Question, when you say bye bye,.. you mean you are off-grid now? or is still your meter attached to the grid in a grid tie arrangement?

Also, If your system can't make a total output between 4-5kW don't bother mining unless.. you just want to spend money on a learning experience. Between 2-3 kW will be allocated to the miner. You may use Braiins OS so you can scale back hashrate if you need more power available to your domestic use.

In order to avoid frustration I always recommend that mining should be done at a profit (obvious right?). I don't see solar as "profitable" BUT, it all depends how you look at the investment.

Most ppl I know that have solar here, they want it, period. So basically it acts as a sunken cost, in many cases as a "UPS System" that aims to replace a genset. So in those scenarios, You just need to consider you own generated KWh as 0 cost reflecting no capex returns.

What I would do in that case is calculate how much yearly conservative figure you can get from total amount of kWh and check at an average how much you will need to buy from utility, then average it.

Grid tie systems can work well if you sell the energy to bitcoin through mining.