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
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