You are thinking on it in the wrong way: - It's not installing solar to do home mining. - It's using home mining to consume your wasted or unused solar energy. It's not about building a mining operation in your house. It's about making more profitable your solar installation while helping the decentralization pleb-mining. So, for your opex calculation your energy costs are zero, as you are going to consume unused energy. The good old S9 has a breakeven of $0.04/kWh right now, operating in efficient power range ofc. A pair of them can chew up something between 10-15 kWh per day, that could be $0.4 or $0.5 a day. You are not going to be financially independent with that, of course!! 😊 But in a few months your (small) miner capex are paid, and your mining rewards would be 100% profits, although small! 😁 You can scale this up with newer miners adapting to your wasted energy case, or reuse the produced heat to help warming up your house. Btw, buying Bitcoin is not exclusive to home mining with wasted solar energy, of course! 🫂