AC is by multiple times the most energy efficient way to heat or cool a space and can reach 400-500% efficiency (because it moves heat around rather than generating it).
A passively cooled home, architected to prevent heat buildup in the first place (especially considering neighborhood-scale solutions like tree canopy) can take zero watts of electric power to cool. I guess if you take the architecture as given, and look only at options that consume electricity, then yes there isn’t much juice to squeeze on A/C technology. There are still some options like whole-home fans which gently suck the hot air upward.
But if A/C is avoided, then you aren’t inputting extra heat into the system to run the A/C, avoiding the local heat increase. Remember if everyone is pumping heat out of their homes, that heat ends up immediately outside the homes and into the street.
The architecture is a given (in the UK at least), since we’re not building new houses at a rate that matters, and I doubt many councils can afford to make adaptation a priority. But yeah, even if it isn’t as good, some of the principle ideas can be retrofitted onto old UK stock - awnings are easy (and on the older houses may have been there a hundred years ago!), shutters aren’t that hard, air circulation can be planned, theoretically even recolouring roof tiles or adding a solar cope cage would help. They’re certainly worth trying, though landlords can and will tell you to fuck off, and even Planning Permission might butt in if their aesthetic sensibilities are offended.
Portable AC units (plus fans, because the combo is much more efficient) have the bonus of not stepping on toes, though the ones we sell in the UK are stupid and removed the outside-intake hose - which causes a large functional problem (it draws in uncontained warm air, rather defeating the point) unless you DIY a new one on.
…hm, uh, all of which is a long winded way of saying “you’re right, but the UK is damned”.
Yes, it very effectively moves the heat into the surrounding area, and in more densely populated areas can raise temps by around 4 degrees.
Do you think the people currently installing aircon in the UK will only run it when temps reach extreme/dangerous levels, or will they develop the habit of using it at cooler temperatures - which they previously could have endured with minimal discomfort; or could have handled with more passive measures like insulation, shutters, awnings, tree cover etc. How does that efficiency compare?
I’m not saying that AC isn’t something that some people/households in the UK legitimately require, but for the vast majority this has not been the case, and may not be the case for some years yet.
This “we might not need it for some years” attitude is literally going to get people killed. You’re on a bus careening out of control going “well now we might not need to press the brakes yet”
You go on and on about the wastefulness of AC but I promise you there are going to be points where YOU WILL DIE WITHOUT IT and you’re not going to get that fucking HVAC put in while temps are killing people lmao
Climate change is already killing people, destabilising nations, eradicating wildlife. Why is it that the only solution you can comprehend is for 30 million households to immediately adopt a ‘solution’ which the majority manifestly do not need, and would make all of the aforementioned even worse.
Do you not think those lives are worthy of consideration? Or are you suggesting that we should only think about ourselves and our own comfort and convenience - everyone-else be damned - because it really sounds like that’s what you’re saying.
I love how you keep ignoring the very idea that there may be other solutions that people can take first; that people will only use aircon to create a liveable environment, and won’t mostly use it simply to make a more comfortable environment - skipping over more responsible options; and that we can all burn energy without a care for the effects in those around us and the rest of the world.
Yeah people have a lot of outdated notions about AC, I think? We’ve had temps in the 40s and leaving the AC on 28 all day uses very little energy tbh. And for heating it’s not as pleasant as radiators but it’s cheaper than gas — and will likely be much cheaper this coming winter!
In Europe, most buildings are relatively well insulated and use materials with a high thermal mass. So the building itself can soak up a lot of heat during the day and radiate it out during the night. In North America you see a lot cheaper construction out of lumber and drywall instead of brick and cement, and with modest insulation.
In North America, a brief heat wave is immediately noticed and requires a lot of work by the A/C system. In Europe, you can tolerate a heat wave lasting up to a couple days. But weeks on end? Your buildings will heat-soak and at that point it starts to work against you. Your air conditioning will run all day and all night because now the insulation and thermal mass is acting like an oven, keeping the interior warmer than the outside.
Thermodynamics has not changed in recent years. There has not been any change to the fundamentals about A/C generally taking a lot of energy to run. It is just slightly complicated because of the need to factor in the building and neighborhood in which the A/C is operating.
Thermodynamics has not changed in recent years. There has not been any change to the fundamentals about A/C generally taking a lot of energy to run.
You could as early argue that cars couldn’t possibly be more fuel efficient than they used to be because the underlying physics haven’t changed.
The main thing that has changed is the incentives, as customers demand better efficiency and (in EU at least) regulations have got much more exacting. This has incentivized refinements in design such as variable speed, better refrigerants, better mechanical parts etc, meaning that an AC unit you buy today will be significantly more energy efficient than the equivalent unit from ten years ago. It’s just a fact. They demonstrably use less energy for the same cooling.
Heat pumps are a lot closer to theoretical efficiency limits than cars. Most of the gain for cars has to do with aerodynamics and energy storage / regenerative braking. The engine itself, only modest gains. Even the most efficient ICE engines are like 45% or something, or looked another way, 55% effective at producing heat.
Variable speed and 2 stage systems do provide gain. However those are still expensive and complicated. I’m skeptical that someone using A/C for max 2 months per year will break even versus a conventional system. Could be true for common residential buildings, not so much for detached homes.
Regardless of theoretical efficiency, the problem is more “supply side”, how much heat is getting into your building. The most effective way to save energy is to reduce the heat you have to reject in the first place. Reflective roof tiles, low emissivity windows, a dang tree. Each of those could be measured in terms of heat reduction but don’t have an efficiency rating directly comparable to a heat pump because they operate passively. The social-political question is whether to move in a one-way direction toward A/C dependence or if these other options can be used instead in more temperate countries.
Ok fair enough. I think we need both in a lot of places though, and the number of places where we need both is only going to increase. And there’s an obvious synergy between the two.
Where I live we have very very hot summers (along with most of the measures you mention) and winters that rarely get below freezing, but we spend so much more on heating than we do on A/C. Yet there never seems to be discourse about people in cooler climates turning on the heating in winter.
That’s true about the double standard. It’s not great to use a bunch of carbon based energy to heat in the winter. I guess what makes cooling more conspicuous is that it’s a positive feedback loop. The waste heat makes the problem worse. Not to mention other issues like one person using (portable) A/C causing humid air to be sucked into the building, making everyone else less comfortable. But ideally, we would at least use clean energy for heating rather than carbon based fuels.
Yeah I’m beginning to realize that, like most online debates, the whole thing is skewed by Americans doing everything in the dumbest way possible. We have a well-insulated flat with integrated AC and I don’t feel particularly guilty about using it to keep temps below 30 during the summer. Especially as the electricity here is 80% wind/solar. You do get some chuds here blasting the AC at 23 degrees out of spite, but most people just want to keep their bills down without melting.
I’ve ‘lived’ in this heat without AC and it’s only possible if you accept that you can’t move or wear clothes or work or sleep. It sucked. Lots of people have no choice but to live in such conditions, and they shouldn’t have to
AC is by multiple times the most energy efficient way to heat or cool a space and can reach 400-500% efficiency (because it moves heat around rather than generating it).
What are you comparing it to?
A passively cooled home, architected to prevent heat buildup in the first place (especially considering neighborhood-scale solutions like tree canopy) can take zero watts of electric power to cool. I guess if you take the architecture as given, and look only at options that consume electricity, then yes there isn’t much juice to squeeze on A/C technology. There are still some options like whole-home fans which gently suck the hot air upward.
But if A/C is avoided, then you aren’t inputting extra heat into the system to run the A/C, avoiding the local heat increase. Remember if everyone is pumping heat out of their homes, that heat ends up immediately outside the homes and into the street.
The architecture is a given (in the UK at least), since we’re not building new houses at a rate that matters, and I doubt many councils can afford to make adaptation a priority. But yeah, even if it isn’t as good, some of the principle ideas can be retrofitted onto old UK stock - awnings are easy (and on the older houses may have been there a hundred years ago!), shutters aren’t that hard, air circulation can be planned, theoretically even recolouring roof tiles or adding a solar cope cage would help. They’re certainly worth trying, though landlords can and will tell you to fuck off, and even Planning Permission might butt in if their aesthetic sensibilities are offended.
Portable AC units (plus fans, because the combo is much more efficient) have the bonus of not stepping on toes, though the ones we sell in the UK are stupid and removed the outside-intake hose - which causes a large functional problem (it draws in uncontained warm air, rather defeating the point) unless you DIY a new one on.
…hm, uh, all of which is a long winded way of saying “you’re right, but the UK is damned”.
Yes, it very effectively moves the heat into the surrounding area, and in more densely populated areas can raise temps by around 4 degrees.
Do you think the people currently installing aircon in the UK will only run it when temps reach extreme/dangerous levels, or will they develop the habit of using it at cooler temperatures - which they previously could have endured with minimal discomfort; or could have handled with more passive measures like insulation, shutters, awnings, tree cover etc. How does that efficiency compare?
I’m not saying that AC isn’t something that some people/households in the UK legitimately require, but for the vast majority this has not been the case, and may not be the case for some years yet.
The point of everything i’m saying is PREPARE NOW
This “we might not need it for some years” attitude is literally going to get people killed. You’re on a bus careening out of control going “well now we might not need to press the brakes yet”
You go on and on about the wastefulness of AC but I promise you there are going to be points where YOU WILL DIE WITHOUT IT and you’re not going to get that fucking HVAC put in while temps are killing people lmao
Climate change is already killing people, destabilising nations, eradicating wildlife. Why is it that the only solution you can comprehend is for 30 million households to immediately adopt a ‘solution’ which the majority manifestly do not need, and would make all of the aforementioned even worse.
Do you not think those lives are worthy of consideration? Or are you suggesting that we should only think about ourselves and our own comfort and convenience - everyone-else be damned - because it really sounds like that’s what you’re saying.
i love that you keep putting solution in quotations because you really do think a livable environment is a luxury
I love how you keep ignoring the very idea that there may be other solutions that people can take first; that people will only use aircon to create a liveable environment, and won’t mostly use it simply to make a more comfortable environment - skipping over more responsible options; and that we can all burn energy without a care for the effects in those around us and the rest of the world.
What a delightful little bubble of naivety!
Yeah people have a lot of outdated notions about AC, I think? We’ve had temps in the 40s and leaving the AC on 28 all day uses very little energy tbh. And for heating it’s not as pleasant as radiators but it’s cheaper than gas — and will likely be much cheaper this coming winter!
In Europe, most buildings are relatively well insulated and use materials with a high thermal mass. So the building itself can soak up a lot of heat during the day and radiate it out during the night. In North America you see a lot cheaper construction out of lumber and drywall instead of brick and cement, and with modest insulation.
In North America, a brief heat wave is immediately noticed and requires a lot of work by the A/C system. In Europe, you can tolerate a heat wave lasting up to a couple days. But weeks on end? Your buildings will heat-soak and at that point it starts to work against you. Your air conditioning will run all day and all night because now the insulation and thermal mass is acting like an oven, keeping the interior warmer than the outside.
Thermodynamics has not changed in recent years. There has not been any change to the fundamentals about A/C generally taking a lot of energy to run. It is just slightly complicated because of the need to factor in the building and neighborhood in which the A/C is operating.
You could as early argue that cars couldn’t possibly be more fuel efficient than they used to be because the underlying physics haven’t changed.
The main thing that has changed is the incentives, as customers demand better efficiency and (in EU at least) regulations have got much more exacting. This has incentivized refinements in design such as variable speed, better refrigerants, better mechanical parts etc, meaning that an AC unit you buy today will be significantly more energy efficient than the equivalent unit from ten years ago. It’s just a fact. They demonstrably use less energy for the same cooling.
Heat pumps are a lot closer to theoretical efficiency limits than cars. Most of the gain for cars has to do with aerodynamics and energy storage / regenerative braking. The engine itself, only modest gains. Even the most efficient ICE engines are like 45% or something, or looked another way, 55% effective at producing heat.
Variable speed and 2 stage systems do provide gain. However those are still expensive and complicated. I’m skeptical that someone using A/C for max 2 months per year will break even versus a conventional system. Could be true for common residential buildings, not so much for detached homes.
Regardless of theoretical efficiency, the problem is more “supply side”, how much heat is getting into your building. The most effective way to save energy is to reduce the heat you have to reject in the first place. Reflective roof tiles, low emissivity windows, a dang tree. Each of those could be measured in terms of heat reduction but don’t have an efficiency rating directly comparable to a heat pump because they operate passively. The social-political question is whether to move in a one-way direction toward A/C dependence or if these other options can be used instead in more temperate countries.
Ok fair enough. I think we need both in a lot of places though, and the number of places where we need both is only going to increase. And there’s an obvious synergy between the two.
Where I live we have very very hot summers (along with most of the measures you mention) and winters that rarely get below freezing, but we spend so much more on heating than we do on A/C. Yet there never seems to be discourse about people in cooler climates turning on the heating in winter.
That’s true about the double standard. It’s not great to use a bunch of carbon based energy to heat in the winter. I guess what makes cooling more conspicuous is that it’s a positive feedback loop. The waste heat makes the problem worse. Not to mention other issues like one person using (portable) A/C causing humid air to be sucked into the building, making everyone else less comfortable. But ideally, we would at least use clean energy for heating rather than carbon based fuels.
Yeah I’m beginning to realize that, like most online debates, the whole thing is skewed by Americans doing everything in the dumbest way possible. We have a well-insulated flat with integrated AC and I don’t feel particularly guilty about using it to keep temps below 30 during the summer. Especially as the electricity here is 80% wind/solar. You do get some chuds here blasting the AC at 23 degrees out of spite, but most people just want to keep their bills down without melting.
I’ve ‘lived’ in this heat without AC and it’s only possible if you accept that you can’t move or wear clothes or work or sleep. It sucked. Lots of people have no choice but to live in such conditions, and they shouldn’t have to