I have a danby model DPAC5799 was given to me with

You don't need to have an external exhaust if you are going to use it as a dehumidifier. Go to the mode button and click it until it goes to dry and then set the temperature a lower than the room. This should be all you need to do. I have had mine running all day and the room seems dry however I have had very little water (almost none) to empty from the reservoir. I don't know if this is a problem but maybe you can let me know how yours performs.