Where do you live? Not to come raid your fridge, just to see if Its heating or cooling that you use. There are several passive heating/cooling techniques you could use.

If, as you say the problem arose "lately", it is probably your HVAC being over extended. For starters, buy one of these babies https://goo.gl/4YFNZt (you could return it afterwards :-) and take some images of all the rooms from inside and also from outside the house. It will basically show you if heat/cool is leaking from your house.

Follow it up with educating yourself using something like this provided by your local energy company https://goo.gl/HzY3QZ OR start with a simple checklist like this https://goo.gl/wx55iC and make sure all the bases are covered.

If you want to do spend a little and do a more professional job, get one of such guys in your area to come do an energy audit of the house https://goo.gl/mTmAeg .