Can you recommend cost-effective auxiliary HVAC solutions for a passive solar home?
Our architectural studio recommends comparing your passive solar home to the passive house technology. The Passive House Institute U.S. provides a great description of the concept and how it works.
The homepage of the U.S. Department of Energy gives a great definition of passive solar home design and has very helpful information to compare the auxiliary heating and cooling systems. We recommend hydronic radiant floor heating and geothermal heat pumps for both heating and cooling because of their high efficiency. Remember that systems based on water (liquids) transport energy far more efficiently than air systems.
Great products such as solar hot water systems for space heating, radiant floor heating and much more are provided by Stiebel Eltron.