Solarpunk

Dig and dont stop digging. Make a burrow

There is no alternative in hot, humid regions (cryopaint is not proven). In dry ones swamp cooling and fans help.

However, I'm not sure many people are saying air conditioning is a solution to climate change.

Many are saying it's an adaptation necessary to survive in warming humid regions. The human body cannot thermoregulate in wet bulb temperatures above 35c. Fans don't help as the body cannot evaporate sweat into saturated air that is as warm or warmer. Air conditioning not only cools, but removes humidity.

If you get a severe case of influenza, it comes with a fever. The fever is a symptom, not the underlying cause of the illness, but it can kill faster. As a result, you need to treat it as well as the flu, often with acetaminophen. Air conditioning does not treat the underlying cause, but it can mitigate the symptom that kills fastest.

Urban planning wise: I think ivy walls, or other greenery covering residential buildings.

For reference, you might want to look up Bosco Verticale in Italy, or lush green roofs in Norway.

I know this isn't a catch-all solution, but it could help mitigate climate crisis impact in addition to other options people offered here.

Some ancient middle-eastern architecture (can't remember the name) is a low-tech and permanent air-conditioning tower. We gotta go low tech. We also need trees everywhere, white buidlings and roofs, rain water collectors, etc etc.

Oh, I just remembered this video I watched. There is this guy on youtube that does a lot of material-sciency kind of stuff using common household ingredients. One of his videos he makes a salt-based phase change material, which basically works as an icepack that freezes at around 18 degrees Celsius.

The idea is that it takes a long time for the material to melt from 18 degrees to 19 degrees so it can keep you comfortably cool if you put it in a plastic bag and wear it in a vest to keep yourself cool. If you have a cool basement, then it can pretty much re-freeze by putting it on the cold floor.

DIY Supermaterial Could Save You From Heatstroke: Salt based PCMs

Its an interesting watch.

If you can come up with an alternative way to cool the air indoors that’s less energy demanding and environmentally friendly that could be a revolutionary invention on a global scale

Not gonna debate A/Cs merits as a fix for climate change but the ability to chill and cool a place at will is one of the overall more important human innovations ever. Food storage and preservation as well as tons of medical/scientific research and development is dependent on refrigeration.

It’s also really gonna depend on where you live in the world to be able to rely on standard fans, which still rely on electricity and if the humidity gets too high for your sweat to evaporate may not even cool you down properly enough to prevent wet bulb heat deaths. Bangladesh for example will cook in the coming years without something to break the heat and muggy air.

@turip youtu.be/AAz5D3TnQ_k This video lists basically every option you can have. I posted it already, but building a city to create air corridors and using water-porous asphalt when you have to have it, which allows for evaporative cooling during the summer, as well as using ponds and water to create a cool island effect, can significantly reduce heating.

The best you can do quickly and for free is to close blinds to let a small amount of light in when its hot, and when it's below 20°, open windows and have as much ventilation as possible. This is easiest and I find that in some rooms it can cool them significantly.

If you are looking for passive alternatives, then I've got bad news: you have to design them before you build a house.

In Iran, before electrical power became available, they used wind towers to draw up ground-cooled air through the qanat (underground aqueduct) system. It works without external power, but you have to know you need it before you build houses.

Also, simply a house with very thick stone walls (expensive to build), a cellar (possibly with a cistern) and no south-facing windows will stay cool during summer peaks.

The alternative is architecture designed to keep a building cool.

Heat pumps. Work as heating and cooling, far more energy efficient

Most solutions require engineering the building for little to no use of AC and relying on better ventilation.

One example that can be applied to a house is a central shaft with a fan on the bottom, which will pull in air closer to the ground and blow it upwards - remember, cold air tends to stay down while hot air tends to go upwards. The house will need to have a small elevation, or the central shaft will need some ducts for the air to come in.

There's also the Persian Windcatchers, which they have used for centuries, towers that receive hot air from one side, bring it down to an underground channel and blow off cold air from another side.

There's plenty we can do, but all interventions are somewhat limited in effect. With the trend of increasingly intense heat waves, we're likely going to have to do all of the non-AC interventions and install AC in lots and lots of places.

• Awnings to block sunlight from heating up spaces through windows
• Better ventilation systems which can more effectively pump in colder air from outside during the night
• Heat-reflecting paint to minimize heat gain from solar radiation
• More trees to provide local cooling/shade
• Ceiling fans to provide reduced perceived heat
• District cooling, when appropriate, to provide cooling at a higher energy efficiency

All help, but when the temperatures start hitting 40 C with high humidity, you're basically out of luck without an AC, that can pump out the heat and lower the humidity.

I'll answer your question first, but I have some issues with the framing you're using around that question. The two other main methods of practical temperature management available to us are evaporative cooling and geothermal. Your body has a built-in evaporative cooling mechanism called sweat. Fans take advantage of this. But not everyone has equally effective bodies for this, not all climates are particularly effective for it (high humidity makes it extremely ineffective) and not everyone finds it comfortable for their situation. Swamp coolers are a different form of evaporative cooling that move the evaporation process onto a substrate which then cools things down with a fan. You can also find natural evaporative cooling working for you in many places, for example around large bodies of water. There is an externalized cost here if you're trying to make evaporative cooling work in an environment that's unsuitable for it, and the cost of fresh water is a significant line item on the energy budget too. Don't neglect that by assuming evaporative cooling is a clear win that is automatically preferable to an air conditioner. All these evaporative solutions share the reality that they're going to add (often very significant amounts of) humidity to the air. Air conditioning on the other hand can actually remove humidity from the air, and is one of the few practical methods of doing that. It's solving the issue in a different way, but it's a significant and important difference.

The other option is geothermal. This is genuinely underutilized today and I think we can certainly save a lot of energy budget by accessing stable and susprisingly comfortable temperatures underground basically year-round. Geothermal heat pumps (which use air conditioning technology) are by far the most practical way of doing this in our current situation, but older solutions involving buildings that are deeper in the ground or that have airflow going through the ground can provide access to this temperature too -- with the caveat that you'll often run into problems with water, flooding, or condensation/mold unless you're in a particular sort of environment where this is not a concern.

As for the framing: You have to look at it systemically I think. We do a lot of things that seem dumb on the surface, and sometimes they are dumb, but more often they are making tradeoffs for particular reasons and a lot of times those turn out to be the right tradeoffs, there's just a lot of complexity to the system that you're glossing over. You can certainly argue those reasons, and try a different path, as long as you understand them first. Some of the reasons might be invalid or the tradeoff might not be the right trade, but I don't see the benefit in making blanket value judgements without understanding what they are and why they're happening. But I think you'll find it more challenging than it seems to come up with a better solution in the long run.

What is your specific objection to air conditioners? Temperature is a huge line item on any energy budget, and it has to be managed somehow. There are few places on the planet where humans can live year-round without some form of temperature management, and quite often that requires energy. Firewood is not always a given and not perfectly sustainable at least the way we use it. An air conditioner is not propaganda it is a tool, and you have to figure out if it's the right tool for the job but that's never going to be a binary true/false. I think saying you're "completely opposed" to them and calling them propaganda might be blinding yourself to what the actual goal is and what tools you can use to get there.

Using an air conditioner to live in a hot place is, at least as I understand it, still more energy efficient than using any kind of heater or even a heat pump (which is just an air conditioner in reverse) to live in a cold place, and hot places also have more readily available sources of other energy, typically, so this is not necessarily the wrong choice as transmitting energy long distances is not always a good call either. But you have to understand the tradeoffs you are making. This is why it might seem like propaganda, but it might just be that someone's done the math and come out to this answer. If you are looking at different numbers, or missing some of those numbers, you might come to a different conclusion, but the air conditioner itself is not the problem, the disagreement in the numbers and the context you are putting those numbers is going to be the root cause you need to figure out.

An Awning: https://www.youtube.com/watch?v=uhbDfi7Ee7k

Back to the caves. Literally.

Extremely good insulation, possibly building things underground, and then air conditioning. You said people with health issues. If you need to make sure something is a a specific temperature because of health concerns, you need air conditioning to be certain. Really making sure you've got incredible insulation is really all you can do. Tall trees that block the sun around the building can help. Using blinds and curtains as well instead of letting the sun in.

I think they are a viable solution, as long the energy comes from renewable energies. Where I live, the time you need cooling, ist also the time when energy prices almost go negative. If wind turbines are switched off, because the energy cannot be consumed, I think using them for moderate cooling is ok.