
I’m going to go buy a kill-a-watt.
I moved into a tiny home and got one for measuring the current draw of my kitchen appliances and keeping track of the cost of my electric space heater ($40/month so far, yeesh)
I’m over here heating water in a kettle because of Technology Connections (and also pre-heating my dishwasher)
Its the midwest pragmatism that sells it.
I just do what he says because it sounds so practical.
Do it, it teaches you things.
Most of your power isn’t going where you think.
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.
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).
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?
Yup.
I totally understand electricity because it’s pretty intuitive. Everything is advertised in watts, my bill comes as kilowatt hours, so it’s pretty easy to calculate how much energy something uses by plugging in a kill-a-watt and measuring it.
My gas is billed in therms. I don’t really know what that is, nor do I know what the flow rate is for my furnace or gas stove, so I have no concept for how much energy I’m using. I don’t have an electric one to compare with, so I that’s not an option either. So how exactly would I get to the point where I would be able to compare the two without a lot of annoying testing? Even then it would be extremely imprecise.
And no, it’s not “watt hours coming out of the grid,” except in the pedantic sense that they can be converted. They come from very different sources, so it’s like comparing an EV to a horse, and while you could, it’s completely nonsensical.
But yes, at some base level your average American knows there’s a connection between the two (after all, I can choose between electric heat/heat pump and a gas furnace), but they’d rely on an expert to estimate the monthly price difference between options, since that’s ultimately what we care about. The problem is mentioned near the end of the video, HVAC experts don’t seem that familiar w/ heat pumps, so you may not get a decent estimate, depending on who your technician is. And that adds to the misinformation.
lot of people from the US 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
Right, because for most people gas is metered and sold by the CCF, and not converted into kW at any point in the chain.
So I know i used 30ccf last month, but there’s zero indication what that is in kW, because we usually don’t convert between the meter (which is volumetric) and the billing, which could be anything but why bother?
Also from Europe, gas is measured/billed in kWh here as well.
Not everywhere, in Lithuania they charge per m³.
Reticulated gas is charged by the kWh here in New Zealand. The meter may well be calibrated in m³ (I don’t have gas at home, so I don’t know for sure) but all pricing is energy, not volume.
For bonus points, if instead you buy your gas in cylinders - a pair of 45kg (~100lb) cylinders is a common installation for houses without piped gas - those are sold simply by the unit. The best conversion for that I can find is one energy retailer describing one 45kg cylinder as 2200MJ (611kWh).
I expect this is one of those things that is overall horribly inconsistent depending on where you live.