Hi, I have a 4-year-old Lennox HVAC system that takes these beefy 5 x 16 x 25 pleated media filters. They are MERV 10 and I usually buy these ones: http://www.filter-outlet.com/product.php?product=172475. Thing is, they're pretty expensive ($30 each is the best price I've found anywhere, usually more like $40+) and I'd like to upgrade to a reusable filter, possibly electrostatic.

I don't really know much about these filters though, and I don't want to screw up my HVAC. I found a bunch of options on ebay for custom-made filters, but it's hard to know what's junk and what isn't. I also read that when you switch from a media filter to an electrostatic/reusable one, the max depth is 2 inches.

In case it matters, my house is old but mostly remodeled and has floor returns and registers near the ceiling.

So my questions are:

1. Is it true that reusable filters are max 2" deep?
2. Do I need electrostatic? What's the benefit?
3. How do I pick a quality filter?
4. Is it ok for me to switch to a reusable filter?

Any other info would be greatly appreciated.

Thank you!