Maintenance Tips

HVAC Maintenance Tips For Residential Customers

Here's a little shop talk that can help you protect and maximize your investment in environmental control.

Routine Maintenance :

These are tasks that you or your AC/Heating serviceman should perform on a regular basis to ensure the proper and efficient operation of your environmental control system. Some routine maintenance may be required to protect the manufacturer's warranty, or extended warranty. But, more importantly, these will help protect your investment by extending the useful life of your system.


Regularly changing the filters is probably the most important thing you can do to increase the efficiency and prolong the life of your air-conditioning/heating system. Filters should be changed before they become noticeably dirty. In most cases, filters should be changed monthly. But, more frequent changes may be necessary in dusty conditions, or where the system runs for long periods.

As filters collect dust, pet hair, etc. several things happen:

  • Air flow across the filter will decrease.
  • The air handler will have to work harder as it tries to move the same volume of air. That can shorten the life of motors and bearings.
  • More outside (make-up) air and less inside (room) air will be pulled across the cooling coil or heat exchanger, forcing the system to run longer to reach the desired temperature.
  • Circulating less room air across the cooling coil results in higher inside humidity, increasing the possibility of mold and mildew growth.

Duct Work:

Ductwork is a potential source of energy loss. Whether your system's ductwork is in the attic, or below the house, you should check it for damage.
Likely types of damage are:

  • punctures or tears in flexible duct or duct board allowing conditioned air to escape;
  • broken joints in all types of duct, causing large loss of conditioned air;
  • damaged or deteriorated insulation on sheet metal or flex duct, which can allow condensation to form, potentially damaging surrounding sheet rock;
  •  flex duct crushed by objects stored in attic, restricting air flow to services areas.

Older mechanical thermostats often use mercury switches. It is important that these thermostats be checked to make sure they are level and mounted firmly. A tilted thermostat could cause the AC/Heater to short-cycle or not shut off.
Programmable or Set-back thermostats usually require batteries, rather than pulling power from the system. These batteries should be replaced every year to assure proper operation of the thermostat.


Commonly called the "outside unit", this is the part of the AC system that exhausts the heat that has been extracted from the living space. It contains the compressor, which compresses the refrigerant; coils, which allow the heat from the refrigerant to be dissipated to the outside air; one or more fans to force air across the coils; and various control components.

To achieve maximum efficiency and proper operation of the condenser:

  • clear debris, such as leaves, from the air intake and exhaust areas,
  • make sure that plants and shrubs are far enough from unit to allow air flow;
  • check for dirt and corrosion on cooling fins;
  • inspect fan and fan mounting bracket for damage;
  • make sure that fan turns freely and quietly;
  • lubricate fan as required by manufacturer.

Air Handler:

The Air Handler is the part of your system that moves conditioned air throughout your living area. The unit contains the blower and motor, and the evaporator coils which chill the air. If the system is also used for heating, the air handler will have electric heat strips. Every year, in Houston, there are


If your system contains a gas furnace, you should have a licensed, professional HVAC technician inspect your system annually. A cracked heat exchanger can introduce deadly carbon monoxide (CO) into your living area.