If it is colder out this year than it was last, you may not be having a problem. The difficulty is that with a few heating degree days, you won't likely need any heat, as you get more you will. What I'm trying to say is that if it is 40 out on average, you end up with 25 heating degree days. When it is 15 on average, you will get 50. At 40 degrees on average, a house with decent insolation won't need much heat added at all; people, refrigerators, appliances and the like provide plenty of heat. To compare you'd have to knock off all the warmer days.