Fitting the air cleaner to the current duct work can be a primary consideration. Not recommended is using a small F300 for a large house. The F300 are sized large, medium and small. The F300A2012 is an uncommon half size used in custom designs.
The large F300E1035 (2000 cfm) are sized for a large house with a single large heating and or AC system. The F300E1019 F300E1027 (1400 cfm) fit a medium size house. The F300E1001 (1200 cfm) fit a condo or small house.
Running the furnace-AC blower on constant is recommended. Most thermostats have an Auto-On switch. Setting the switch to ON will keep the blower running and purifying the air. The more dust collected by the air cleaner results in less dust on the furniture.
The F300 has an air resistance similar to the standard 1" filter. Thus an F300 of the same size as the heating systems 1" filter is a good reference. Review the F300 installation instructions.
Shown below, Bel-Aire adds gray foam packing to the F300. Honeywell packages the F300's for upright shipping on a pallet. When shipped by Fedex or UPS, the F300 is laid flat and other packages are stacked on top.
When laid flat the Honeywell packing has insufficient surface area. The F300 frame easily crushes down the packing and the F300 is loose in the box. Then the F300 frame and cells are subject to twisting and being pushed out of square.
We have die cut foam custom made for the F300. The foam will support the F300 when laid flat. The firm foam also adds the strength to support any other packages being stacked on top.