Did you read the sentence after the one you quoted? It then says >On an annual scale with a conventional central A/C, this could result in energy savings of up

Did you read the sentence after the one you quoted? It then says >On an annual scale with a conventional central A/C, this could result in energy savings of up to 11 percent. That's basically what the poster above was claiming (though they seemed to be under-estimating the effect a little). Obviously turning the AC off will reduce the amount of heat leaving the house, but the point is the gains are not super large, even with an inefficient AC and a poorly insulated house. If you have an efficient AC and a well insulated house then the difference could be even smaller (it's even possible that the trend could reverse at some point, if the efficiency of the AC goes down when it is pumping more heat to cool down faster as opposed to consistent low-power heating: you can actually see this in the charts if you look at the mini-split system: it actually uses less energy to turn run the system all the time than to have it off for 4 hours a day, though 8 hours off time is still more efficient). Add in the effects discussed elsewhere in this thread where not all energy consumption is equal from the point of view of the grid and it may even make sense to do the opposite: run the A/C hard during the day while you're not home but green electricity is cheap so you can have it off when you get home and elecriticy demand spikes and solar power is falling off, flattening out the dreaded 'duck curve'.