Food Autonomy w/ Evan Doukas: How To Build A Climate Battery Greenhouse


In today’s episode i will be doing an in-depth “how to” episode with my homey Evan Doukas from Colorado.  Evan is a preacher, a permaculturist, a father, a musician and also publishes homesteading/permaculture videos through his youtube channel, The Colorado Garden.  In this episode Evan breaks down how to build a “Climate Battery Greenhouse” step-by-step.  A climate battery greenhouse uses the heat from the earth to grow fruits and veggies from tropical & Mediterranean regions in temperate climates.  For more information check out Evan’s youtube page documenting his work with his.  For more background info on these check out this prior Solecast with Stephanie Syson from Colorado Rocky Mountain Permaculture Institute.  

Evan was kind enough to pass on his notes that he used to source for specific materials and data for building his greenhouse. We’ll include them here so you can check them out, and hopefully they will be of use to you as well:

My greenhouse is approx 14'x11'x9'

=1386 ft3 (cu ft)

Using the formulas given by Sunny John, i estimated that I needed approx 225 linear ft of subterranean tubing.

So, take 15-20 percent of the cu ft number, and that is how many feet of tubing you ideally want underground.

*Note, all tubing lengths used should be equal in length to ensure an even amount of airflow..

In my greenhouse there is an approximate total of (only) 120 linear ft of tubing.

The tubing is in 3 flat rows of 4 10-ft lengths that are spaced approximately 12 inches apart on all sides.

In regards to air movement, you want to move a minimum of 128 cubic feet per minute (CFM) with my 1386 ft3 greenhouse.      

So, take approx. 10 percent (or a little less) of the cu ft number, and that is the CFM fan you want to use.

The fan I used is an (8”) corded in-line air duct booster fan by Suncourt with a Suncourt variable speed controller ($45) ($30)

I used 8” galvanized ductwork ($50)

For plenums I used taped buckets, but I did it again for a similar room I would use 55-gallon plastic drums on either end. (free to $150)

2 Thermostats (1 for low temperature threshold and 1 for high temperature threshold), used something like: “JOHNSON CONTROLS

Line Volt Mechanical Tstat for Heating and Cooling, 120 to 277VAC” (cheaper then but now $210 for 2)

Roofing top layer: Used 9 Sequentia Super 600 Residential Fiberglass Panels ($325)

For underground tubing: 4” corrugated and perforated ADS pipe ($150 for 200 linear ft)

*Drain sleeve optional – did not use

(WHOLE GREENHOUSE WAS BUILT FOR APPROX $875 + Lumber = No more than $2K total)


Subterranean heating items:

8” (x 60”) duct -

And a 24” for a little added height if needed -

8” elbow/end -

8” inline fan -

Variable speed controller for fan -

ADS Pipe (Lowe’s cheapest – 100ft):

ADS connectors:

Snap-in ends to screen?: SHOULDN’T NEED

Drain sleeve (100ft):SHOULDN’T NEED

Possible solutions for thermostat: (call them)

Sunny John recommends this (don’t know how it works):

Steel 55 gallon drums (Lafayette - $10 ea):

and *****

Mathematics of layout:

Approx 225 linear ft of tubing

Approx 128 minimum CFM fan

Excellent greenhouses

A great example showing a clever design with reflective panels concentrating the winter sunlight into an above ground pond to heat the greenhouse at night.

and more from the same manuf., as well as solar “central air” system:

CO supplier of Lexan and acrylic

Underground greenhouse and heating

The good heavy duty corrugated fiberglass panels are Super 600. and others

Solar cooling and heating system, everything needed $3,450:

Corrugated (Perforated) irrigation tube

Christmas lights (i.e. 25 Bulb C9 Incandescent Transparent Light Set – Clear)

Tubular heaters? Find out wattage

Lean to recycled greenhouse with outline of process:

Subterranean Heating:



Overhead plans

Calculated that 112 cfm or a little over 100 cfm is needed. Verify again before purchasing fan but here is link for appropriately powered fans:


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