Hi new here, so bear with me. I'm trying to learn my calculations for a contractors test. When filling out the calculation table for a service load, how do you calculate when you have no ideal what size of heat and air unit is going to be installed? You call the H&A people up and they give you BTU's (which tells me nothing) and then they finally tell you "You need to run a 60 amp circuit to the heater and a 30 amp to the A/C unit". Would you just use the full wattage capability of a 60 amp circuit for the calculation?