Depending on what your livestock are in the tank, the answer will be vary. 5 hours is not that long since you have a couple of battery powered air pumps; therefore, your fishes would be just fine. As for your corals (if you have any), SPS will be affected the most might since there will be a temp swing. Since it will be at night, 55 -65 F is low, so make sure you keep your water temp stable. I would close all doors and windows to prevent cool air coming in to the room where the tank is located.