The Most Common DIY Furnace Fixes—and When to Avoid Them

As the colder months roll in, many homeowners in the Dallas-Fort Worth area rely on their furnaces to keep their homes warm and comfortable. Furnace breakdowns are inconvenient and, in some cases, can leave you without heat during a cold snap. As a result, many homeowners might be tempted to attempt some DIY furnace fixes to avoid the hassle or cost of a service call. While there are some simple tasks you can do yourself, it’s important to know which fixes are safe and which ones should be left to professionals.

At Texas Air Authorities, we believe in empowering our customers with the knowledge they need to maintain their systems. In this article, we’ll discuss the most common DIY furnace fixes and outline when it’s best to call in the experts.

1. Changing the Air Filter

DIY Friendly: Yes

One of the simplest and most effective furnace maintenance tasks you can do yourself is replacing the air filter. Air filters trap dust, dirt, and debris, preventing them from entering the furnace and reducing its efficiency. Over time, these filters become clogged, making it harder for the furnace to circulate air, which can lead to system strain and higher energy bills.

How to do it:

1. Locate the filter, typically near the return air duct or inside the blower compartment.
2. Remove the old filter and replace it with a new one of the correct size.
3. Ensure the filter is facing the right direction, indicated by arrows on the frame. 

Changing the air filter regularly (at least every 1-3 months, depending on use) can extend the life of your furnace and improve indoor air quality. If you’re not sure where the filter is located, check your furnace’s manual or ask a professional.

2. Checking the Thermostat

DIY Friendly: Yes (with caution)

Before you panic about your furnace not turning on, check the thermostat. Sometimes, the problem is as simple as the thermostat being set to the wrong temperature or mode (e.g., cooling mode instead of heating). If the thermostat uses batteries, a dead battery could also be the culprit.

How to do it:

1. Make sure the thermostat is set to “heat” mode and that the temperature setting is appropriate.
2. Replace the batteries if your thermostat is battery-operated.
3. If the display is blank or malfunctioning, try resetting the thermostat (check the manual for specific instructions). 

However, if the thermostat is malfunctioning or doesn’t seem to control the furnace properly even after troubleshooting, it’s time to call in a professional. A faulty thermostat could be causing your furnace to cycle irregularly or not turn on at all.

3. Clearing the Condensate Drain

DIY Friendly: Yes (for certain models)

Modern high-efficiency furnaces often have a condensate drain to collect water produced by the furnace’s heat exchanger. Over time, this drain can get clogged, causing the furnace to shut down due to an overflow. If you notice your furnace turning off frequently or displaying an error code related to drainage, this might be the issue.

How to do it:

1. Locate the condensate drain pipe (usually a white PVC pipe).
2. Check for any visible obstructions or debris.
3. If the pipe is clogged, you can use a wet/dry vacuum to suck out any blockages, or carefully flush it with warm water. 

While cleaning the condensate drain is an easy fix, don’t attempt it if you’re unsure about the process. Improper cleaning could lead to water damage or damage to other furnace components.

4. Resetting the Furnace

DIY Friendly: Yes (in certain situations)

Sometimes, a furnace may shut down due to a temporary issue, such as a power surge or an overheat cycle. Most furnaces have a reset button that can be used to restart the system.

How to do it:

1. Turn off the furnace at the power switch or circuit breaker.
2. Wait 30 seconds to 1 minute to allow the system to reset.
3. Press the reset button (if your model has one) or turn the power back on at the circuit breaker. 

However, if the furnace continues to trip the reset button or shut down after resetting, there may be an underlying issue that requires professional diagnosis. Repeated resets could signal problems with components like the ignition system or limit switch.

5. Inspecting the Ductwork for Leaks

DIY Friendly: Yes (for small leaks)

Leaky ducts can reduce the efficiency of your heating system and lead to higher energy bills. If you notice uneven heating throughout your home or feel drafts, there may be a leak in your ductwork. While larger leaks or major ductwork issues should be handled by a professional, small, visible leaks can sometimes be sealed on your own.

How to do it:

1. Inspect the visible ductwork for any signs of gaps, holes, or loose joints.
2. Use aluminum foil tape (not duct tape) to seal small leaks.
3. If you notice extensive issues, or if the ductwork is located in hard-to-reach areas (attic, crawl spaces), contact an HVAC professional for a full inspection and sealing. 

When to Avoid DIY Furnace Fixes

While there are several furnace tasks you can handle yourself, there are certain repairs that should always be left to professionals. Attempting complex or dangerous fixes could result in costly damage, void warranties, or even pose safety hazards. Here’s when to avoid DIY fixes:

1. Gas Leaks

If you suspect a gas leak or smell rotten eggs near your furnace, leave the house immediately and call the gas company and a licensed HVAC technician. Gas leaks are extremely dangerous and require professional handling.

2. Electrical Issues

If your furnace has electrical problems, such as blown fuses, tripped circuit breakers, or exposed wiring, don’t attempt to fix them yourself. Electrical work should always be left to licensed professionals to avoid the risk of shock, fire, or further damage.

3. Ignition System Problems

Issues with the ignition system (e.g., the pilot light or electronic ignition) can prevent your furnace from lighting properly. These systems are complex and require expert knowledge to repair.

4. Flame Sensor or Burner Issues

If your furnace isn’t producing heat despite turning on, the problem could lie with the flame sensor or burners. These are delicate components that require specialized expertise to inspect and repair.

Conclusion

While DIY furnace fixes can help you save time and money on simple maintenance, it’s crucial to recognize the limits of what you can do yourself. Regularly replacing the air filter, checking the thermostat, and clearing small obstructions are manageable tasks that can extend the life of your furnace. However, more complex issues like gas leaks, electrical malfunctions, and ignition problems should always be left to professional HVAC technicians.

At Texas Air Authorities, we’ve been proudly serving the Dallas-Fort Worth area since 1999, and our NATE-certified technicians are always ready to help. Whether you need a simple repair, maintenance, or a full furnace replacement, you can trust us to keep your home warm and your furnace running smoothly. If you’re ever unsure about a furnace issue, don’t hesitate to reach out for expert guidance and service.

Contact Texas Air Authorities today for a consultation or repair!