Dallas–Fort Worth · Homeowner guide
How to Change Your HVAC Air Filter—and Why Your AC or Heater May Not Work
Learn when and how to replace your HVAC filter, what to check when your AC or heater stops working, and when to call for service in DFW and Greater Houston.
A clean air filter is one of the simplest ways to maintain a ducted HVAC system. It helps keep airborne dust out of the equipment and supports airflow. A dirty filter can contribute to weak cooling, a frozen evaporator coil or heating problems—but replacing it will not fix every malfunction.
This HandyNauts guide is for homeowners in Dallas–Fort Worth, including Carrollton, Plano, Frisco and nearby communities, and Greater Houston. Start with the instructions for your equipment and filter. Systems differ, and maintenance should match the installation.
How often should you change your HVAC filter?
Inspect the filter every month, especially when heating or cooling runs heavily. Many disposable filters need replacement about every 30–90 days, but follow the filter and equipment instructions and replace a dirty filter sooner. Pets and pollen can affect the interval. A calendar reminder helps you check before airflow suffers.
Do not assume every filter lasts three months. Different filter types and installations have different requirements. Keep a spare of the correct size and record each replacement date.
How to replace the filter properly
- Turn the HVAC system off before changing the filter. Follow the equipment instructions for safely accessing its filter compartment.
- Locate the filter. It may sit behind a wall or ceiling return grille or beside the furnace or air handler. Check the manual if you are unsure; do not climb into an unsafe attic or open electrical compartments.
- Confirm the specified filter dimensions before buying a replacement. Check the old filter label against the equipment requirements.
- Remove the old filter. Most disposable central-system filters should be replaced rather than washed. Only clean a reusable filter according to its instructions.
- Insert the new filter with the airflow arrow pointing toward the furnace or air handler. At a return grille, that normally means into the wall or ceiling, toward the equipment. Follow any installed airflow markings.
- Refit the grille or filter-compartment cover, restore operation according to the manual and note the date.
The filter should fit its intended slot correctly. Ask an HVAC professional if the size, filter type or direction is unclear. A filter change is routine care, not a substitute for equipment maintenance.
Why is my AC running but not cooling?
Common possibilities include an incorrect thermostat setting, restricted airflow from a dirty filter, a frozen evaporator coil, refrigerant problems or an outdoor-unit fault. These symptoms overlap; testing is needed to identify the cause.
Check that the thermostat is set to Cool and the target temperature is below the room temperature. Inspect an accessible filter and look for visible ice without removing equipment panels. If ice is present, stop cooling and arrange service rather than repeatedly restarting the system. Refrigerant checks and repairs require a professional.
Why will the AC not turn on?
A thermostat problem or loss of electrical power may keep the system from starting. Check the thermostat display, settings and batteries if the model uses them. Note any visible breaker trip for the technician; do not repeatedly reset a breaker or open electrical covers. If ordinary thermostat checks do not resolve the issue, request diagnosis.
Why is the heater not working?
Start by confirming Heat mode and a target temperature above the room temperature. A clogged filter or blocked supply and return vents can restrict airflow. Power, ignition or other equipment problems may also require diagnosis.
A furnace and a heat pump operate differently, so include your system type when requesting help. Do not attempt gas-valve, ignition, wiring or safety-control repairs. If the settings and accessible filter look correct but the home is not warming, schedule service.
What if I smell gas or a carbon monoxide alarm sounds?
Leave immediately and call 911 from outside or a safe distance. For a suspected gas leak, also contact your gas utility’s emergency line. Do not remain inside to troubleshoot the heater. Stay outside until responders say it is safe to return.
What should I send HandyNauts before an HVAC visit?
Send your city and address, thermostat settings and display photo, equipment model-label photos, filter size and last replacement date, and a description of the symptoms. Tell us whether the indoor fan and outdoor unit run, whether the issue affects heating or cooling, and whether you see ice or water. Take photos only where safely accessible.
HandyNauts HVAC diagnostics start at $225 and include the first hour. Additional repairs and materials are explained before approval. We can review maintenance needs as well as heating and cooling concerns across our DFW and Greater Houston service areas.
Get help with heating and cooling
Explore HandyNauts HVAC services, read HandyNauts customer reviews, or request an estimate. Regular filter checks are a useful first step; persistent comfort problems deserve a diagnosis before parts are replaced.
References and further reading
ENERGY STAR maintenance checklist Trane filter replacement guide Carrier AC troubleshooting guide Carrier furnace troubleshooting guide Atmos Energy gas-leak safety CPSC carbon monoxide safety