AC use largely corresponds with peak solar, though, so it doesn't seem like a particularly tough problem to solve? In California, there's often a surplus of solar energy on hot days.
I'm not sure about a surplus. 4-9pm are still peak hours and a quick skim of this CAISO page[1] indicates we're importing electricity during peak hours.
I think the solar generation from say 10am-4pm is where you'd find a surplus, if there is one.
At least at my home, there's only ~20% difference between peak and off-peak rates, but, if you have A/C, it still makes sense to pre-cool on hot days, back it off at 4pm and then turn it back up at 9pm if you still need the cooler temps to sleep.
Maybe not peak, but there is significant overlap, and batteries are cheap enough to cover the gap for the non-overlapping part (e.g. 7-9pm)
Whereas for winter heating, you would want to preheat a lot, and you would also need an oversized PV array, because there's just way less energy available from the sun.
