The problem of proprietary systems and single vendor lock-in are enough for at least some segments of the US military to ban their installation. https://vrfrej

The problem of proprietary systems and single vendor lock-in are enough for at least some segments of the US military to ban their installation. https://vrfrejected.org/case-studies/ https://vrfrejected.org/case-studies/ The availability of multi-speed or variable speed compressor (inverter drive) is extremely limited in the residential market space outside of anything proprietary because there isn't enough cost flexibility. It doesn't help that American manufacturers are at least 20 years behind the Japanese and Korean makers on developing these. It generally doesn't make sense for the manufacturers that have the tech to make open hardware systems for this market segment when you're only talking about $1000/ton for residential hardware. The lock in is more valuable than the initial sale is my guess. I think one could likely home brew an open-hardware variable speed system by retrofitting a standard three phase compressor and variable frequency drive (see Jeremy Fielding's youtube channel—linked below) to their residential unit but it is hard to find a small enough three phase compressor and wouldn't probably be mass marketable because even single stage units are often good enough for most residential applications. Future building code adoption will probably have an influence on this particularly in the areas where ventilation requirements are tightened. https://www.youtube.com/channel/UC_SLthyNX_ivd-dmsFgmJVg https://www.youtube.com/channel/UC_SLthyNX_ivd-dmsFgmJVg