Ask HN: Possible to go/live underground to cool off? | Hacker News Reader

Ask HN: Possible to go/live underground to cool off?

I remember 40 years ago or so, underground or partially-underground houses were a thing - at least where I was occasionally in Pottsville (??), Pennsylvania.

I don't really remember why it was a thing, but I think I remember that it was because having a house underground-ish -- say, with just one face of the house exposed -- kept the house at earth temperature, which was generally a good thing -- no need to heat, nor cool. I think at the time maybe people were talking about heating bills??

If all that makes sense, could we do it again?

I always thought that it was awful to force humans underground -- like with subways -- but if it's a matter of survival...

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My house is half dug in to a hill; west TN USA. Summer cooling is a bigger concern here than winter heating; and it wins in the summer.

In the winter, it's still a minor win, the half the house with the dug in brick wall wants to be ground temperature (say 60F), which is still higher than air temperature... but its difficult to get it heated up to temps i can live with (72F).

Much thermal mass that has inertia.

Moisture and mold etc are problems even with some extreme measure against direct water incursion. We've got river rock / french drain type gravel between the house wall and actual dirt, on the buried side. That's in addition to some heavy sealant on that side of that wall. Without that, if the dirt came up to the wall; there'd be constant water seepage on the inside of the brick wall. I know, it happened; we dug the dirt back out and refilled with the river rock. fiddly backhoe work that.

in the summer that wall will collect condensation water if we let the house humidity get too high. in the spring and fall when we open windows and don't run the air conditioner that wall can be moist to the touch.

Thanks for sharing.. I love hearing how people deal with overcoming challenges in building science. There are so many unique situations, but they all simplify down to a handful of variables.

Look up "Earth ships". I have a pretty good book on them, but will have to get back to my library before I could tell you what its title is. I was researching these for awhile and honestly a lot of the reference material is going to be from the 70s. I bought a ton of books about passive solar and such and I think the vast majority were published during the oil crisis.

It's definitely a good option, but you're going to be pushing the boundaries of your local contractors and the materials you can source and or hire a crew to install. If you're motivated, there are any number of ways to construct these dwellings, but the most interesting and appealing method that I saw was one made like a commercial warehouse. It was in Virginia, maybe around Roanoke in the mountains, but the owner used steel warehouse trusses and a dexpan roof (poured concrete over a substrate like corrugated metal). Since it was a known method, he hired a commercial crew to do it and they didn't have a problem iirc other than getting the crane down his driveway. Istr I found this on the break time finehomebuilding forums...

I’ve seen a few of these. A family friend built a custom energy-efficient house in the ‘80s that is partly built into a hillside. The other main feature is automatic ventilation when exterior temperature/humidity conditions are favorable (basically just automatically opening windows using ‘80s-era home automation electronics). My guess is you don’t see more of these because the site-specific architect and engineering costs put it out reach for non-wealthy people, unless you have the skills to DIY much of it. Plus possible maintenance issues and building code and insurance hassles. Here’s a basic intro from the DoE: https://www.energy.gov/energysaver/efficient-earth-sheltered...

I recently learned of a spectacular example of this: The Forestiere Underground Gardens in Fresno:

https://en.wikipedia.org/wiki/Forestiere_Underground_Gardens

> The Forestiere Underground Gardens in Fresno, California are a series of subterranean structures built by Baldassare Forestiere, an immigrant from Sicily, over a period of 40 years from 1906 to his death in 1946.

> Baldassare dug a small cellar to escape the summer heat. He was likely influenced by Roman catacombs and wine cellars he had seen in Italy. Finding it effective and comfortable, he carved a series of attached rooms and took up residence there. Baldassare then began experimenting with growing trees in underground chambers with skylights, and found that with care they would grow well, and being below ground protected them from frost.

http://www.undergroundgardens.com/

Instead of building underground you could use earthen materials but stay above ground.

https://www.youtube.com/watch?v=IuQB3x4ZNeA

While rammed and compressed earth is great, building underground regulates temperature because the temperature a few feet underground is constant, and such a building is basically a passive geothermal heated and cooled system.

I won't be able to back this up by any form of proof, but I have talked with the R&D departement of a major construction company located in France. They have plans to try to build underground cities in the foreseeable future in order to cope with 1) overpopulation in already dense cities and 2) provide alternative solutions to living in cities that are getting warmer and warmer. They showed me pictures of what it could look like, and you can basically imagine The Line in Saudi Arabia, but underground. That was 3 years ago.

What surprised me the most was that it was something they thought would be mostly sold to the very rich. This conversation got me very depressed.

Yes but everything becomes harder if underground there is a bit of water or humidity. Think about molds and poor living conditions

It's very geology dependent, but they do this in Coober Pedy, a town in Australia where underground building is common for cooling reasons.

https://en.wikipedia.org/wiki/Coober_Pedy

I don't think it's something we will transition to in general "for survival" though. Building regulations should just catch up and enforce appropriate insulation levels and building methods for the given environments.

Also there is zero humidity there. I would imagine that would affect an underground house a lot.

Source on humidity: did a 3 month tour there as a chef - never again.

I honestly thought you meant being antisocial for a period in your life.

The answer is hell yes, either way :p

It’s hurricane o’clock presently in phoenix, and my internal organs should be cooked by dinner time. You might say that I’m therefore on board with out-of-the box ideas, like being mole people.

Versus this? Yes! Absolutely. Let’s use the cold ground for thermodynamic comfort, before it is ultimately a final destination.

I once visited Frank Lloyd Wright’s Taliesin West in the Arizona desert. It was built in the 1930s and pioneered passive energy and cooling technique’s in the desert like you mentioned [1].

While Wrights building techniques do work. There is only so much you can do. For example you don’t see anyone building caves to store wine in the desert. In Europe where you used to see cool weather the majority of the year and a scorching summer, yes it makes sense to go underground because it was naturally cooler.

In the desert, the earth itself is hot and if go underground, it will only get hotter.

[1] https://franklloydwright.org/living-with-nature-passive-ener...

> In the desert, the earth itself is hot and if go underground, it will only get hotter.

Not the case in practice ...

    It can get to be 42ºC (108 Fahrenheit) in the Australian town of Coober Pedy — and that's in the shade. With opal mines that look like giant ant hills and a network of underground dwellings where residents live, this is the kind of place where the searing heat warps perspectives, and yet somehow clarifies them. [1] (corrected, npr got the common summer max temp conversion wrong)

    The miners quickly discovered the advantages of living underground to escape the heat of the summer and winter's cool desert nights. No matter how harsh the climate, the underground rooms maintain a comfortable, even temperature ranging from 23ºC to 25ºC day and night throughout the year. [2]

[1] https://www.npr.org/2007/08/17/12873915/coober-pedy-one-of-e...

[2] https://www.cooberpedy.com/underground-living-dugouts/

It could be that “Most dugout homes are excavated into hillsides rather than dug from shafts” from your second article. AFAIK temperature doesn’t get cooler underground. https://en.wikipedia.org/wiki/Geothermal_gradient

Hi, I'm in actual geophysics .. and you're linking to a phenomenon (quick, read your own link) that occurs over a scale of tens, hundreds, and thousands of kilometers.

Near surface underground is different.

Aquifers and all manner of other things behave differently to your blanket "AFAIK temperature doesn’t get cooler underground" and it's well known in practice that digging down a few stories evens out the tempreture compared to above ground.

This even works as a cheap passive cooling system for data centers:

https://pawsey.org.au/groundwater-cooling-system/

data center was the original reason for my buried wall: the computers were going to live on that wall and shed their heat into it. Big heatsink. Worked well for a couple years and then AT&T decided to take away my bandwidth, so i had no more excuse to have 10kw of racks running.

The one by the people who flew with the geese is interesting.

https://youtu.be/RoGuvvzHY1A

Edit: I'm thinking mostly underground is much cheaper and reduces the risks of wildfire, wind, hail, tornado, and lightning. / There's also the opal miners in Australia who built their whole town underground. https://youtu.be/4h9XwwgQKRQ&t=2s

Ancient humans are thought by some researchers to have done much the same. The deep underground artworks in some French caves are said to be evidence of humans escaping the cold.

There's a reason I can think of that it might not work so well again. Lots of non-human animals survived the cold quite well, so there was game for those ancient ancestors to hunt, but there might be much less game surviving in great heat.

And having game to hunt or not, is relevant to modern citizens how?

Post-apocalyptic citizens will get hungry too, although heat death isn't the usual apocalyptic scenario.

in the northwest region of China, there has been a tradition of building 窑洞(yaodong) since ancient times. The 窑洞 are warm in winter and cool in summer, but this type of architecture depends on geological conditions. The area is located on the Loess Plateau, where the soil is sticky and rainfall is scarce. You can find many photos and videos of cave dwellings online.

> but if it's a matter of survival

What is threatening your survival that you feel you need to live underground?

Heat index in Kansas today was 135F.

> Heat index in Kansas today was 135F

Really? https://twitter.com/NWSWichita/status/1693417230661472301

They typed "Heat index" not "tempreture".

https://www.weather.gov/ama/heatindex

presumably the humidity was 40%.

Yeah I googled “Kansas heat index today” and nowhere could I find anything like 135, so was just wondering whether that wasn’t a typo.

134 according to https://twitter.com/NWSTopeka/status/1693346851427438815 (off by one errors etc)

It's a hell of a lot more practical than going to Mars...

there is a great possibility humans survived extreme climate disruptions in cave systems, and tunnel complexes.

Radon and lack of vitamin D will be problems.

Geology dependent, Radon expresses from cracks in uranium rich granites and is a smoking three packs a day equivalent problem at worse and a non issue in many places.

Living underground doesn't mean you can't swim and surf in the mornings and evenings nor stop you from piping in natural sunlight via architectural means (light wells, mirror tubes, etc).

Radon and Thoron in Kenyan earth houses, I dont know if this problem spreads to various underground railway/metro systems which are everyday and common in cities.

https://www.frontiersin.org/articles/10.3389/fpubh.2019.0011...

Vit D, can be replicated with UV-B flo tubes used by people keeping reptiles.

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