Should I combine two units or use one as an Air B&B?

[Bruce Clark]

I recently purchased a two story building. The first floor is occupied by a computer company, and they have already signed a lease with me. The second floor needs a complete rehab. The second floor currently has two units. You come up the stairs and on to the left is a decent sized one bed, one bath unit. On the right is a small efficiency unit. It's basically one room with a bathroom. It previously had a kitchenette, but it has been removed. In my market, efficiency units are hard to rent, and they really are not worth the hassle. My initial thought was to simply combine the units, and create what would be a large 2 bedroom, 2 bath unit. This would probably rent for around $900 per month as apposed to the one bedroom, which would rent for about $600. 

My other thought was to keep the layout as is, and use the efficiency as an air B&B. I have no experience with short term rentals, so I am not certain how to weigh this option.

What research should I do? What costs and expenses are involved with short term rentals? What else should I consider?

All comments, insights, advice welcome. Thank you in advance!