furnace filters

[Asian_defender]

I buy these guys when they go on sale (which they are right now)
https://www.amazon.ca/gp/product/B00...?ie=UTF8&psc=1

Just remember to change them often, I do mine every 2 months and haven't noticed any airflow restrictions

[sabad66]

for my furnace with the a/c coil i use cheap fibreglass to get maximum airflow. For my other furnace i use a pleated, but lowest MERV rating (8), again for better airflow but still get some filtration going on. Fibreglass i change monthly, pleated every 2 months.

If i had new furnaces with powerful fans i'd probably go with a bit higher MERV rating.

I just started using this company for pleated.
www.purefilters.ca

I got a 10 pack of 16x25x1 merv 8 pleated filters for like $70 or so. For the fibreglass i get them from Home Depot since they are like $5.