There are only two things that determine the value of a self-storage property, the CAP rate, and the net operating income of the self-storage facility. For example, if the CAP rate for your area is 6.5% and you are able to sell your self-storage property for a 5.5% cap rate, you were able to get a great deal. (You take the Net Operating Income and divide that by the CAP rate to get the current value of the property.) Understanding the importance of the net operating income and the cap rate in relation to the value of your property is critical. If you have a low net operating income, you are going to have a lower sales price.