[NiHaoMike]

In one video where someone installed a VFD on a central A/C, the amperage draw went down, not just the wattage. Granted that was under a specific set of conditions (no doubt including an A/C that was oversized to begin with), but that means the overall VA draw also went down.

Maybe what we need is an open source VFD targeting residential HVAC applications, able to drive 120V or 240V split phase motors (depending on components used) and 208V 3 phase motors. It can be designed with both the hardware and software open source, including high efficiency digital PFC. It could even be possible for the software to automatically tune the PFC (output voltage and cut in point) for peak efficiency at a given load condition, while maintaining a user set minimum PF or maximum amperage limit. Some advanced DIYers out there have built their own EV motor drives and chargers. A HVAC motor drive should be quite a bit simpler in comparison.