In unit washer/dryer vs. laundry room in C class area

[Jay Garrison]

I am wrestling with putting in plumbing, vents and stack units for a two flat with garden unit. I estimate I can get an extra $150 to $200 per month for each unit, but I also want to add central air and I am thinking about the cost effectiveness of what would run about $22K altogether - 14K for the plumbing, venting, new stack units and the rest for either mini splits or central air. 

Currently I have a laundry room in the basement, but it could use some upgrades and tenants have to go outside (very briefly) to get to the door down to the basement. The area is improving quickly as Pilsen becomes more expensive, and I am also wondering if it will ever be cheaper to do it. Had I done this 3 years ago, the cost would have been much cheaper for sure.