Should I add a 2nd bath to my rental unit?

[Shalaye Camillo]

I own a 2 family house in the city (Boston) and currently have a vacant 3 bedroom 1 bath unit which I have been renting fully furnished for 4300/month. I can rent it non-furnished for around 2900. My house is almost 100 years old and the unit was in good/ok condition but needed some sprucing. Since the unit is empty, I'm painting and doing some other things to update it. It's a big unit at 1500 sq ft but, one drawback is there is only one bathroom and it's small. This is typical for a unit of this age in this area. I'm considering adding another full bath room and in unit laundry in current the kitchen area. There are not many units available in this area with 2 full baths and in unit laundry. 

My contractor gave me a good price and overall to add the second bath and redo the kitchen will cost me about 17k. Worst case scenario with second bath and in unit laundry, I could get 3200 for the apartment non furnished and better case 4500 fully furnished. In the short term, I'm not super excited about an increase of only about 300/month but I'm also looking at the value of adding this to the unit for the long term. What would you do?