Often it’s just the money. People can’t afford having kids. Cost of living is just to high in all developed countries.

If you have a PV upon your house, the most effective power storage option will be a general power storage, not storing power within the aircon. Doing so, it‘s just accessible by one single device. Instead of all electric devices in the house.

I assume this aircon is targeting apartments in a residential block. But even here, I assume it makes more sense to run a small battery storage such as a camping storage for your apartment and offer power for all your devices, not just a single one.

Oh, that‘s it. I remember my good old tile stove.

Call me naive but I thought that one needs cooling when its hot and the sun burns outside. At that time there‘s plenty of PV energy available. No need for storage, just take it directly.