This is what I think also. A small, grid-independent PV array to run a heat pump mini split (combo AC/heater) combined with lots of thermal mass to hold the cold or heat. But it would very much depend on an individual home's architecture and layout.
I've been reducing my heating/cooling bills...
The M57 motor is proven, strong, and stout as can be. But the twin turbo control system is total garbage. They really needed to specify turbos with position feedback, like many other state of the art turbo cars. They cheaped out.
Yes, this. For goodness sake, people make waaaay WAAAY tooo much of a big deal about such an inconsequential thing. EGR's clog up about once a DECADE now. Goodness, if you put 1/100th of this effort in just MAINTAINING THE CAR, you'd be way happier with it. Worry less. Drive more.
I guarantee if you get granular enough to build a spreadsheet like I did, it does. It dramatically increased warmup times in cool weather. That costs FE, Might not matter if all you do is mostly longish drives, but for the other 80% of people, it's a freaking huge effect.
Restore your EGR to full factory-level OEM functioning. It's killing your winter FE in the PNW. I know. Been there, done that. It's costing you at least 3-8 mpg in winter. Stupid stupid stupid.
Next, detune your right foot.
A tune will improve fun factor and will typically HELP fuel economy a...