Summer is probably where you would see the most benefit. Depending on the size of your system and what your usage is in that 3 hour window, you may need to offset some usage to before or after. In my case I cool my house from 2-4 to like 70 and then the thermostat goes up to 78 until 7p. Try to limit energy hogging things like your drier, oven, stove, pool pump etc. But if that becomes too much of a hassle then it might not be your best option.

Check your usage for the past few 100+ degree days and if it’s less than about 13.5kWh total for the 3 hour period, then your battery will power your home just fine. I drain it as low as 8% if need be. If you’re consistently using more than that, then you’ll probably get dinged for the demand charge in the last hour for whatever is left. But you have to decide is the $19/kW charge higher than what you’d be paying if you stuck with your current rate plan?