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.
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…
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
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.
In here absolutely everyone knows this stuff and it’s all just common knowledge.
Absolutely not. Not even close.
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.
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.
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.
haven’t seen it so far, but technology connections will always get an upvote.
also consider subscribing to his channel, his videos are amazing.
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.
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.
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.
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.
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?
In my highschool physics was optional. You had multiple options for science credits and could get through without taking it.
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
Follow-up video idea: speed ≠ distance
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)
