I'm glad you asked for clarification and I am happy to respond. While most of the loads in your house are only single phase loads, they are attached to one of two phases coming from the stepdown transformer on the power pole, or the green metal box if you live in an apartment complex. Open your breaker box and you will see that you have two 110 power buses and a neutral bus. By the way, your air conditioner draws from one phase. It is supplied by a double breaker on the same leg, so in actuality it has two 110 volt lines coming to it. One of the hot wires supplies the air conditioners compressor and the other supplies the motor which turns the fan. Anyway, if you were to pull your meter, (which I do not suggest doing - go to an electrical supply house instead), you will see that the socket for your meter doesn't tie at all into the neutral line. On either side of the neutral line are two, (four total), slots for your meter to attach to. It is not attached to the neutral leg at all - it is not reading how much power you are actually using. Therefore, the meter is only reading the two phases, comparing them - subtracting one from the other.
I talked about amps to simplify things. The ac voltage arriving at your house is pretty much a regulated constant with the exception of occasional surges, blackouts and brownouts. Every part of your household electrical system is designed to function at the voltage supplied to your house. Look inside your breaker panel, every breaker is rated in amps. The wiring in your house is rated in amps. Therefore the only thing that is a variable is how much current is drawn through the system. I assumed people would see this was obvious.