Seems like a lot of work for little benefit. You can purchase washable furnace filters for very little money, and then just rinse them out with water every couple months.
Ditto. I just buy a washable one that I rinse out from time to time. Then I don't have to worry about storing filters or material to make filters.
First, people most people seem to misunderstand the purpose of an HVAC filter. It is to protect your furnace from damage, not act as a whole-home air purifier like most people these days seem to think. The more "filtering power" or higher MERV rating, the lower actual airflow through your system. Too much and you'll take it out of the operating spec and may cause damage to the HVAC system. You want an air purifier? Go buy one, don't use your HVAC because it is one of the most expensive systems in your property to repair or replace
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Back to washable filters, most of them are a joke, anything claiming to be both electrostatic and washable simply... cannot be, from my understanding.
Relating to the situation at hand; I would rather "dispose" of a rental property's filter rather than attempt to clean it.