We had the opposite problem. We replaced our non-programmable thermostat with a programmable honeywell 5-2 day one (our first DIY job in the house). Although it states that you should set the temperature and time exactly and it automatically warms the house up to meet that time (i.e. if you set 7am and 70 degrees, it should warm the house up to be 70 degrees at 7am), we found this didn't work. At 7am the house was 60 degrees. It took some fiddling with the settings and I also balanced the furnace and closed the vents in the rooms we don't use often.
There should be setting to change the temperature between F and C to whatever you're comfortable with...that's pretty standard and can be changed in the settings menu which should be in your instruction book. Personally I still think in F, even though every country I've ever lived in primarily used C
