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A/C tech says I should be using lower quality fiberglass air filters?


bluesbreaker's Avatar
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09-12-17, 04:31 PM   #1 (permalink)  
A/C tech says I should be using lower quality fiberglass air filters?

I had a free maintenance check done on my Carrier 3.5 ton split unit central heating and A/C system (electric) this morning. My house uses one air filter. The tech says I am using incompatible air filters. I use Filtrete basic filters with the pleats. He says I should be using those cheap fiberglass weave filters which almost look like green woven hairs

Really? I haven't used those cheap fiberglass weave filters in many years. The cheap filters don't filter as many particulates. The tech says the pleated ones obstruct air flow and make the system work harder. I don't know. I thought I was doing the right thing using the pleated filters which remove more particles and dust. Do you agree with him? Can I at least use up the last two pleated filters?

He also advised me not to use the one time purchase filters that you clean and re-use

 
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09-12-17, 06:26 PM   #2 (permalink)  
A filter is given a MERV (minimum efficiency reporting value) that denote how well it filters. The higher the number the better the filtering but the more resistance it adds to the airflow. Usually 7-12 MERV filters are used in a home system. I believe fiberglass filters fall in the 1-6 MERV area.

You could ask your service guy what value filters to use in your Carrier system. Do a search for MERV.... there will be much to read.


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09-12-17, 06:44 PM   #3 (permalink)  
See my post #6 here.

http://www.doityourself.com/forum/ai...er-really.html

 
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09-12-17, 09:57 PM   #4 (permalink)  
I read Norm's entire posting. The 3M Filtrete filters I have been using are MERV 5. I'm not sure I agree with fiberglass weave filters since Arizona has higher dust accumulation in the houses. Maybe a lower MERV pleated filter is the way to go, if they even sell them around here.

I'll do some reading and ask another tech at the HVAC company. I had a system replacement done earlier this year.

 
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09-12-17, 11:36 PM   #5 (permalink)  
5 is pretty low. I use the Rheem (HD house brand apparently) and they use FPR (Filter Performance Rating) not MERV. Look like similar and comparable values. I use the FPR 4 which is probably about like your MERV 5. (Pleated, reinforced, pollen, dust, pet hair, etc) Did the same on my house in VA (16 yrs), my other house here (8 yrs), and my place now (2 1/2 yrs). Never had an airflow related problem and all 3 homes had/have original A/C units from 1990.

My filters are something like $7.50 for a pack of 3?


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09-13-17, 12:05 AM   #6 (permalink)  
Hey Vic,

I was hoping you would weigh in with your opinion since you live in Kingman. That tech was taking comparison readings with pleated filter or NO filter in the grill. How accurate is that? I'm not crazy about using the cheapo woven fiberglass things. I'll go to Lowes/Home Depot tomorrow and see what else they have. Thanks all.

 
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09-13-17, 01:04 AM   #7 (permalink)  
From a technical standpoint - Your indoor blower motor is rated to operate at or below a certain amperage reading. And the HVAC tech inspects this when he inspects your HVAC system. Once it begins to exceed this rated amp draw specification (it's listed on the motor), it will heat up and malfunction sooner than a motor that is operating at or below its rated specifications. You're system is also designed to operate at a specific static pressure (inchs of water column) which the tech may have or may not have checked, probably not.

Many things affect the static pressure and amp draw, including the air filter, the duct work, the speed of the motor, how clogged the air filter is, the vents, ect. The main thing to do is grab the amp draw off the motor, if it's below specs with your pleated air filter in the way, your motor is not exerting itself. If you're pleated air filter happens to be the one restriction (technically, everything is a restriction on the air, even the size of the duct) and by removing it or replacing it with a poly filter instead of a pleated filter, then he's correct. This applies to the static pressure as well.

It's probably not an issue. I always tell people to run whatever they feel like spending their money on when it comes to their homes, the 1 inch thick residential air filters are not going to be the different between life and death when it comes to IAQ, either is the 4 inch media filters... Home's are not designed to provide IAQ benefits like say, hospital operating rooms, and lithography silicon chip printing rooms where these rooms are filtered at 12 inchs and more.. But my point isn't to point out the difference in size in air filter methods, because it's not even about the filters until the room is designed to be filtered =). 1 inch filters are designed to be marketable and the main point of these air filters is and should be to keep your evaporator coil clean, not your air.

 
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09-13-17, 06:22 AM   #8 (permalink)  
adamsairhouston,

Best explanation I have ever seen. Kudos to you.

The main thing to do is grab the amp draw off the motor, if it's below specs with your pleated air filter in the way, your motor is not exerting itself.
Love your third paragraph. Puts things in perspective.

these air filters is and should be to keep your evaporator coil clean, not your air.
Very good point.

 
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09-13-17, 07:59 AM   #9 (permalink)  
But my point isn't to point out the difference in size in air filter methods, because it's not even about the filters until the room is designed to be filtered

And, remember the filter only works when the unit is running, add up the minutes per day it runs and you will see that regardless of the filter used, it just doesn't have the chance to do much!

 
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09-13-17, 08:33 AM   #10 (permalink)  
Another good point by Marq.

So what is the purpose of an air filter? Not to filter the air you breath or live in but to protect the evaporator, motor and inter components.

We have just demolished the the whole concept and marketing scheme of Filtret, American Air Filter and others. But I guaranty, present this argument to the general public or the furnace/ac installers (who have an agreement with mfg and filter mfg's to sell their product) and it won't fly. People will believe what they want. Just tell them what they want to hear.

I'm betting Aadamsairhouston is the exception to the industry rule, if he is an installer,

 
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09-13-17, 12:16 PM   #11 (permalink)  
I talked to another tech at the A/C installer today. He agreed with the other tech that I should start using the cheap poly/fiberglass weave filters. I'll guess I'll use up the last two pleated ones and switch over. Unless I can find a low MERV pleated one at Lowes which I doubt.

 
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09-13-17, 02:34 PM   #12 (permalink)  
Well, I will still use what I've been using for over 20 yrs. Basically it's one step above the woven blue/green ones. I realize it's basically to keep the evap and returns cleaner, so if it grabs a bit more, it must be working, right? Actually had a tech say he hadn't seen such a clean system (inside and out, cause I also cleaned out my evap and condenser, straightened fins, fixed rusty spots, etc) with that many years on it. That was the one in VA I'd had since new.


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09-13-17, 03:16 PM   #13 (permalink)  
Yeah, I've been using the pleated reinforced ones for many years also. Whenever I cleaned the indoors attic air handler unit and coil, there is virtually nothing to clean out. But I spray with solvent or whatever anyway.

Maybe this place I hired had complaints about burned out blower motors.

(Left tailgate down on truck while cycling garage door. So I am getting new garage door assembly installed as we speak.....................expensive mistake even if I did get 22 years out of old door)

 
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09-13-17, 09:29 PM   #14 (permalink)  
By the way, thanks also for the detailed explanation regarding the amp draw off the blower motor. Gives me some insight on why the A/C tech is fixated on the nested fiberglass filter. I still don't like the idea of using those. I'll try them out for awhile and then see how dirty the insides of the units are. If I don't like what I find, I'll go back to pleated.

 
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