Filters, one of the most expensive category for maintaining your system is your filter. How to choose it. We must look at two factors,restriction of air flow and filter efficiency.
Calgary filters
MERV 4 Efficiency <20% Polen, Dust, Particle Size >10pm Minimal filtration
Filter merv 8
MERV 8 Efficiency 30-35% Mold, Hair Spray Cement Dust Particle Size 3.0-10.0 pm
Filter Merv 11
MERV 11 Efficiency 60-65% Legionella, Humidifier dust Milled Flour, welding fumes Better  filtration
Merv 16
MERV 16 Efficiency >95% All Bacteria, Tabaco smoke Superior filtration Particle Size .30-1.0 pm


Is important to keep it clean,  to have less restriction and to protect your blower motor and to keep your indoor air clean. Dirty filters will have more resistence on air flow and the blower motor will overheat. As a result after long period of time, blower motor can broke early.

FiltersHEPA Filtration system is high efficiency system up to 99.97%. Is designed for removing particles and bioaerosols down to 0.3 micron. Particle like virus, carbon dust, combustion smoke. HEPA system it is a sealed bypass design which traps particles and prevents them from escaping.