Low-energy houses covered by earth

Recently, I saw footage of melting glaciers in some document and it sent a chill down my spine. I started to doubt whether we had sufficiently insulated and buried...

Both houses were built with a limited budget, partially through self-help, using traditional technologies, for young families, with a requirement for normal contemporary architecture. And above all, both had access to a premium building plot - Záhorčice on the southern slope with a perfect view of the valley and the Novohradské hills, Vidov on a southwest terrace on a steep slope with a perfect view of the České Budějovice basin and Mount Kleť.
The normal building program did not in any way degrade the effort to realize energy-efficient houses. It was not a naive intention under the pressure of pseudo-ecological agitation or a lobby of sellers of heat pumps, solar technologies, and photovoltaics to create a perpetual motion machine, but rather an ordinary effort to consume less - mainly to heat less.
I visited the plots several times, several times I wet my finger and determined where the north wind was blowing from - and that it occasionally blew - so we ultimately partially buried them.
No new idea - analogies can be found both in the Czech Republic and around the world (e.g., Wright's "Solar Half-Circle" for H. Jacobs in Middleton).
The houses have brick walls, with the visible surfaces designed in the form of a sandwich, Záhorčice has a layer of thermal insulation clad with larch boards and a facing of rubble stone, Vidov is finished with panels of varnished waterproof plywood or fitted with an external thermal insulation system. The vertical structure at the junction with the terrain - the buried part - was meticulously addressed. Due to the pressure of the earth, wider brick walls were used, and brick partition walls and reinforced concrete filigree ceilings also serve as stiffening.
Both houses have green roofs with extensive planting continuing into the surrounding terrain. This of course takes into account the statics of the ceiling structures.
In both cases, drainage systems were thoroughly addressed - Vidov is located on a steep slope with the possible occasional occurrence of pressurized water. The drainage collection pipes are arranged at several height levels. The final landscaping is designed so that surface water from the roofs flows away from the house.
Both houses are generously glazed in the main living rooms on sunny walls and their overhangs allow for thermal gains on sunny autumn and winter days due to the elliptical path of the sun. Conversely, in regard to the azimuth of the high summer sun, the overhangs prevent overheating of the houses.
Although the houses are not unusually designed and, due to their shape and architectural design, have a relatively unfavorable geometric characteristic A/V = approx. 0.9 m²/m³, we were pleasantly surprised by the total heating costs after the preceding extreme winter. In the case of Vidov, where the beginning of winter (new building) involved intensive ventilation, the heating or gas costs were about 11,000 CZK including VAT, and for Záhorčice, where heating is done with an electric boiler (+ occasional supplementary heating with a fireplace insert), it was a similar amount.
I notice a somewhat twisted logic in the approach to low-energy or energy-efficient houses. When we go the alternative route, we often overly focus on modern, sophisticated heating, ventilation, recuperation methods, etc., which require considerable resources and sometimes even nerves from users, instead of at least equally energetically dedicating ourselves to minimizing the heat losses of our houses and their energy demands. I do not see a problem in correctly orienting a house in relation to the sun and prevailing winds, sensibly working with space, maximally insulating it, and only then addressing how and where to obtain that small amount of energy for its operation. And would these constraints in any way degrade the architecture itself or hinder the creative expansion of the authors and their egos? Perhaps they will come to terms with this when viewing melting glaciers and continually rising oil prices…

And what should be avoided when building and designing such a house? Perhaps just resigning to this intention when promoting it at offices, for whom it is primarily a house with a flat roof - "… surely you don't want to build this in a South Bohemian village…?"