My purchase is fairly knew, but my impression so far is a full 4 gallon tank is going to take over an hour. That is somewhat a function of the area you are covering and includes moving extension cords to new outlets. I recommend using 12 gauge or at least 14 gauge wire extension cords and keeping the distance back to the outlet as short as possible. If you have a new unit with the new switch on the nozzle model, then if the hose is warm you possibly have too much line loss for the cords for the unit.