[stevehull]

Memphis,

I have read that article and it again sounds encouraging. But I have read many of these "no mold earth tube" techniques over the years.

When corrugated tubes are used, you can get substantial mold now growing in the dirt that is drained at each point in the tube. Mold also needs air - and together with moisture, warmth and dark you still have the "recipe" for mold.

Build a small tube and use it for your fireplace/wood stove make up air. Easy to test for mold spores in that trial aspect.

We are recognizing that mold can be a very dangerous situation with it causing many other issues - some quite dangerous. Older homes had some mold, but they were also so loose and drafty that it was not a substantial issue. But couple a tight house with low air changes per hour (ACH) and then a mold introduction section, then you have danger.

Mold is not something that you take away and the medical problems disappear. Mold seems to trigger a whole pathway, that once initiated, continues to cause a lot of medical problems. Allergists find this very frustrating.

Recall underground homes from the 1970's? Another great idea that minimized the heating cooling delta t, minimized air infiltration, etc? The idea was to cover the outside of the concrete structure with foam panels to prevent critical dew point condensation on the interior walls. But ANY tiny gap in that exterior insulation and condensation (and mold) occurred.

Interior condensation remains a big problem and many of these homes had to be complete covered now on the inside with insulation panels to prevent dew point condensation (and mold). But that just kept the mold behind the panels where it was now dark, humid and wet. Eventually mold spores get out and again cause home air quality issues.

I do a lot of work for the American Lung Association (allergy and construction issues) and we are coming to the conclusion that mold is far more of a home problem than we ever imagined. Tight homes, when ventilated properly with ERVs, still can have critical mold issues. The key is to prevent mold and not just to wash it away with more air changes.

Underground construction is now waning as above ground envelope techniques and better insulation and installation techniques nullify the low delta T aspect.

You have seen the power of the geocoupled heat pump. I would use that technology first, but give the fireplace tube a try.


Steve