If your furnace is malfunctioning, causing it to blow cold air through the vents in your home, there could be several problems with your heating system that may be causing this issue. For instance, it could be a faulty thermostat or circuit control board issue, which could be sending a message to turn the blower motor on but not the burner. Without activating the burners, the air being blown into your home will not be heated air. Or it could be that your pilot light has gone out/faulty electric furnace ignition, causing there to be no fire to heat the cold air. Or lastly, your furnace could simply be lacking the fuel necessary to generate heat. Contact Tropic Air Furnace experts to troubleshoot the issue and suggest you the best fix