HVAC Maintenance Guide: How to Keep Your HVAC System Running Smoothly

Gas furnace flames

HVAC maintenance is the last thing anyone wants to add to their yearly maintenance checklist. It is right up there with annual maintenance on a car. Like a car, an HVAC system has moving parts that work together to ensure the home maintains comfortable temperatures. These parts must be checked and maintained for the HVAC system to work correctly.

Yearly HVAC maintenance is an effective way to maximize the HVAC system's lifespan and ensure it works efficiently. It helps ensure the heating and cooling systems work when needed. And it is an excellent way to stay on top of filter changes.

This guide covers everything you need to know about HVAC maintenance, including why HVAC maintenance is important, how often to do it, and what it includes.

Jump to Section

  1. Why HVAC maintenance is important

  2. When and how often should HVAC maintenance be done?

  3. What does HVAC maintenance include?

  4. Cooling system maintenance

  5. Heating system maintenance

  6. Ventilation system maintenance

  7. Ducting system maintenance

  8. Indoor air quality maintenance

  9. Conclusion

Why HVAC maintenance is important

HVAC includes heating, ventilation, and air conditioning and consists of different parts, such as an outdoor and indoor unit with coils, a compressor, fans, motors, filters, and other electronics that work together to control a home's temperature and indoor air quality. Any part within the HVAC system that doesn't work or shows signs of wear should be taken care of or replaced.

HVAC maintenance is essential for a few reasons: first is to ensure the HVAC system is working safely, second is to ensure the system works at all, third is to ensure the system works effectively and efficiently, and fourth because most HVAC system manufacturers require documented yearly maintenance to maintain the system's warranty.

HVAC maintenance can help prevent various problems with an HVAC system, such as restricted filters, restricted indoor or outdoor coils, water leaks, faulty ac capacitors, and electronic failures. It can help pinpoint refrigerant, ducting, and thermostat problems and identifies if the system is likely to trigger a safety switch or has sizing problems.

When done correctly, HVAC maintenance should give the homeowner peace of mind that the system is working correctly and at peak energy efficiency levels. The homeowner should also know if the HVAC system shows signs that raise any concerns and how to address those concerns.

When and how often should HVAC maintenance be done? (Hint: Yearly in the fall and spring)

We recommend HVAC maintenance at least once a year to ensure the system works properly. However, other factors such as how often the system runs, where its located, and the type of system affect how frequently a system should have HVAC maintenance done.

An HVAC system in a dusty environment with lots of debris and poor indoor air quality will get dirty sooner. And systems that use different energy sources, such as gas heating and refrigerant cooling, should be checked at least twice a year so each part can be inspected and maintained at their ideal working temperatures.

The ideal time to get HVAC maintenance on an HVAC system is just before the cooling or heating seasons, ideally in fall or spring. However, this isn't easy to time because that is when everyone needs their HVAC system maintained, and it could result in less scheduling availability or higher prices. When scheduling HVAC maintenance, it is better to get it done earlier than later. That way, any concerns could be addressed and fixed on time so that the system works when needed.

Below we discuss what HVAC maintenance includes and the importance of each item.

What does HVAC maintenance include? (Preventative maintenance checklist)?

An HVAC system includes components that enable the system to heat, ventilate, and air condition the home. All HVAC systems offer a form of filtration to protect the system. But depending on the type of HVAC system, the filter type and other components may vary.

Below we discuss the various checkpoints and services HVAC maintenance includes.

Cooling System Maintenance

The cooling system (and heat for heat pumps) should be checked yearly. The cooling system has an outdoor unit, known as an air conditioning or heat pump system, which includes a coil, electronics, and a compressor. The outdoor unit gets paired with an indoor coil and an air handler, which can be part of a gas furnace or an independent air handling unit.

The cooling systems checkpoints include electrical, refrigerant, and airflow metrics to determine if the system is working correctly and if anything needs to be adjusted or serviced. Other visual and noise observations look for any signs of wear and underlying problems.

Airflow metrics are unique to each system, and each HVAC system has its specifications for airflow requirements.

The electrical checkpoints include checking the capacitors for the outdoor condenser and indoor air handling unit. The amp draws to the compressor motor, the outdoor fan motor, and the indoor fan motor. And checking that proper voltage is received and distributed by any transformers and throughout the control boards.

Ideal electrical readings are unique to each system. The blower wheel fan motor, compressor motor, and outdoor fan motor have their ideal electrical operating conditions specified on the HVAC system. And each capacitor has a microfarad rating that the capacitor needs to meet. An electrical failure will prevent the air conditioning system from working.

A refrigerant pressure reading and a subcooling and superheat temperatures test are done to verify that the refrigeration cycle works correctly. Off readings can indicate a refrigerant leak or other problems with the HVAC system, such as dirty indoor or outdoor coils, restricted filters, or ducting problems.

Each system has a pressure chart that indicates how much pressure the refrigerants should be at a given temperature and the required subcooling and superheat.

A static pressure test ensures the system gets proper airflow so the refrigeration cycle can happen correctly. And the temperature difference is measured for the air going into the system and the air going out to verify this further.

The maximum static pressure a system should have is stated on the air handling unit.

The system is also visually inspected for cleanliness and any signs of leakage or a clogged AC drain line and is listened to for excessive noise or vibrations.

Depending on the HVAC pro's findings, they may suggest an HVAC system cleaning for the indoor or outdoor coil, a refrigerant leak test and repair, ducting upgrades, unclogging an AC drain line, or replacing an electrical component.

Heating System Maintenance

The two most common heating systems are gas furnaces and heat pumps. You can learn more about the types of HVAC systems; however, for HVAC maintenance, heat pumps follow the same maintenance as cooling systems with a little more electronics and a reversing valve.

Maintenance of a gas furnace includes checking and adjusting gas pressures, ensuring proper combustion and exhaust of the flame and fumes, ensuring that the safety switches are working correctly, and inspecting the system's motors and electrical components. High-efficiency furnaces produce moisture condensation, and drainage lines should be checked and cleared during maintenance to prevent leaks.

Gas pressure should be checked and adjusted yearly because the gas supply pressure from the city could change periodically, affecting the pressure making its way into the system. A gas pressure that is too high can damage the burners, burn improperly, increase the risk of carbon monoxide leakage, and cause the system to overheat, which triggers a safety switch.

Inspecting the motors, electrical components, and safety switches ensure the inducer motor works correctly and creates a good draft and that the fumes are exhausted through the FLUE vent pipe. A faulty inducer motor or a blocked FLUE vent pipe will signal the system that there is a problem, and won't start. You can learn more about how a furnace works, but in short, an ignition and operation sequence consists of safety switches that ensure the system operates safely.

The rest of the system electronics must be checked, including cleaning the flame sensor. Failure to clean the flame sensor can cause the furnace not to work because, as a safety precaution, the gas valve will shut off to prevent a gas leak in the home. The HVAC pro will also check the control board, capacitors, and transformers to ensure the system receives and distributes the power correctly.

A carbon monoxide leak test ensures the system works safely. A carbon monoxide leak can indicate that the flames are not burning correctly, that the fumes are not exhausting correctly, or that there is a crack in the heat exchanger.

Depending on the HVAC pros' findings, they may adjust the gas pressure, clean the flame sensor, clear out any blockage in the FLUE vent pipe or pressure switch tubing, and clear any condensation blockage for high-efficiency furnaces. They may also suggest replacing a transformer, control board, capacitor, or safety switch that isn't good.

Ventilation system maintenance

Most homes don't have a ventilation system designed with an HVAC system. You can learn more about ventilation here, but in short, the goal of ventilation is to introduce outdoor air into the home to improve indoor air quality.

When designed within an HVAC system, the home can have fresh air exchanges with the air outdoors. Depending on the ventilation system, maintenance could involve cleaning or replacing filters and ensuring that the electronics communicate with the rest of the HVAC system and that the mechanisms are working correctly.

Most homes have kitchen and bathroom ventilation regardless if there is a ventilation system designed within the HVAC system. These types of ventilation systems don't usually fall under the kinds of maintenance an HVAC pro will maintain and service, yet most pros have a good understanding and knowledge of them and could help if something is wrong with yours.

Ducting system

The ducting is a crucial component in a ducted HVAC system and should be tested and inspected during each visit. The ducting can affect the system performance and indoor air quality.

When testing and inspecting ducting, a visual inspection of the ducting ensures they are appropriately connected and clean. Next, a static pressure test on the system determines if there are restrictions within the system or if there is too little restriction in a system. A pro should always check static pressure with a clean filter. A restriction in the system could be because of a restrictive filter, a restricted indoor coil, or a sign of ducting problems. Too little restriction can indicate disconnected ducting or ducting problems.

If any ducting is disconnected, the pro may connect it on the spot or schedule a time to fix it. And if the ducts are dirty, they may suggest duct cleaning or replacing. You can learn more about our recommendations regarding ducting here.

The static pressure test clearly shows whether the ducting system is working well or if any adjustments need to be made, such as adding or removing supply or return ducts or resizing the ducting to ensure the system receives proper airflow. Proper airflow is essential for the refrigeration cycle to work correctly for air conditioning, prevents a gas furnace from overheating, and allows the motors to work under minimum strain, which can increase their lifespan and help the system run efficiently.

The HVAC pro may take this further, check that each grille (vent) receives good airflow volume and velocity, and suggest air balancing if needed.

Indoor air quality system maintenance

Each home has various indoor air quality (IAQ) solutions. The type of maintenance needed for each IAQ solution is different. Every HVAC system has an air filter; some have other indoor air quality solutions, such as UV purification, humidity control, ventilation, and reaction defense systems.

Below we will discuss what needs to be maintained for each system. We discussed ventilation maintenance in a previous section.

The air filter should be checked and replaced if needed. Just keep in mind that many of the tests done in the previous sections need to be done with a clean filter to get accurate measurements.

If there is a UV purification system, the bulb should also be checked and replaced if needed. Most manufacturers recommend the bulb be replaced every 1 to 2 years for maximum effectiveness.

The HVAC pro should check the humidity control systems as well. If a humidifier is in place, it may have a humidifier pad that should be replaced, and if it is a steam humidifier, it should be cleaned from any erosion. You can learn more about the types of humidifiers here.

Dehumidifiers extract moisture from the air via condensation and should be checked to ensure the process is working correctly, and the drain lines are unclogged.

Reactive defense systems include ionizers and PCO devices. Ionizers are usually maintenance-free, and PCO devices may need a UV bulb and another component known as the catalyst that needs to be replaced yearly.

All systems should be checked to ensure they are properly wired and communicating correctly with the rest of the HVAC system.

And finally, an indoor air quality scanning report is completed to check how effective each IAQ solution is and to make recommendations on improving other aspects of IAQ in the home.

HVAC Maintenance costs

The maintenance costs for the heating and cooling system cost vary by location and how comprehensive the maintenance service is. Each company includes various checks and services in its heating and cooling maintenance packages. To get a general idea, many companies offer promotional lowballed $79 tune-ups to "get in the door" and up-sell their services. However, comprehensive HVAC maintenance can easily cost upwards of $350.

HVAC Maintenance FAQ's

Are HVAC maintenance plans worth it?

Whether HVAC maintenance plans are worth it, depends on how much it costs and how much you are getting. Comprehensive plans that include HVAC system cleanings and system check-ups and adjustments are typically more expensive; however, they result in more efficient HVAC systems that last longer.

Always consult with an Air Pro and explore your options before committing to an HVAC maintenance plan.

What is an HVAC maintenance plan?

What are some DIY HVAC maintenance tips?

What is done during HVAC maintenance?

Can AC maintenance improve indoor air quality?


HVAC maintenance is the last thing you want to add to your yearly maintenance checklist. However, an HVAC system has many moving parts that work together like clockwork to ensure your home is comfortable and that the indoor air quality is pristine.

We covered many topics, such as the importance of HVAC maintenance and how it keeps your system working safely, efficiently, and when needed. We discussed when and how often HVAC maintenance is required and outlined what HVAC maintenance includes and what recommendations or adjustments you could expect for each part of your HVAC system.

Now that we spend more time in our home, being comfortable in it is more important than ever. And scheduling HVAC maintenance is easy. The maintenance takes 1-2 hours and requires about 10-15 minutes of your time in the beginning to show the HVAC pro where the systems are, and in the end, for the HVAC pro to present their work, findings, and recommendations. All you have to do is be home while they do the job.

You can connect with a pro to schedule HVAC maintenance, or contact us or comment below if you have any questions.