From an inexperienced, non-architect/engineer or builder, rambling perspective in regard to the House Within A House letter to the editor, perhaps some consideration should also probably be given to having a Trombe Wall feature instead of, or in addition to, the envelope design. The latest information can be found at https://www.eebt.org/Trombe.html
This is a thermal mass wall with a temperature moderating function which was exposed to the sun behind a glass window facing south. The feature also could aid with natural/solar-heated air movement.
I saw this feature working approximately 30-35 years ago in a couple of houses with a floor-to-ceiling wall. They had small, 8” X 16”openings (concrete block sized) both high and low in the wall. At these display houses, light-weight ribbons were hanging from the top of the openings and moving, indicating the natural circulation without any electrically-powered forced air.
However, and in reality, the display houses seen by me, of both the Double Envelope design and the Trombe Wall features were not cost effective, as built at a Midwest, near 37 degree latitude location, some 30-35 years ago.
An increased efficiency performance for either building principle could conceivably further be achieved by having strategically sloped ceilings in a single story house. This in addition would have some sound deadening qualities.
Assuming a non-envelope design, near standard construction of a two-story house were to be built: Conceivably increased performance could be achieved by utilizing part of the envelope principle by having floor openings at the back wall and at the front second level floors and at the south, sun exposed floors, with vertical, interior wall openings. Conceivably, the colder air would sink to the lower level floor, where it would move naturally to the south facing window, to once again be re-heated and re-circulated.
Going further, exterior inlet window/vents on the lower level of the (shaded) north, and higher level exhaust window/vents on the extreme upper south sides of the house would help with natural cooling and regulating or releasing heat build-up.
Additionally, using moveable, shading, awnings, or extensions to the roof overhang would also help. Another possibility in the interior, would be using mirrored, reflective, pull-up blinds (instead of down blinds) on any sun exposed windows.
I am of the opinion, if the above referenced building design and features were used in practical moderation, they are economically feasible, in my opinion. In conjunction with hopefully today’s more enlightened and better builders, materials, careful building practices and processes, cost-effective, energy-efficient buildings could be built, again in my opinion.
Old Mother Earth News and no longer published Solar Age magazines provided insight into these energy efficient building concepts, the builder’s names and books.
With apologies for the rambling…
Please don’t apologize. You have some wonderful ideas here and I’m sure that many of our readers can use them in considering off-grid energy alternatives for their homes as a way to lessen their dependence on the power grid. In fact, my husband and I designed an underground house one time using some of these very principles. Unfortunately, cost made the home out of the reach of our pocketbooks at the time. (We had million dollar dreams on a 10 cent pocketbook!) However, I believe you make very valid observations. Thank you for writing.
I built such a house (envelope house) in 1981 and lived it for two winters. It works quite well, although not by the original theory that is by convection. The earth coupling of the solarium and high insulation explains it. It won’t freeze even untended. During long cloudy periods, some backup heating is required to be comfortable, such as a wood stove in the evenings. Mother Earth had a few articles on it. The biggest advantage is you can build a fairly conventional home as the solar is around it, instead of building the home around the solar system.
Thank you so much for letting us know how this home worked for you. For those of you interested in these designs, here is a pdf link to the paper on it that was done on the envelope home by the National Research Council of Canada. In addition, here is a link to a free book titled Passive Solar Energy — The Homeowner’s Guide to Natural Heating and Cooling. There is some helpful information in it as well.