Carrier Oil Furnace Filters

[Zee09]

Changed out the filters in my mothers oil Furnace.
Its about 7 years old and has been problem free
I use lower # Merv rated filters.
The question.

This furnace has two filters- one lies horizontal and another directly over top of it is slanted vertically.

Is there any air restriction from them using a double filter system? ( 16 x20 filters)
The double unit is new to me. This is a single system and a large 3 story house.

 

[doitmyself]

If your configuration results in the filters being "stacked" (same air forced to pass through both filters), then your are correct that it will increase the restriction to flow. Two 2 inch pleated filters stacked will have more restriction than a single 4 inch pleated filter. If the filters are in a V shape that simply enlarges the square inches of filter area, then no, it does not result in increased restriction.

Google stacked air filters for numerous responses: https://hvac-talk.com/vbb/showthread.php?1780751-Stacking-Two-2-quot-Filters

In the picture below, if the air was passing up and down through all filters, there would be huge restriction. In this case it passes from side to side without increased restriction - it just has a huge amount of surface area.

... http://www.home-air-purifier-expert.com/whole-house-air-purifiers.html

 

[Zee09]

Thank you very much. That is the system but only two filters.