The interval of filter changes would depend on several points, like the type of your home. Do not defer the change of filters for too long, as it would only depreciate the effectiveness of your machine, and would pull up the operating expenses. Again, too frequent filter changes would be a sheer wastage of money!

Remember, that if your air conditioner has an efficient filter, you would need to clean and change it all the more. Most of the people find pleated filters sufficient for them. These have an efficiency of ten to sixty percent, though some companies say that their filters are even more efficient.

The pleated filters have to be replaced once in every three to six months. You should make the replacement within three months if your locality has a high level of dust.

If you want a filter that has the maximum efficiency, go for an electrostatic, electronic or HEPA filter. These filters are more effective, and so you would have to change them more frequently.

The electrostatic filters possibly have the best blend of efficiency and value. You would initially have to pay almost two to six times more than a regular throwaway filter, but ultimately it would be more cost effective as these filters can be cleaned and recycled just by washing.

Even if the electronic filters are dirty, they do not hamper the flow of air. When they are dirty, they lose their capacity of draining dust out of the air and simply stop working properly. You would then have to clean and dry the electronic cells by soaking them in HVAC cleaner solutions.

If you are searching for the most efficient filters, HEPA filters are what you want. But the problem is that these filters become choked up very fast, can hamper the airflow and can even become unusable if too much clogged. Hence you would have to check them each month. You can ask your conditioner contractor whether your machine needs this type of filter.

Your hardware store can supply you with the more economic panel filters at ten dollars for a pack of four. But these filters rank the lowest when compared to the others. So using these wouldn't really do much good to you or your machine. The dirt will gather on the evaporator coil of your air conditioner instead, and you will have to clean the coil each year. These filters are actually so inferior in their functioning, that you shouldn't be surprised if even after one year of installing it to your conditioner, you find that its not yet dirty enough to be replaced.