Good tip!Try washable metal mesh furnace filters. Easy to clean and if your paper filters run around $10 they will pay for them selves in 3-4 changes and they last essentially forever. Sounds like you're in good shape as long as you have power.
If any good with metal fabrication, can make own reusable furnace filter frames out of aluminum or sheet metal. Many washable open pore fabrics and foam can be used for filter materials. Just make sure to construct filter assembly so blower or fan doesn't suck filter medium used into furnace/HVAC system.
Are also washable, reusable and scissor cut to size filters available like stiff fibrous "Hogshair" filters. As a side note: The Hogshair filters need no frame. Simply cut to size and use.