> an average home battery system costs between $10,000 to $20,000

What size is this? In the UK you can get a 16kWh LFP battery for £2,700. I believe an inverter would be £1,500.

This would cover one day of electricity usage for me if you exclude EV charging, double it to include that too. Note that my heating is gas.

I’ve considered getting a setup like this just to charge it at night at 7p/kWh and use it during the day to save paying 30p/kWh but the ROI of saving £100/month is slightly too long. If prices come down further I’ll probably bite.