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HVAC filters
- Thread starter factorytuned2012
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How do these work in a 1" filter frame?
Filterbuy.com
I use 3M Filtrete either 2000 or 2200 ( the premium electrostatic) the only one higher is the 2500 which has some type of app thing. USA made. I exclusively used 3M Filtrete on my last furnace and got 21 years out of it. My new furnace can't handle a dual filter setup ie Coarse pre-filter with the 3M as it is too restrictive. It's a 93% efficient model furnace. Look at the merv or filter efficiency. There are three different types of filter efficiencies listed depending on the manufacturer.
Most furnaces aren't designed for a filter thicker than 1" unless specified. My 1" filters last 90-100 days and the backside is spotless.
From the picture posted, it appeared to be kind of stepped down with a thicker part above a 1" lower section. My eyes must have deceived me on that.
There is a step and the additional 2"-3" extends up into the ducting. You have to make sure it is a "return grill" filter. My return grills have a latch that allows them to swing down and then these slide right in and out. It is much better than having to go into the attic to change the filter at the air handler.
OH I see. So my eyes weren't deceiving me. NOW, if they made that in a 2" version, I think it would work in my furnace frame. It has room for two filters (two slots) but I don't see any value in using two filter due to possible air flow restrictions.
But 2" would flow more air and hold more dirt.
I never understood the logic in that statement . Sure , as the pores stop up , less dirt gets through . Also less air . And it's harder on the system trying to pull air through a restricted filter .
Correct, you do understand.
Same as a higher MERV filter.
Incorrect.
Work by a motor is measured in amps.
The less air it moves, the less work it does and the lower the amps.
A lot of people misunderstand how that works.
If you have an ammeter, you can prove that to yourself.... or you can just trust me.......
or you can probably google it and get varying answers.
On a water pump, you can't restrict the suction side or the pump will cavitate..... so you restrict the outlet...same result, you lessen the work done and that lowers the amps.
MERV alone isn't enough to gauge the restriction of a filter. Eg 3M Filtrete 1900 (MERV 13 equivalent) has less restriction than some "no name" MERV 8 filters due to the massive surface area of the filter media.
The market is flooded with generics so try to stick with proper companies that publish specs of their filters. I'm using Camfil as my AHU uses an odd size (20x24) and Camfil filters are reasonably priced and readily available in my area. Currently using Farr 30/30 (MERV 8) but will try their AP11 (MERV 11) next as it has the same static pressure as the Farr 30/30.
The market is flooded with generics so try to stick with proper companies that publish specs of their filters. I'm using Camfil as my AHU uses an odd size (20x24) and Camfil filters are reasonably priced and readily available in my area. Currently using Farr 30/30 (MERV 8) but will try their AP11 (MERV 11) next as it has the same static pressure as the Farr 30/30.
recognized name brand MERV 10 to 11, (13) at the most, preferably carbon infused, also duct cleaning every few years is a good idea,espicially if you have pets..to high of a merv rating can be more restrictive as filter loads up if not changed correctly, thus making the fan moter work harder and possibly shortening the motor life. install a magnehelic to measure restriction accros the filter can be a thought.
Incorrect.
Less air means the motor does less work.
Less work means lower amps.
Lower amps will not shorten motor life.
I've been dealing with construction in the house most of the spring and all summer. I used up a 4 pack of the super cheapo green glass ones just to save a buck because I'm changing them so often and those made me really want to back away from the higher MERV rated ones that I thought were epic. So this weekend I picked up a 4 pack (or is it 3, I can't remember) of the lower MERV HDX at Home Depot. I hadn't realized just how much I was choking my system by using "better" filters. I had one of the high MERV left after I'd used up all of the green cheapies and just putting it in I could feel the system stall like when Mad Max turned off his blower in the Interceptor.
I used to buy those "better" filters too until our furnace quit working one winter. All that was wrong was a limit switch and the HVAC said the heavy filters can restrict the airflow too much and cause that. He recommended using the inexpensive filters and change them monthly. I trust his knowledge....
I said " The system " , I didn't say " the motor " . The system is trying to cool the house . The efficiency of " the system " is reduced because it's not moving air over the coils . It's having to run longer as well . I can see where you could misunderstand what I meant .
seems like more resistance over the filter will create more work for the fan/motor and air flow,,,sorry i worked with hvac in a large hospital for over 30 years,but always looking to learn something new.
No need to get your feelings hurt.
The "motor" is the same for heat or cool.
It is the only part moving air.
If you are letting it get so dirty it affects the cooling of your house, you may have other issues.
A lot of people misunderstand this.
How hard a motor works is measured in amps.
If you restrict the amount of air it can move, it pulls less amps....unless you have motor control that tries to speed up the motor.
Most home systems don't.
The easy way to confirm what I am saying is to take an ammeter and read it as normal with all doors closed and the filter in place.
Then remove a side panel that will allow the fan to pull as much air as it wants.
Amps will go up.
Or, put an ammeter on a pump lead.
Open the valve on the head side of the pump allowing it to pump max amount.
Amps will go up as more work is done.
Close the valve and amps will drop as less work is done.
If you restrict how much work is being done, amps go down.
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