A thermostat number is easy to compare with someone else's, but it is only part of the cooling picture. Insulation, humidity and the condition of the system also affect how a home feels.
The U.S. Department of Energy's home heating and cooling guide recommends choosing the highest temperature that remains comfortable during summer. It also points to practical maintenance: keeping vents clear, following the equipment manual and cleaning or replacing filters as needed. A lower setting cannot repair restricted airflow or neglected equipment.
A programmable thermostat can return the home to a preferred setting before you arrive. The department also advises considering pets when making adjustments. The aim is a comfortable, properly maintained home, rather than copying a single number without considering who lives there and how the space behaves.
Sources: U.S. Department of Energy: Home Heating and Cooling Original linked story