[blitzar]

A black body catching some rays would give a decent boost (for part of the day at least) - https://www.youtube.com/watch?v=FtfaZMahSUU - just putting the split unit somewhere that catches the sunshine would probably be a non negligible positive!

Once we go down the heat extraction / transfer path some interesting efficiencies should crop up - any waste heat (higher than ambient temperature) exiting a property could reasonably be captured and used.