Earthship Research: Freney

Martin Freney
Earthship Ironbank. Digitally available at:

Reviewer’s Commentary:
Freney is well regarded as one of the foremost researchers in academic circles regarding earthship design, but some of the graphs on this page are disappointingly incomplete. The study could be greatly enhanced if it were to address which of the studied systems actually show correlations, especially in figure 8.157 Whole House Weighted Score. His items labeled “gas for cooking”, “miscellaneous”, “water and wastewater”, “food production”, and “gas for hot water boost” show strong relationships across the building systems, and thus can be eliminated for clarity. The only pieces of the puzzle that are relevant are the “thermal envelope”, “heating and cooling”, “household electrical”, and “waste”.

The chart compares the off-grid earthship and an off-grid adobe house against other wall types that are all on-grid. That skews the results to appear to favor the earthships when in fact they cannot be compared in this way, as off-grid build performance should be compared against other off-grid builds using various building materials, not to alternative systems in on-grid builds.

The major difference in the “household electrical” seems to be grid-tied versus non-grid tied systems. We believe that the tricks for minimizing electrical use used in earthships can easily be applied to other systems. So, for our inter-office review, we eliminated comparing the power requirements for the various systems, comparing the remaining four components - “thermal envelope”, “heating and cooling”, “household electrical”, and “waste” - to see what the graph was really saying.

Some observations:

  • ES1, the earthship that has no berm, is made with adobe, and has no greenhouse, but is insulated… is compared against uninsulated adobe. That skews the perception of the adobe’s performance, and unfairly so. At least in the US, adobe requires thermal wrap and insulation to be code compliant.
  • There is no mention of the timberframe infill or insulation. Whether the infill is an insulating system or a thermal mass type system is a relevant discussion when comparing systems. The thermal performance of the infill can range greatly, depending on the infill type.
  • We believe that for accurate comparison, the wall systems should be built on the same assumptions: the same passive solar orientation; rainwater harvesting; water and power provided by thermal solar and photovoltaics; greenhouses which allow for food production; insulation… must be factored in for ALL systems to accurately determine whether they are similar or different in performance.
  • None of these systems appears to factor in maintenance costs.
To us, the most important piece of this research is in this quote:  

"Bottom line: build an energy efficient, water efficient house anyway you can - and get off the grid…” 

 or, put another way, the techniques used in making earthships work…
can be used across systems to make ALL architecture work better!