How to tell if its good deal?

[Andrew Bailey]

Hi, I do not own any real estate yet but thinking to change that. After 2 years searching and working with realtor, I finally found 1 deal that I am thinking to buy 

• Its a 2 family house and both units are rented. 
• In Albany NY area, owner has to pay for Water bill and Trash Bill
• Net Income (Cash-flow) = $595
• Net ROI = 5.5% (its low but I think its good for first time bc right now I have zero real estate)
• Cash-on-Cash Return = 16% (I think its good bc 401k retire plans returns are around 8%)

Other things to consider. New Roof

• roof age = 20 years or 240 months (guessing
  
• Cost of new roof $7,000 (guessing)
• $7,000 / 240 = $30 per month (I added this in repairs)

New Furnace (i do not know if this is 2 or 1 furnace)

• Furnace Age = 20 years or 240 months
• Cost of new Furnace $2,500 (guessing)
• $2,500 / 240 = $10 per month (I added this in repairs)

2 new Water Heaters (1 for each unit)

• Water Heater Age = 12 Years or 144 months
• cost of new Water Heater $1,000 Each
• $1,000 / 144 = $7 per month for each water heaters
  

What you guys think? Should I put in offer? also, did I missed anything?