When the winter chill sets in, your furnace easily becomes your best friend. But what happens when it starts acting up? Before you call in the professionals, there are a few troubleshooting steps you can take to try and resolve common furnace issues like a pro. Here’s how you can tackle these problems DIY-style and keep your home warm and cozy. Check Your Homes Thermostat When your furnace starts underperforming, the first thing you should do is make sure your thermostat is actually talking to your furnace! It’s easy to overlook, but double-check that the thermostat is set to “heat”…