Renewable Revolution

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February 3rd, 2018 by James Ayre

SNIPPET:

Earth-sheltered homes are homes built using soil or substrate of some kind as external thermal mass to provide insulation, and various climate control properties. To put that in plain language, earth-sheltered homes use dirt, rock, and vegetation to protect the home from the elements.

Such homes can offer significant advantages over conventional approaches when it comes to reducing heating/cooling costs and needs, indoor temperature variation, and durability (ability to remain unaffected by high winds and storms).


Designs can vary quite a bit — with homes being either nearly completely encased in earth and underground (as in traditional quiggly/kekuli designs in Pacific North America); built above ground but completely encased in thick earth (like traditional Plains and Eastern Woodlands Indian “Earth Lodges”); embedded into cliffs and caves; built as wattle-and-daub homes set several feet into the ground; amongst a great many other options.

As alluded to above, earth-sheltered homes are found all over the world and likely go very, very far back in time … possibly even further than “home sapiens” do — as seems to be true of long-houses, seaworthy ships, and temporary yurt-style structures, amongst other technologies (needles/sewing, jewelry, blades of various kinds, highly specialized fishing hooks and traps, etc.).


Full article with more pictures:

https://cleantechnica.com/2018/02/03/earth-sheltered-home-plans-modern-designs-earth-lodges-prehistory-skara-brae/

Barry Alternative Fact Covfefe

The hype behind earthship homes is greater then their performance, humidity is often very high, they gravitate towards 10C (nicer then freezing winter but much cooler then humans are accustomed to even in summer), they are expensive to build, they can be very maintenance intensive (and leaky), the thermal mass sucks heat away from the home and so forth. Thats not even getting in to the Radon concerns.

Green Building Advisor has an article called "Earthship Hype and Earthship Reality" that explains the hype rather well.

agelbert > Barry Alternative Fact Covfefe

The ambient temperature of a home reliant on passive geothermal, such as the Earthship type home, is dependent on the latitude and altitude of the terrain they are built at. One cannot use broad brush criticism on this type of construction. In some places it is a good idea and in some places it is a bad idea.

In order to be truly objective in doing a cost benefit analysis of passive geothermal advantaged homes versus more conventional above ground homes, you must compare the thermal conductivity of the materials used for the structures.

For example, at an outside air temperature of 25C (77F),
earth is 1.50,
ground or soil/moist area 1.00,
ground, plaster/sand 0.71,
water 0.58,
ground or soil/dry area 0.50,
sand/dry 0.25,
plywood 0.13,
straw slab insulation 0.09,
and 0.024 for air.

Source:
https://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

The value for air is a bit misleading. The fact is that air must not be moving for that value to be of any use for insulation. Air around an above ground structure is always moving, thereby drawing heat away from the structure immersed in the air. The cost of insulating in air must be compared with the cost of insulating with other materials like straw slab with earth berming, which has such great value as insulation because it does trap air in cellulosic material.

It is true that moving earth around a home costs a lot of money. That alone jacks up the price of an "Earthship" type home above what most people can afford, as you have noted. There are other high cost issues like meeting code requirements for a home that is, like a basement, in need of a certain number of exit areas in case of fire.

However, there are potentially huge savings to the earth bermmed or buried home due to reduced insurance costs. These homes, provided they are above any flood prone areas, are virtually impervious to storms which produce high winds, torrential rain, lightning and tornados.

Global Warming will visit that type of damage to above ground homes with increasing frequency and consequent cost. So, the added security the passive geothermal advantaged homes boast will increase their popularity.

All that said, provided you build your earth bermed or buried home in an area that geothermally works to give you 61 degrees F (about 16C) year round, instead of 50F (10 C), the energy required for heating and cooling will be far less than that of a conventional above ground home, regardless of how well the above ground home insulated.