Trying to figure cash on cash ROI on current home

[Rickey Davis]

I bought my house for 220k five years ago. It is now valued at 290k. I put no money down and I'm trying to figure out if is worth selling or renting. When trying to calculate cash on cash ROI what number would I use for my initial investment? Would I use the amount that I have paid down these five years or the value that is worth due to appreciation. Or would I not use this at all seeing a started with no money down? Just need to understand how to calculate before I decide to sell or rent.