I was reading the post from the link below. I had a question with regard to that line of discussion. I can post there but it was old. I have a GE main service box, 24 positions, that has a double pole 125A main breaker.
There is currently a 40 Amp double taking up 4 slots on the right side for an apartment size electric stove. There are 4 more circuits for plugs, and a regrigerator is on one of those. I will add a disposer onto the kitchen circuit but that only has the overhead light plugs. The main service is for a 450sf tiny apartment of one bedroom, a bath and kitchen. Its being renovated but budget is tight.
I want to add breaks for a 24Kw on demand water heater and a small split unit AC. Water heater at 240V, requires two 60 amp breakers, and the AC, MRCool, 18K BTU, will require a 15A to 20A, double pole.
Can the main service that is currently in operation accomodate the additional load. I know the breakers will fit fine. Looks doable to me.