After that, I lowered the hallway thermostat setting enough to get her bedroom near 74 F (23.3 C). There is no single thermostat setting that is right for every person or every home. So there’s not one temperature setting that’s maximally energy- and cost-efficient for every home. While a thermostat setting of 78 F (25.6 C) is often touted as a solution, in reality it is just one of several options. In my house, becoming a mother changed the amount I determined was necessary to spend on my summer cooling bills.