HVAC filters are designed to protect the equipment, ie the heat exchanger, evaporator coil and fan blades. They are not designed to help with allergies. That said if you insist on using one, get one with a high MERV rating and change it often, at least once a month maybe more often depending on your location. Failure to do so can lead to system issues. I do not recommend any specific brand just look at the MERV ratings. The Higher the number the more restrictive the filter and the smaller particles it can filter out. Just remember this can have negative consequences for your HVAC system especially if you don't keep them changed.

Other alternatives are polarized media electronic air cleaner like Dynamic Air Quality Solutions.

Cleaner Air

A lot of people working on equipment pan the Filtrete filters for being too restrictive. I’ve used them for years, with old and new equipment, and never had an issue. The old systems both failed due to conditions unrelated to airflow restriction (one was simply so old the coil wore out, the other was damage caused by an out of level pad (before I was aware of that issue). It helps massively with allergies, and if you elect to try it, start with a 1200 or so before you go crazy on a 1800+.

Change the filter immediately if:

https://www.centralacwarehouse.com/

The filter is damaged. Whether it happened inside the packaging or while being installed, a damaged filter that has bent fins, collapsed cells or holes will not work as well as an undamaged filter, especially if it allows system air to bypass the filter at any point.

The filter is damp. A filter affected by moisture intrusion, system condensation, or even high indoor humidity can quickly become moldy and spread airborne mold spores throughout the home via the ventilation system.

There is evidence of microbial growth or mold on the filter. Mold spores already infiltrating the home via the HVAC system are not only bad for the unit itself, but they can pose a health hazard for the family, ranging from an irritated respiratory system to a serious allergic reaction.

The musty smell produced by a moldy HVAC filter is also unpleasant and may take a while to completely eradicate from inside the home. If you discover that you have moldy air filter, it’s important to have the cause investigated further.