Is a single phase power supply sufficient for 2 air conditioners in a house?

If the air conditioner is designed for three phase, then it will not run, and could be damaged, by single phase power. Otherwise, no.

US NEC: You can connect two air conditioners on a single phase power supply, but... The correct question is probably, "Can you connect two air conditioners to a single distribution circuit?". The...

Not necessarily. Two single-phase supplies could be supplying the same phase, which means you don't get the same range of voltage options you get with a true two-phase supply.

Yes as long as the voltages are the same. Two legs of a three phase system can be referred to as single phase.

To obtain a single phase supply from a 3-phase supply you just use one of the three phases. That is, you use one hot and the neutral. Asking this type of question usually means you aren't ready to do...