My husband installed the rth 8500 and set it to emergency heat as soon as the weather got cold. Our electric billed has doubled since last year with only a one degree temperature difference. I thought this thermostat was supposed to help us save money :(

Tstats have to be programmed to save you money,, but do you have a heatpump?
HP doesn`t work if tstat is set on emergency heat,this sets furnace/airhandler to run all the time

Thank you so much for your answer. This has been a contention in the house for about three weeks now. My husband now has conceded that the system needs to be on heat and all is running more smoothly! I am just hoping to see a MAJOR reduction in our kilowatt consumption on next months bill. :)
By the way, I just want to say that I am grateful for a handy husband that can fix things in our house. He actually installed our heat pump 3 or so years ago, but didn't change out the thermostat at the time because the one we had was still working. Thanks again! :)

Believe it or not at times it could be cheaper to run on emr. Heat than heat pump. If the outside temp is so cold that the heat pump can not keep up and runs all the time. That means your heat pump and your aux heat is on and using electricity. If your system can not satisfy the thermostat in cold weather you are better off switching to emergency heat and shutting down a appliance that is using electricity but not doing any thing. Your heat pump should work fine around 30 degrees much less it will start to struggle and cost you money.