Troubleshooting
Fix common AC and furnace problems yourself — or know exactly when it's time to call a pro.
Recommended by Rehman Ali, EPA 608 Universal Certified HVAC technician.
Before you pay for a service call, many HVAC problems have simple fixes you can try in minutes: a tripped breaker, a clogged filter, a frozen coil, or a thermostat setting. Our troubleshooting guides walk you through the most common AC and furnace issues step by step, point you to the exact replacement parts when you need them, and tell you honestly when a problem is best left to a licensed technician.
All Troubleshooting Articles
Step-by-step guides straight from a working HVAC technician.
Why Is My AC Blowing Warm Air? 7 Causes & Fixes
Your air conditioner is running but blowing warm air? Here are the 7 most common causes — and the quick fixes you can try before calling a technician.
Furnace Not Igniting? Common Causes & Fixes
Furnace blowing cold air or not turning on? Here are the most common reasons a furnace won't ignite — and the DIY checks to try before calling a pro.