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Earth tubes

GBA Editor | Posted in General Questions on

Looking for the expert opinions regarding the use of “earth tubes” to temper incoming ventilation air. I understand that in some climates, that moisture must be carefully managed to reduce the risk of mold etc. The idea is appealing for those of us in climates with hot summers and cold winters.

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  1. homedesign | | #1

    You ask a lot of good questions...
    Where are you located?
    My understanding is that Dr. Feist no longer promotes Earth Tubes.
    There is some discussion in this article:

  2. homedesign | | #2

    Here is the Feist quote:
    Feist: There were problems in northern Europe, especially
    in Scandinavia. In Central Europe we haven’t
    had any hygienic problems so far. Actually, I’m not
    sure why we don’t have these problems in Central
    Europe. But I don’t advertise these systems any more,
    mainly because they are too expensive. If you have a
    good heat-recovery ventilator, you don’t need it.

  3. Garth Sproule | | #3

    I live in southern Saskatchewan. Thanks for the link. I agree that the expense would be hard to justify. After thinking about this some more, I suppose that during the swing seasons, especially springtime, that using an earth tube could potentially add an energy penalty from over cooling...

  4. Riversong | | #4

    I think that earth tubes are about as silly an idea as an undergound house. Your mileage may differ.

  5. Garth Sproule | | #5

    If it makes any sense at all, it would work much better with the "exhaust only" ventilation system that you advocate...could use much smaller tube sizing as well...

  6. Riversong | | #6

    You're right that it would make sense for tempering the incoming air for winter ventilation when the earth would be warming it and condensation would not be an issue.

    I've only heard of earth tubes, however, intended for summer cooling in which the condensation problem becomes significant and increases the likelihood of drawing in mold. There are so many easier and less problematic ways of ventilating in the summer that the expense and poblematic nature of earth tubes never made much sense to me.

    I've also discouraged clients from building underground or earth-sheltered homes, since a superinsulated above-ground house can be just as energy efficient at less cost AND have the advantages of views, daylighting, cross ventilation and emergency egress.

  7. Interested Onlooker | | #7

    Earth tubes are described as expensive. What are we looking at as a ballpark cost?

    Let's say this particular piece of string is 120 feet long, 8 inches in diameter and six feet underground. Let's assume you don't need blasting to cut the trench (or you've wrapped it around a slightly larger than normal hole for a basement).

  8. bgarrett | | #8

    I have been searching the net for 6 years and find that "earthtubes were attempted by hundreds in the 70s and 80s" but there NO results posted anywhere that I can find.
    Why is this?
    Mold is not a problem if a heat exchanger is used
    Post 7: 400 feet of 15" PVC cost me $5000, about the same as a central heat/AC system, but of course there are no operating costs of earthtubes

  9. Bob Alf | | #9

    There is a newer earth tube system out that supposedly deals with mold and other issues:
    Anyone had experience with it?

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