We have a heil gas furnace that is about sixteen years old and for the last two winters it has been blowing cold air. But not consistently. Sometimes it will actually blow warm air. When it blows cold air it just keeps running because it does not come up to the temperature of the thermostat. We have had a repair man come twice so far and still having the same problem. First visit he cleaned the ignitor. Second visit he replaced it. This is costing a lot for him to keep coming and not fixing the problem. HELP!

Time to change your gas furnace is come I guess

You should be able to get 20-25 years out of that furnace. Ask friends and family for a good hvac person. Tell this person the history and ask for his opinion and recommendation for a fix.

Check out the info here, too:
https://www.heil-hvac.com/en/us/buyi...ir-or-replace/