Q. I’ve read a couple of articles about furnace air filters but I’m still confused about what type would be best for my heater. I’d like to remove dust, pollen, pet dander and so forth from the air in the house, but some sources say the filters that clean air best can damage my equipment. Is this true, and what type of filter do you suggest?
A. There is some controversy about this, but I think if you don’t let the filter get too dirty and change it when necessary, you shouldn’t damage your equipment no matter what type of filter you choose.
So-called high-efficiency filters, which screen out the most and finest particles, are the main targets of criticism and might cause problems with the blower motor or other mechanical parts if allowed to get so dirty they clog free movement of air through the blower.
No matter what type of filter you use, don’t rely on manufacturer’s claims about how long a filter will last – pull it out periodically and inspect it in good light. Once-a-month inspections are about the minimum for filter safety.
If necessary, hang a calendar somewhere near the heater or air conditioner and check the dates when you make inspections. It is also a good idea to print the date on the cardboard border when installing a new filter.
I tried high-efficiency filters for a while but didn’t notice much difference between the performance and that of a good-quality pleated filter, which costs a lot less. I now use pleated filters regularly.