I remember watching one ask this old house and rich showed up to a home where one of the owners had allergies. They had a forced air system and he installed this one unit on the side of the forced air furnance and it was a dust zapper you could actually hear it zap the dust with like electricity or something and he said all you have to do is once a month pull it out and run it through the diswasher. Have you ever installed one of those before. Its called a electronic air cleaner manuf. by american standard. Zaps particles 100times smaller than a regular filter.