We have all heard the old adage – If it ain’t broke, don’t fix it! While in many cases this is great advice, when it comes to ensuring you get the maximum life and efficiency of your HVAC system, there are some components that do need periodic servicing. Let’s discuss the main components of a typical residential HVAC system and highlight what components require periodic replacement due to normal usage and what components need to be maintained in order to prevent significant expenditures and repairs down the road. Once a homeowner understands some of the basics of their system, they can be better informed on making decisions regarding how to best maintain their HVAC system by either doing some parts of the maintenance themselves or by using a professional and knowing what to expect from their HVAC service company/technician.

  1. Output Temps from the System. When in A/C mode, most systems will have approximately an 18-20 degree temperature difference from the supply air coming out of the registers vs. air entering the return grill at the filter. Things that can impact the temperature levels could be air flow (a dirty filter, leaky duct systems, improperly designed duct system, a dirty indoor coil, etc.) or the unit may need additional Freon added (or removed if it was over charged previously). Just because your system is not heating or cooling does not automatically mean it needs to have additional Freon put into the system. You should never instruct an HVAC tech to “just charge it up” or get upset with a service tech that tells you that you do not need additional Freon added to your system.
  2. Indoor Air Handler Coil. The primary job of the air filter is to keep this coil from getting dirty. Periodically inspecting the coil and ensuring it is clean is critical. Even if you change your filters regularly, a coil can get dirty if part of the duct system fails and allows unfiltered air to enter your system…and finding this out many months or years later will have resulted in wasted energy cost, and a reduction in the life of your HVAC systems. A part of any periodic maintenance inspection must include visually inspecting the indoor coil! Even if you have a new home and HVAC unit, it should be inspected. Recently we found an indoor coil that was approximately 30% blocked due to the original installers leaving some of the manufacturer’s paperwork inside the coil housing which got sucked up to the side of the coil. Also systems in new homes sometimes get run while dry wall finishing/sanding is occurring. These fine dust particals will get past filters and clog up an indoor coil. This is one of the main reasons why the HVAC systems in brand new homes don’t last as long as replacement systems. Some HVAC systems may develop a “dirty sock” smell to them as a result of a dirty coil. It is much more cost efficient to take steps to keep the coil clean on the front end of a problem vs. remedying the problem after the fact with duct cleaning, UV lights, or “air scrubbing” equipment, or having to replace the entire duct system.
  3. Condensation Line Cleaning. All A/C systems and high efficiency gas furnaces will generate condensation, and this water drains out of the system via a gravity feed drain line or a condensation pump. All drain systems will generate crud in them over time (the amount of crud build up increases when dust gets into the duct system) and eventually a clogged drain will occur. Homeowners with indoor air handlers in the attic need to ensure they have safety switches to shut off the system should a condensation line back up occur and a suitable sized drain pain to catch any overflows. We have seen instances of a ceiling collapse due to a simple drain line being clogged up and nobody realizing it for months! At the very least, a homeowner should use a shop vac and suck out the condensation drain line each Spring if they are not having their system professionally inspected/maintained, or ensure the condensation pump is properly discharging water to an area outside the home.
  4. Superheat or Subcooling Levels. Special equipment is needed to obtain this info which is required to properly charge the system. Although it is helpful to have both pieces of information, systems manufacturers recommend charging by only one method and the technician must first determine if the indoor air handler has a TXV value or Capitulary tube on the indoor coil to meter the Freon. Be wary of any technician who adds Freon without first identifying what type of Freon metering system is on the indoor coil!
  5. Electrical Components. All traditional HVAC systems have fan motors that contain bearings. Although modern motors have “lifetime sealed bearings,” they will eventually dry up and create additional friction resulting in a many motors lasting about 10.5–12 years….just past the 10-year warranty period that most manufacturers currently offer. Most of these bearings can be oiled to extend their expected lifespan. If you are not using Comfort Keepers HVAC to do your periodic maintenance, ask your HVAC service technician if they provide this service vs. hoping the motor wears out and needs to be replaced. (The motors don’t need oiling every year, but do need to be checked by at least 5-7 years of age and checked every few years thereafter.) Most fan motors also have external capacitors and they eventually do wear out. The UF rating of the capacitors should be checked and replaced before they become too weak to start the motors. The main contactor on your outdoor system also will wear out over time and typically needs replacing every 7 years on a heat pump depending on how often the system is used and cycled on and off.
  6. Outdoor Coil. The outside unit needs to have sufficient airflow across the condensation coil similar to what was discussed in point #2. Units placed in a corner or that have bushes/fencing and weeds growing around them will have reduced airflow through the coil. Homeowners can significantly help keep this coil clean by rinsing it down with a low pressure stream of water at the first sign of dirt/dust or grass clippings build up.

Although some homeowners may have the skills to periodically inspect/clean the outdoor coil, indoor coil, condensation lines or do some of the electrical component maintenance, it is often best to have a qualified technician to periodically maintain your HVAC system to reduce emergency repairs and reduce your overall operating cost. Hopefully by understanding a few of the components that need periodic maintenance and inspection, you will be enabled to make better decisions to keep your HVAC system operating at peak efficiency and longevity.


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