Maintenance Tips for Old AC Units

Residing in Arizona means you’re familiar with the daily summer temperatures exceeding 100 degrees. These triple-degree temperatures can put significant strain on older AC units. Some homeowners may attempt to limit their air conditioner usage to reduce stress on their units, but this can become difficult during the sweltering heat. In an attempt to cut down energy bills during the summer months, some homeowners may even overlook routine A/C maintenance.

However, skipping maintenance can be an expensive mistake. Even older AC units can perform significantly better with professional maintenance from HVAC pros in Phoenix like Chas Roberts. Regular maintenance helps to keep your unit in optimal condition. Know these tips for maintaining an older AC unit and signs of when to replace your air conditioning system.

How to Maintain an Old AC Unit

Air conditioners are a significant financial investment, and we need them to run well for as long as possible. To keep your old AC unit running smoothly, we recommend changing your filters, scheduling routine maintenance, and ensuring your air ducts are clean.

Change Filters

Dirt and dust in your filters can cause your AC unit to become less efficient over time, so replacing them every month is important. Not only will the dirty filters result in a less efficient unit, but the air quality in your home will worsen. To keep your family safe from harmful pollutants, consider changing your air filters to ones with a MERV rating of 6 or higher. New filters will keep your loved one safe from pollutants and help ease the demand  on your system.

Routine Maintenance

Regular maintenance is crucial for every HVAC system, regardless of age. However, older AC units are more prone to breakdowns, making it that much more important to have scheduled routine maintenance.

A maintenance visit from Chas Roberts includes a 26-point maintenance check to inspect the inside and outside of your unit to ensure it operates efficiently. We also offer maintenance agreement plans that provide you with regular system upkeep. With this plan, you’ll receive:

  • Complimentary plumbing inspection (plumbing not offered in Tucson currently)
  • Increase system efficiency
  • Transferrable agreement to new homeowner (if needed)
  • Priority service
  • 24-hour emergency response time
  • No overtime rates
  • Cost savings
  • 10% discount on repairs

Clean Air Ducts

Over time, dirt, dust, and other debris can accumulate inside the ductwork, reducing the efficiency of the system and degrading indoor air quality. This can be especially problematic for older systems, which may already operate less efficiently due to wear and tear. By cleaning the air ducts, you can help remove built-up debris and improve the air flow through the system, which can help it operate more effectively and reduce the workload on other components.

Additionally, clean air ducts help reduce the risk of mold and other contaminants that can pose health hazards. Regular maintenance, including cleaning the air ducts, can help extend the life of an older HVAC system and ensure it’s operating safely and working for years to come.

Signs that Indicate It’s Time to Replace your Old AC Unit

Regular maintenance and minimizing unnecessary strain on your air conditioner can prolong its lifespan, but eventually, an older unit will require replacement. Know these signs that could indicate your older unit is on its way out:

Increased Utility Bills

A significant proportion of your energy expenses are attributed to cooling your home. However, if you’ve noticed a sudden surge in your energy bill, it may be due to an inefficient air conditioning system. To ensure that the AC system is the cause of your high energy bills, it is recommended to conduct a home energy audit. This audit will help determine whether the problem is due to inadequate insulation, air leaks, or the outdated AC system. If your old AC system is the root of the problem,  consider replacement.

Uneven Cooling

Have you noticed that certain areas of your home feel colder than others? If so, this could signal that your old AC system is no longer operating as effectively as it used to. Uneven temperatures aren’t always an indication of a faulty AC system but should be taken seriously. It is possible that the airflow into your home is obstructed and it may be time to consider installing a new unit.

Constant Repairs

If you regularly call a technician to fix your outdated AC system, you may need more than another repair.  Although all household appliances require periodic maintenance and attention, your AC system should not require frequent repairs. Over time, the replacements can add up resulting in much higher costs than a new unit. As a rule of thumb, if the repairs cost more than half the price of a new unit, replace your unit.

Unusual Noises

If you have heard loud or unusual noises coming from your AC, this could indicate a blockage from dust and debris. Alternatively, this could also indicate that your compressor is defective, and the motor may need to be inspected by a professional HVAC expert. In most cases, these issues can be easily resolved through routine maintenance. However, if your AC system has surpassed the average lifespan of 15 years, the issue may be too severe for a repair, and replacing the AC system may be the best solution.

Unusual Odors

If you smell an unusual or concerning odor coming from your AC unit, such as a musty, moldy, or even burning smell, it is essential to have an HVAC technician inspect it. These issues could be the result of mold growth in the drip pan, clogged air filters, or evaporator coils. To avoid such situations, we recommend scheduling an AC maintenance service at least twice a year to identify and resolve any issues before they cause significant damage to the system. A Chas Roberts technician can help you determine whether repair or replacement is the best course of action.

Requires Freon R-22

To cool the air inside a house, A/C systems typically rely on a refrigerant gas. Older HVAC systems used a refrigerant known as R-22, also referred to as Freon. This refrigerant contains ozone-depleting substances that pose a threat to the environment. To address this environmental issue, the Environmental Protection Agency has mandated the use of eco-friendly refrigerants in new AC models. Therefore, it is recommended that you check the model of your AC system to see if it still employs R-22. If it does, consider replacing your unit with a more environmentally friendly unit that will also help you save on your utility bills.


If well maintained and taken care of, older AC units can keep you and your loved ones comfortable for years to come.

Consult an experienced Chas Roberts HVAC professional to schedule your next maintenance appointment and prepare your system  for the summer.

Family-owned and operated Chas Roberts is the largest HVAC company in Arizona and has been in business for over 75 years. Contact us for affordable, reliable service.