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Comment by jacquesm | Hacker News Reader

The cruel bit here is that installing air conditioners substantially increases the per-capita carbon footprint which in turn will lead to a further greenhouse effect. It's a positive feedback loop with many components.

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Heating a house is much more expensive than cooling down a house [1], so if avg temps rise total carbon footprint due to temperature control will most likely fall. A very small silver lining to a very shitty situation.

[1] https://www.quora.com/Why-does-it-cost-more-to-heat-househol...

If I recall correctly, global "warming" is an average and changes in temperature will increase both ways so might end up having to heat more for short period of times.

Global warming is an average indeed, but moving that average for a localized area costs energy, usually in the form of carbon expenditure.

Yeah; we have our thermostat target a pretty large window. I looked at at the report for May, and it heated and cooled most days.

That doesn’t seem normal (better data now, or more fluctuations?)

That article is just saying it's cheaper to move heat than to generate it from electrical resistance. You can buy heat pumps that work both directions, allowing you to heat in the winter and cool in the summer.

My main complaint about AC and the reason we rarely use ours is that while you can heat a house very quickly, air conditioners are really only good for maintaining temperature. They have a hell of a time cooling adequately when "properly sized". So if I want to use the AC, then I have to give up on having open windows ever, which is not something I'm interested in.

I don't think AC is that bad. I have a tiny window air conditioner in my apartment. When I get home from work it's more than 80 degrees in there. After the AC has been on for an hour or two, it gets down to a reasonable 76 or so. It's in my bedroom so when I close the door to go to sleep, it gets much colder (probably 68).

I believe I read somewhere that a "properly sized" AC unit should be able to cool a home 2F / hour. I could be wrong on that, but my personal experience lines up with that pretty well.

If the weather is such that you need AC or heat, why would you have the windows open? Add humidity to the mix and open windows become even more problematic.

An oversized AC is going to run more if you have your windows open when it's hot out although with humidity may actually work better as it'll run long enough to pull out some moisture (latent cooling).

If the issue is around fresh air your average pre-2000 house breathes plenty with closed windows and newer homes tend to have active ventilation (e.g. energy recovery ventilators).

I feel like I must be missing something or you live in a warm-temperate climate such that a heat pump heats faster than it cools (heat pumps go way down in heating efficiency as it gets cold out and most work very poorly when it's much below 0°F).

The temperature generally swings something like 20F during the course of a 24 hour day. At night, I am quite content to have the windows open. During the day, I'm not around so why bother cooling the house. Then when I get home from work, it'll take the rest of the evening to cool off the house, at which point I might as well have just opened the windows and let everything cool off naturally.

Contrast that to the winter, where you can quite easily have a whole range of temperatures throughout the day based on being home or away and dropping the temp down at night while you sleep.

Heat pumps I'd guess work quite well over the same delta range that summer AC usually operates in (30F probably, even on the hottest days).

Beyond that, natural gas or propane is going to be much more cost effective.

Ah that makes more sense, thanks for helping me to understand the open windows viewpoint.

For me electricity is less expensive during the day (solar) and my house is well insulated so it takes fairly little to combat the heat gain during the day compared with letting the house heat soak through the day and then try to cool everything off in the evening. There's also often more humidity in summer so I'm trying to dehumidify at the same time and an adjusting AC (e.g. variable refrigerant flow or just a variable speed on the compressor) can run at lower consumption for longer to meet both needs at once.

I hope that Europe doesn't ever reach the same level of insanity with regards to air-conditioning that you see in, for example, Florida. The last time I visited (admittedly 20 years ago) I remember having to walk outside of shopping malls / supermarkets for a few minutes to warm up, having been subjected to the frigid level of AC inside.

That’s something that can be solved by law.

Been to Texas in summer last year (it was very hot outside) and I found it ridiculous how low the temperature inside was: most Europeans on the conference were complaining, we had to wear light jackets inside.

Then, I went to India (also in the summer): it's even worst (even colder inside and in the taxis).

These kind of things just to above my cultural sense of logic...

I think a big part of the "all kids do is play inside" thing people like to complain about has to do with everyone having their AC on all the time. If its hot inside and hot outside, you go play outside. If its hot outside and cool inside, you sit on your ass and look at a screen.

Not only that. It also increases ambient temperatures, which adds to the local heat amplification already occurring in big cities due to dense concrete buildings and streets.

one saving grace is that if you couple AC with photovoltaics, you provide at least some of that power at the point of use. not much and the upfront cost is still high, but at least it's an option.

Maybe. If the average winter temperatures go up, the air conditioning will be at least partially offset by lower heating costs. Of course, there are also theories of global climate change where both the high and low extremes will increase, in which case there's a double-whammy effect.

Average winter temperatures could well go down and average summer temperatures could go up. There is no hard coupling between the two with some fixed delta, rather that extremes can get more extreme.

Well but that would stand in conflict with the greenhouse-effect, or does the C02 go away in winters?

The greenhouse effect requires sunlight to work. In the winters, the poles do not get any sunlight. The cold air from the poles will travel to make other places colder.

The greenhouse effect does not require sunlight to work. What matters is how much of the energy radiated from the surface of the earth reaches space and how much is reflected back down. https://en.wikipedia.org/wiki/Greenhouse_effect

This is true, but what with sunlight being by far the largest factor in energy being radiated back from the surface of the earth you can safely conclude that in practice the greenhouse effect is to a large extent resulting in solar incident radiation being trapped. In other words: without sunlight nobody would be worrying about the greenhouse effect. In fact, without sunshine we'd love the greenhouse effect, reducing the albedo of the planet as a whole would be the only way to survive as a species (likely we'd fail).

An easier way to understand this whole climate debate as 'a rise in temperature means there is more energy available in the atmosphere'. That energy can have many effects. It can cause local heating, but it can also move large airmasses around and if those airmasses are colder than the normal for that region the movement will cause a huge swing in temperature.

This is one of the main reasons the average 2.5 degree celsius change (which on an absolute scale would not make a huge difference in the first place, most people would hardly notice) is such a huge affair.

It can cause local variations that are a very large multiple of the 2.5 degrees, much like a heatpump does not require a whole lot of energy to move a much larger amount of energy around.

This is, in my humble opinion, the most important aspect to climate change.

Our entire civilization is built on the assumption/requirement that there are enough areas of land that will remain within certain atmospheric parameters for enough contiguous months to grow a lot of food. Technology has widened the atmospheric parameters a bit, and has increased the yield enormously.

Climate change is the result of more energy in the biosphere. This energy is in the process of increasing the (effective) random variabilities of all atmospheric parameters, globally.

Our atmosphere has always been a chaotic system, and when the necessary parameters weren't met for a given region for enough time, then a lot of people migrated and starved.

Adding more energy into a chaotic system tends to make it even more chaotic.

As you noted, these permutations go in both directions.

More unusual heat waves.

More unusual cold waves.

More unusual droughts.

More unusual rain/flooding.

More unusual storms, both warm and cold.

And all of these things globally.

I think there's non-trivial chance that climate change will, on average, cut world-wide food production by a substantial amount over the next two decades. If that is indeed the case, it will be a lot of downs and ups, just as we're seeing now, but, slowly, more and more severe.

You'd need extreme temperatures for both, though. Remember that much of Europe is close to the sea, that buffers both in winter and in summer. Continental climate doesn't really begin until you hit Eastern Europe.

For the last few years, we've had pretty mild winters. This last one, I didn't use my radiators at all because the house is very well insulated and the temperatures didn't drop that low.

Well, air-conditioning is the one electric consumption which can be perfectly driven by solar energy. Solar production capacity is expanded constantly and in Germany we are already at the level where during sunny days, solar can drive like 40% of the grid.

Carbon is obviously a problem longer term but immediately, air conditioners generate heat.

A city full of air conditioners is that much hotter. We're ploughing energy (even renewable) into the air and that's making summer that much hotter. We need to stop.

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