Perfect timing! Just as it is starting to get cold, finally, my upstairs furnace decides to go on strike. The furnace itself is only about 10 years old but the thermostat is original. Like 1985 original. The kind with the mercury bubble in it. So this is what’s happening: when I turn it on, it makes the normal start up noise, the normal heating noise but only makes that noise for about 10 seconds then kicks out cold air. My thought is a fried thermostat but I’m looking for ideas and recommendations for a HVAC person to come out that won’t drain me and is honest. *side note: this furnace is in the attic and was replaced about ten years ago due to a fire around 2008. Thank you all for ideas!