They come with a built-in bed, refrigerator, and bathroom. There's a communal kitchen in central areas of the building.
Some may say the best part is that they are very inexpensive. The apartments are being rented out for $425 per month, and they're going fast.
Mulhair says not everybody needs or wants a big apartment. They would rather save money instead.
Mulhair says he got the idea after staying in traveler hostels in Europe.
CNN contributed to this report.