Last updated on January 15th, 2024 at 07:05 am

There is no such thing as a good time for your HVAC system to fail, and the winter months are a particularly bad time to be left without heating. If you can, you’d probably rather attempt HVAC troubleshooting yourself instead of waiting for a repair professional.

It is important to routinely get professional maintenance for your HVAC system, but even the best-maintained system can fail at the worst time. While you should call in the experts for routine maintenance and any needed repairs, there are a few things you can do yourself to potentially fix your own heating system.

First, let’s start with the basics.

What is HVAC?

HVAC stands for Heating, Ventilation, and Air-Conditioning. Your AC, Heat Pump, and/or furnace are all parts of a complete HVAC system.

While HVAC troubleshooting often requires an expert touch, some issues can be easily and quickly diagnosed. Here are a few places to start:

9 HVAC Troubleshooting Tips

1. Check the Power

It may seem unlikely, but a surprisingly large number of HVAC problems can have simple solutions. If your system isn’t turning on, the first step is to rule out simple problems like lack of power.

Start by checking your breaker, and making sure it hasn’t flipped or blown a fuse. Try flipping the breaker and waiting a few seconds before turning it back on.

2. Try an HVAC System Reset

If something isn’t working, one of the first steps is to reset the system. Every furnace, air conditioner, or heat pump has a different reset method.

Check your owner’s manual to learn how to reset the system. If you don’t have the manual, you can find them online by searching the model number of the system.

3. Close the Furnace Door

Many furnaces have a switch that prevents them from operating when the service door is open. If the furnace isn’t producing any heat, open the service door and shut it again. Check to make sure that everything is shut tightly and then try to turn the heater on again.

4. Check the Thermostat

Thermostats are often the cause of many HVAC problems. A faulty thermostat can lead to many different results, including the system turning on at the wrong time or not turning on at all. One of the first steps is making sure that the thermostat has power. If it is battery-operated, try changing the batteries, even if it seems to be working fine.

If the thermostat is getting power, check and make sure your temperature settings haven’t been changed. Incorrect temperature settings could be caused by children, the thermostat resetting, or simply buttons being pressed accidentally. Make sure all your settings are right before moving on from your thermostat.

5. Install a New Filter

If your HVAC system hasn’t been working quite as well lately, the air coming out of the vents seems dusty or humid, or it has been a long time since your system has received maintenance, it may be time for a new filter. Dirty or old filters can reduce air quality, lead to inefficiency, and reduce airflow from your vents.

While you may be able to replace air filters yourself, it is best to have an expert perform the maintenance. An HVAC service technician will be able to properly maintain your system and spot potential issues when they change the filter.

6. Check Vents for Obstructions

If certain parts of your home aren’t getting heated or cooled very well, it is important to check your vents. Sometimes, a vent can get shut or covered without you noticing. Check to ensure that vents are free from dirt, dust, or foreign objects that could obstruct the flow of air.

7. Turn Off the AC

In the summer months, if your AC has been on for an extended amount of time, it is possible for components to freeze preventing them from properly cooling. If your AC doesn’t seem to be cooling, turn off the AC and turn on the fan for a while before trying to use it again. If this doesn’t fix it, or the problem occurs frequently, it is time to call in the experts.

8. Check the Wires

Sometimes wires get disconnected or damaged. This can be more common for outside AC units, where exposed wires can be damaged by landscaping equipment. If your system won’t start, it can’t hurt to check. Make sure to be careful and don’t handle any potentially damaged or exposed wires, as they could carry the risk of shock.

9. Call an HVAC Technician

Diagnosing problems with your HVAC system can sometimes be simple, but often it is better to leave it up to the professionals. If the cause of a problem is unclear, or the fix is complicated, it’s time to call in the experts. Many problems with furnaces, AC units, and heat pumps require extensive training to fix and trying to do it yourself could lead to damage and even voided warranties.


In summary, here are 9 tips for troubleshooting your HVAC system or heater:

  • Check the power.
  • Try an HVAC system reset.
  • Close the furnace door.
  • Check the thermostat.
  • Install a new filter.
  • Check vents for obstructions.
  • Turn off the AC.
  • Check the wires.
  • Call an HVAC technician.


Paragon has years of experience diagnosing, fixing, and maintaining HVAC systems. Our team of experts would love to help you with your heating and cooling needs. Paragon serves clients throughout Snohomish and East King Counties, including Everett and Bellevue. Our technicians are certified, trained, and highly experienced. Contact us today!