I have a Century HZD036 Geothermal unit and have been using merv 11 filters. Is it ok to use merv 13 filters in it?
A merv 13 filter will restrict airflow more than a merv 11 filter. Too much restriction puts additional strain on the equipment, which can affect efficiency and reduce the life of the equipment. Thicker filters (2" to 4") are less restrictive than 1" filters. If your ductwork is properly sized for your equipment, which is often not the case, and/or you have a 2" or thicker filter, then a merv 13 is probably ok. To know for sure, you'd need to have an HVAC tech measure the static pressure of your ductwork to see if it's low enough to accommodate a more restrictive filter. If not, you could consider installing a media filter cabinet with a thick filter, such as an AprilAire 1000 series, or an electronic air cleaner. I'm currently using merv 11 filters in my conventional and geothermal systems. On the geo system I also have the Nu-Calgon iWave-R electronic air cleaner. This seems to do a great job removing any musty basement or cooking smells. The iWave is supposed to kill bacteria, mold, and viruses and cause small particles to clump together so they are caught by the air filter. The iWave-R is small, installs in existing ductwork, and should be easier to install than a new filter cabinet.
