Furnace Filter

[KevinMalone]

I personally run Camfil 30/30 MERV8 all year and change every 2500 hrs of run time, which is fortunately tracked by the air handler controller. Camfil filters are very reasonably priced online and the publish full technical specifications, I presume because they are meant for commercial applications.

I'm thinking of running Camfil's AP11 MERV11 filter once I deplete my MERV8 inventory. The MERV11 has a larger filter media resulting in the same static pressure as the MERV8 filter, and each MERV11 filter only costs $2-3 more. Might as well have higher filter efficiency if there's no performance loss, unless I am overlooking something?

Also, my AHU controller failed to notify me to change the filter after 2500 hrs, resulting in an overloaded filter. Looking at my service records, 2500 hrs of run time seemed to coincide with 6 months, so I think I'll just replace the filter every 6 months instead of relying on the controller. Question is, which months?

Heating degree days:

Cooling degree days:

I was thinking of a new filter in June for the brief cooling season and the start of the heating season, and then a fresh filter in December for the rest of the heating season.

 

[Cropduster172]

Merv 8s from Home Depot...HDX brand. I used to use the spun fiberglass ones in Summer running the AC. Worked fine and the system lasted 24 years. New single stage Bryant gas and AC 2 years ago so the HD Merv 8s changed every 2-3 months.

 

[alarmguy]

I'm thinking of running Camfil's AP11 MERV11 filter once I deplete my MERV8 inventory. The MERV11 has a larger filter media resulting in the same static pressure as the MERV8 filter, and each MERV11 filter only costs $2-3 more. Might as well have higher filter efficiency if there's no performance loss, unless I am overlooking something?

Also, my AHU controller failed to notify me to change the filter after 2500 hrs, resulting in an overloaded filter. Looking at my service records, 2500 hrs of run time seemed to coincide with 6 months, so I think I'll just replace the filter every 6 months instead of relying on the controller. Question is, which months?

Heating degree days:
View attachment 227693

Cooling degree days:
View attachment 227694

I was thinking of a new filter in June for the brief cooling season and the start of the heating season, and then a fresh filter in December for the rest of the heating season.

Good post, and I agree with your thinking. With that said it's almost impossible for many to find actual stats on filters as you have. (though you just gave me a name )
I tend to use both depending on price and many times I will use a Merv 8 on the main filter and 11 on the smaller 14x14 secondary filter in the master BR. Also sometimes the other way around.

Anyway, I do wonder even if out of the box the additional surface area prevents any performance loss what happens after it is in use?
Does the high efficiency filter clog up more readily? Not sure if I am making sense, just a thought. I use both but would never go any higher than that of 11

Im having trouble finding a source, jsut searched briefly and saw some photos on eBay, wow they do look like a nicely made filter.
I need return grill filters, Im just seeing box filters.

BTW in the past I used to buy 4 and 5 inch return grill filters but back to 1 inch and changing more frequently. It became a challenge finding the thick return filters at reasonable cost

 

[Donald]

If you want a really good filter get an Aprilaire media cabinet that holds a filter that is 5" or 6" in depth. It's $75 to replace the filter.

 

[KevinMalone]

I'm thinking of running Camfil's AP11 MERV11 filter once I deplete my MERV8 inventory. The MERV11 has a larger filter media resulting in the same static pressure as the MERV8 filter, and each MERV11 filter only costs $2-3 more. Might as well have higher filter efficiency if there's no performance loss, unless I am overlooking something?

Also, my AHU controller failed to notify me to change the filter after 2500 hrs, resulting in an overloaded filter. Looking at my service records, 2500 hrs of run time seemed to coincide with 6 months, so I think I'll just replace the filter every 6 months instead of relying on the controller. Question is, which months?

Heating degree days:
View attachment 227693

Cooling degree days:
View attachment 227694

I was thinking of a new filter in June for the brief cooling season and the start of the heating season, and then a fresh filter in December for the rest of the heating season.

With heating season coming, I tried to determine a service interval based on usage. I decided to add up the heating and cooling degree days as an estimate of how much my air handler's fan will be used, and tried to split the year up so that each filter sees ~50% usage. Does this logic make sense, or am I overlooking something?