Use a pleated filter and keep it clean. Unless you have allergies or breathing problems, the cheapest pleated filter is perfectly fine. The cheap fiberglass filters that you can see through let larger particles through to clog up your indoor coil. Also, just because a filter says it lasts 3-6 months does not mean that it will last that long in your environment. Check your filter often at first to gauge how long yours will last. Dirty filters or coils can cause the A/C to run less efficiently and even to ice up and stop working in extreme cases. Another problem with the indoor coil that you can check when you are replacing your filter is the condensation drain. It is a good idea to pour a ½-1 cup of bleach down the line to stop the growth of algae and to keep the line from getting clogged and overflowing all over your ceiling or closet or rotting out the emergency drain pan.
Wash the outside unit with water. Take the garden hose and a sprayer or just use your thumb over the end to increase the water pressure to clean the coils. Some units have fins over the coils, just angle the water so it will pass through. This is perfectly safe to do while the unit is running. In fact, if you hear the water hitting the fan blades, you know you are getting completely through the coil. You will get wet doing this, but it’s a hot day, right?
Check the temperature of your attic. Ideally, it should be no more than 10 degrees above the outside temperature. Radiant heat barriers are all the rage right now, but they can be expensive to install. You can do other things first that are much less expensive. You can check your soffit vents and replace them if they are clogged (approx. $1 ea). Air needs to be able to circulate through the attic and the soffit vents allow air to come in under the roof and rise to the top of the attic where there should already be some type of ventilation. A ventilation cap would be the minimum to let the hot air escape, followed by turbine vents for passive ventilation. Some houses have gable-end vents but it seems they aren’t used that much anymore. For active ventilation, you can install power ventilators and they do have solar-powered and electrical models.
Keep the A/C serviced and adjust the Freon levels if needed. Freon doesn’t wear out, but it does leak out in many cases and low Freon can cause the A/C to freeze up and stop working.
If the A/C unit is more than 10 years old, consider replacing it for a more efficient unit.
Any device, whether it is car or AC, has to be replaced after a period of 8 to 10 years as the model is quite old to sustain for a long time and the fact that it has come this far is too much in itself so consider purchasing the Best San Diego AC in town as this is the perfect time.