My two-story home in Virginia has one thermostat controlling natural gas heat on the main level and a second thermostat controlling a heat pump upstairs. I have been warned against installing a programmable thermostat upstairs (may actually increase the heating costs for a heat pump), but am I o.k. to install a programmable thermostat on the main level? In other words, will the temperature downstairs dropping during the night and warming in the morning affect the heat pump upstairs (make it less effecient). Thank you!
Jason

If you are turning the heat up and down manually, all the programmable thermostats does is remember to do it for you. Turning the heat down usually but maybe not always saves energy. If you think the programmable thermostats are worth it, I would go ahead for both zones. Make sure what you buy is suitable for use with a heat pump. Many of them aren't or require extra steps to instal.