We finally got new Carrier AC and furnace to replace our original 26 year old still working Carrier units. Everything is working great but have a question about filters. Old furnace used 1 inch thick 16X25 filters and I used the basic cheap pleated one from Menards. New furnace, Carrier Performance 80 110BTU, has a big filter box that takes 20X25 filters. Installer put Best Air 20X25X4 Merv 8 in it but looks like it will take 20X25X5 size too.

I noticed Menards sells the Best Air, and other, brands of 20X25X4 filters. The Best Air MERV 8 is $22 and the MERV 11 is $24. Anyone have any experiences using such and have an opinion of MERV 8 VS MERV 11 as is it worth the extra couple bucks?. We do have pet birds and rabbits so I am thinking of trying the MERV 11. I understand filter airflow resistance increases as MERV rating goes up. Furnace has variable speed ECM motor so I am thinking it would not be an issue and Carrier sells and air filtration unit that they recommend using MERV 8 or 11 with. Air flow using AC currently is very impressive with new furnace and much much better than the old furnace. I plan on changing filter at least twice a year and more often if needed.

Thanks for sharing of any experiences or advice.

We are required to use MERV 11 or higher in the HAVC systems we build for our ENERGY STAR homes so it must be a good idea. Just be certain to change your filter monthly.

quote:

Originally posted by smlsig:
We are required to use MERV 11 or higher in the HAVC systems we build for our ENERGY STAR homes so it must be a good idea. Just be certain to change your filter monthly.

Thanks for the info. Do MERV 11 filters require changing more often than MERV 8 filters for the 20X25X4 inch size? Our system was installed by Carrier Factory authorized dealer with certified techs and they recommended twice a year starting point for changes.

4 inch and 5 inch are often the same. Check actual dimensions. Your furnace should notify when it needs new filter. I change mine every 6 months. To extend the life, vacuum monthly the dirty side

quote:

Originally posted by oldbill123:
4 inch and 5 inch are often the same. Check actual dimensions. Your furnace should notify when it needs new filter. I change mine every 6 months. To extend the life, vacuum monthly the dirty side

Thanks for that info. I did notice the Best Air is only 3.5 inches thick. I remember tech showing me the Honeywell Pro T4 thermostat and saying something about filter notifications. I will check that out. I already vacuumed the back side of the filter once as with the increased blower volume some big chunks of dust were in it. I will probably change the first filter pretty soon.

You don't need to change these big cartridge filters as much as the old thin ones.

My HVAC guy just put in a new Lennox system and it's got the really fat filter too, he told me to change every 6 months.

I use the Trion 20" x 25" x 5" Air Bear Cub Replacement Filter because that's what my furnace came with.



I've tried both the MERV 8 and the MERV 11. Honestly, I didn't notice any difference.

I buy them from a local plumbing A/C supply place, but SupplyHouse has them online:

https://www.supplyhouse.com/Tr...ement-Filter-MERV-11

quote:

Originally posted by PASig:
You don't need to change these big cartridge filters as much as the old thin ones.

My HVAC guy just put in a new Lennox system and it's got the really fat filter too, he told me to change every 6 months.

Thanks, that is what I was told too.

quote:

Originally posted by chellim1:
I use the Trion 20" x 25" x 5" Air Bear Cub Replacement Filter because that's what my furnace came with.



I've tried both the MERV 8 and the MERV 11. Honestly, I didn't notice any difference.

I buy them from a local plumbing A/C supply place, but SupplyHouse has them online:

https://www.supplyhouse.com/Tr...ement-Filter-MERV-11

Great info Chellim1. I think I will get a MERV 11 to try out since it is only $2 more. I can't see going any higher than MERV 11 for my situation unless there is widespread threats of anthrax terrorist attacks.