Our house was built in 1958 and we just moved in a year ago. We had to turn our heat to 80 to heat our upstairs. In the summer it is hot and the winter it is freezing. Could our thermostat need replaced or what is it? Any ideas??

Check the vents to ensure it's not closed or blocked?

Sounds like the system design (duct work) might be worth looking at , Good luck, Mike