How to Make Cheap Air Conditioning Earth Tubes
Yes, there is a way to make your own air conditioning cheap and easy–they are called earth tubes, or simply “earthtubes”
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These in-ground PVC cooling tubes are also known as air tubes, earth air tubes, a ground-coupled heat exchanger, an earth-air heat exchanger, thermal labyrinth, heat recovery ventilation, geothermal energy tubes, sustainability tubes, or a number of other terms. Earthtubes are an efficient way to cool or help heat your house in winter using natural cooling principles. They require no pumps or fans, and are completely passive (no moving parts).
This also means no electricity bill to “run” them, saving the building costs for the lifetime of the building, which keeps money in your pocket, and keeps your carbon footprint down. This is both natural cooling, and green cooling, simultaneously, and the principles take advantage of what nature already knows how to do.
Running the A/C (air conditioning) unit in a standard electric HVAC-based house can costs up to hundreds of dollars per month, especially in homes that are not insulated well. What a waste of money, yet who wants to deal with the summer heat! Earthtubes may be your solution as their payback time is minimal.
Earth tubes work by harnessing what nature provides us naturally, but just utilize simple principles and allow us to cool the ambient air temperature by usually at least 10 or up to 20 degrees Fahrenheit, depending on your home’s energy efficiency values.
These earthtubes work fantastic in humid climates, although they work in arid climates as well. While outside it is 98 degrees F, inside can be a cool 78 degrees! When I built my passive solar straw bale house, which utilized several earth tubes as its sole inexpensive “air conditioner,” it was 99 degrees outside in summer with 99% humidity, yet inside it was a cool 70 degrees due to the R-50 insulated walls!
The cost for making these earthtubes is minimal, perhaps several hundred dollars at the most for the entire average-sized house (approx. 1000-1500 sq. ft.). Larger houses just utilize more earthtubes.
Since they last for the lifetime of the house (some have been going for 25+ years without any problems, and mine were constructed in the late 1990’s and are still in use today), and use no electricity, they can replace, or nearly replace any evaporative cooler (swamp cooler or Mastercool) or full size air conditioning unit (or several window air conditioners), depending on the house, location, and efficiency of the home.
History of earthtubes
Earth-air tubes are based on very old technologies from the Middle East, including ancient Persia, with similar designs that the Romans used, etc. Waterways and underground canals or qanats diverted water through a tunnel system that ran underneath buildings.
A vertical shaft was put in the lowest room of the house or building to tap into the tunnel of water, and sometimes a tower or chimney (sometimes a solar chimney) was added to the top of the house. The air would get sucked up out of the underground tunnel channel, up through the rooms in the house, and then escape out of the chimney/tower. The result was a very cool house, and a basement style room that was even quite chilly (similar to a root cellar).
Earth tube style A/C is similar in design and very simple to make, and does not require any underground water source (in fact, it creates its own water, much like a window air conditioning unit does, which drips away into a gravel pit back into the earth), and is not nearly as labor intensive as qanats or yakhchals. However, where you live and what kind of soil you have, how deep your frost line is, what type of weather you have, etc., will determine just how hard (or easy) installing your earthtubes will actually be.
Another consideration is whether you have a house you live in already that you want to add earthtubes to, or if you are planning on building a new house and would like to incorporate these into the infrastructure of the house prior to building. Both or either can be done.
Cheap home air conditioning – how earth tubes work
When 1 or 2 windows ONLY (preferably high windows) is/are opened the hot air rises and escapes out that window(s). This will create a pressure difference inside the building, causing it to suck in air from the tubes. This is the natural process of convection working in your favor and why no pumps or fans or electric motors are needed.
The air going into the tubes from the outside, over 100′ away from the floor/wall registers, cools off due to the earth’s stable and cooler temperature, causing the water to condense out of the air, bringing the cooler dryer air into the house. It is a natural slow process and moves gently as an air exchange process all day long. Inside the house there will be a 10-20+ degree drop in temperature compared to outside.
You will need about one earth tube per room, although there are methods to split off the tubes in a “Y” fashion, or even make larger tubes that break off into smaller tubes. There are even ways to make the tubes above ground and covered over with a mound of dirt, and are ideal for underground or earth bermed houses. The earth-air tubes can even be used to create water from thin air, which can be collected for use on plants and more.
There are two options if you need to learn more or how to make your own earth tubes. I have a small FREE old version (2008), or you can get my newly published book (2016, 186 pages) on earth tubes that is for sale, but also a FREE version of that is available (please see below).
For an intro, you can download my free ebook (of my many titles of ebooks for free) on How to Make Cooling and Heat Tempering Earthtubes (version 1). This e-book is FREE here as a PDF download:
Here is a much-expanded version (v2) paperback book with far more pictures and step-by-step instructions under the title:
This book, greatly expanded, is available through Amazon and Kindle. The paperback is $29 and includes:
history of where earth tubes come from (3,000-year old sustainable technology)
includes a parts list
exploded view of how a tube is built
yard layout design samples
list for planning construction of your earth tubes
ways to cover or hide the tubes
adding earth tubes to a new or existing house
interior wall and floor options
information on radon, mold, and indoor air quality
how to use the earth tubes
photos of the tubes we made when we built our house
different designs and options
solar chimneys and other supplemental designs
spiral tubes and water catchment ideas
The Kindle version costs less than the paperback, but if you have Amazon Prime or are a KindleUnlimited member then the e-book is FREE as well for you. If you prefer a hard copy (soft bound) than to read digital versions then the paperback is $29.
I also have the last chapter of my version 2 book above, called Earth Tubes Q&A available below:
Keep watch and be sure to sign up for our newsletter (right hand column near the top of this page) to be updated as to when my next free ebooks will be made available.
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