With the change of the season, you will feel the cool air blowing outside more and more, and… in your home? If your gas oil furnace is blowing cold air and adding a chill to the air inside your home, it’s time to call a professional, and in the event that you haven’t had your gas furnace’s routine repair completed for some time and you have neglected to upgrade your air filter, either of these could indicate the reason why your furnace is blowing cold air, there is a opening that a dirty air filter can prevent air from flowing freely through your oil furnace. This can lead to the furnace overheating and the burner shutting down due to overheating. A lack of warm air from your gas oil furnace can periodically be attributed to something as simple as a pilot light that has gone out, however particularly with older furnaces, it is possible for a draft to cause the pilot light to go out, but besides faulty gas valves or a faulty thermocouple, there are other reasons for an extinguished pilot light. A dirty air filter can cause troubles for your gas furnace, just as other furnace components can cause troubles if they are not properly diagnosed. It could be that a dirty gas burner or a dirty flame sensor is causing your furnace to struggle to keep lit, thus reducing the amount of heat inside your home, however you could be losing a lot of heated air just before it reaches the vents throughout the home if the ducts are incorretly sealed or if they have any cracks or holes in them.