I would definitely not do this. The amount of money you save wouldn't be worth the ultimate cost. The skimmer and power heads also add oxygen to your water.
I often turn my skimmer off at night after feeding my tank and dont turn it on till morning before i go to work. Its ot a big deal really but I dont think you will be benefiting cost wise any.
Unless you are running a reverse-photoperiod style refugium to offset the oxygen production/consumption, not a great idea. Even so, achieving appropriate balance of oxygen demand would be painstakingly tedious!