It is a good idea to hire an HVAC company, to inspect and do maintenance on your system twice a year, every Fall and Spring, like Pacific Heating & Air Conditioning. We offer services like Service and Repair, Cleaning or replace air filters, inspect and clean wiring and mechanisms of the unit, testing of pressure switches and safety controls; which is a bit more challenging for the average homeowner. One thing a homeowner can do is remove any debris like leaves, dirt and grass clippings from the unit. Also, you should trim back shrubs and other plants from around the unit to keep from impeding air flow to and from the unit.
If you are planning on purchasing a new heating or cooling unit, be sure to check the energy efficiency rating. While energy efficient units cost more initially, they will save energy and money in the long run.