# What is the hottest temperature humans can comfortably live in (or survive) with technology

Assume you have all the tech available to you indoors. Air conditioning, insulation, fans pointed at you, etc.

What is the highest temp outside a person can comfortably live in? What about survive?

Example: if it is 65C outside but you are inside an insulated home with AC on and a fan pointed at you, can you feel comfortable or is the temp outside so high that AC and a fan can’t cool you off enough?

What about 100C? Where is the point where no matter how much AC, insulation and fans you have you still aren’t comfortable at best, or can’t survive at worst? Wouldn’t all the water boiling at 100C cause AC to stop working and make sweating useless at best (even if indoor temps were lower than 100C)?

All the AC in the world isn’t going to help if it is 500C outside. But I have no idea what the actual cutoff is, I’m assuming it is somewhere around 80C but I have no idea.

What about inside a car, is a car with the AC blasting comfortable when it is 60C? I know earth’s temperatures tend to top out at about 58C, so I don’t know if it would matter if AC still worked fine in 80C temps, because those do not occur on earth.

I don’t know the math of insulation or AC, but if you assume 21C is ideal temperature, humans can survive perfectly fine indoors when it is -73C, which is pretty far away from ideal. Does the same apply in the opposite direction or because AC and heating use different technologies, you can’t compare them?

Electrical wiring into a house is commonly rated for up to 60º-75ºC. So a temp of 100º would be causing problems with the electricity to power your AC, fans, etc.

Huh? “Rated at” for all and every efficiency air conditioner/freezer combination that non-industrial-rated housing can cram not a circuit?

The Apollo lunar missions saw astronauts and equipment operate at near 200C. IIRC, Earth orbit also sees some pretty high temperatures when exposed to the sun.

I suspect the answer is, pretty much anything in theory. Probably limited bu economic and technical issues.

I have mentioned the early astronauts’ training before, but I tried to find a cite and failed. But, I distinctly recall testing to determine such limits. There is a photo of an astronaut sitting in an ‘oven’ with a loose foil mask draped over his face to protect the eyes and lips. They tested up to 350F as I recall. And not just in and out, but sitting there for 15, 20 minutes. Your sweat keeps you from cooking for a short while.

Dennis

You could go to Dallol, Ethiopia and see what it is like. This place, located 430 feet below sea level, has the highest year round temperatures on earth, around 95 degrees F.

From the looks of the place, not much A/C around.

I don’t think that this question is really answerable in a definite sense.

But if you had a few metric boatloads of money, you could build a house with several distinct zones, from outside to inside, with each zone being a certain temperature cooler than the zone beside it. The AC for each zone would dump its heat into the next zone outward.

Such a system, combined with really efficient insulation, would allow you to survive much higher temperatures than earth normally sees.

Are we limited to off-the-shelf technology here, or can we make a one-off job? And how long does it have to be sustained for?

Assuming that a custom build is allowed, I suspect that you don’t hit a limit until the air conditioner parts start literally melting.

The Apollo space capsules endured 5,000 F when reentering earth’s atmosphere from a lunar trajectory: Apollo's Re-entry | HowStuffWorks

NASA’s Solar Probe Plus will approach the sun 1/8 of Mercury’s closest orbit: Parker Solar Probe - Wikipedia

It will withstand over 2,500 F, however it is better expressed as endured energy flux from the sun.

According to this calculator, the solar flux at that distance is 831 gigawatts per square meter: Solar Radiation in Space | PVEducation

Despite this the spacecraft payload will be at room temperature. Given enough funding it seems technically plausible a human could also survive (from a temperature standpoint):

http://solarprobe.jhuapl.edu/funFacts.php

Is there a missed decimal point somewhere there? It looks like it will approach to about 6 million kilometers, which would be 6*10[sup]9[/sup] meters, right? So I plugged that into the calculator, and it gave me 803944.44 watts per square meter, or about 800 kilowatts per square meter. Did I make a mistake somewhere?

Yes thanks for that correction. Yes, it is around 800 kilowatts per square meter. That is still a lot – roughly the same energy flux as the Boeing ABL, which output 1 megawatt in 1.5 square meters. It would be like a group of these simultaneously blanketing the vehicle surface, continuously: