Just saying 24 months is NOT the correct way. There SHOULD be a question asking if it was ever NOT your Principal Residence. In your case, PART of your profit should be taxable (plus gain due to the depreciation).
In a nutshell, if you owned the home for 14 years and it was NOT your Principal Residence for 6 year, you are NOT allowed to exclude 6/14ths of the gain, and that 6/14ths of the profit will be taxable (plus the gain due to depreciation). The actual calculation uses days, so you NEED to find that area in the "Sale of Home" section where it specifically asks for the number of days you owned it, and the number of days it was not your Principal Residence (after 2008). Again, these rules apply because you used it as your Principal Residence AFTER it was rented.
