We live in Spokane, WA, a high-desert climate. We don't need a programmable thermostat, but we do need one to keep an constant ambient temperature range. This may mean A/C during the day, and heat at night. We have a heat pump. What feature on a thermostat would allow us to automatically switch between heating and cooling?
The feature you want is referred to 'Auto Changeover". But this feature is usually only on the higher end programmable thermostats now.
If you actually need heat at night and AC during the day, that means that your house's level of insulation is so poor that it's really worth adding some.