[dnu]

Yes, but it can also use several channels. This plus the AC standard becoming more popular will lead to overcrowding in 5 GHz also.

2.4 GHz has 3 non-overlapping 20 MHz channels.

5 GHz has about 23 non-overlapping 20 MHz channels.

Both go through walls, so you will get interference from neighbouring apartments no matter what technology you implement. The only solutions are to use a much higher frequency, or shield your apartment walls.