Multiple HVAC return air filters

[Vdawg]

Hi, We are in the process of having a new (production) home built in a subdivision here (central FL). The community has a Facebook page where a discussion started recently among homeowners regarding the use of more than one air return filter in the same system. More specifically, one at the ceiling return air grille, and a second filter inside the actual air handler. In my current 2013 home and in prior homes (all forced A/C with heat pump in FL), I have always just used one filter at the air return grille in the ceiling, although my current home does have a spot for one inside the air handler and our local technician who came out to do some regular maintenance did open it up to see if there was a filter in there. There wasn't and he did not suggest installing an additional one there.

At the time I didn't ask him about having multiple filters, but after reading this recent discussion online, it made me wonder if it was indeed possible, and also advisable, to have more than one filter installed at different locations in the same system. I have read/heard both arguments that extra filtration (or even just a smaller-micron filter medium) can put a strain on the air handler. I also read that the typical squirrel cage blower actually works *less* with restricted air inflow.

So, while I'm not trying to start a debate, I'm just wondering if there is a general concensus among experts: Do some residential A/C systems actually use two return filters at the same time (one at the grille and one in the air handler)?

Thanks!

 

[Fitter30]

Some furnaces have a inside filter that has either a clip or a spring wire to hold it in. If all the duct work was sealed there still can be some leakage even around the cardboard frame filter. Good pleated filter is all that is necessary. The only way to catch more and finer particles is a electronic air filter, running the blower 24/7 and then your not cleaning all the air. Take a vacuum cleaner it only picks up dirt what it sees. Not 6" away or a foot. Fill a room with smoke turn system on some air will get picked up right away, down low, in corners not so much. Then lets look at infiltration ( how tight the house is) only way is to have a blower door test done. New house should be done before insulation is installed if is batt type or right after foam so almost every air leak is caught and sealed. Then a hrv or erv unit is used for fresh air.

 

[Sponsor]

 

[Breplum]

I've never seen in literature on system design, or nor can imagine sense for two filters.
One good pleated filter is a good choice and most systems can handle average pleated 1" filter.

 

[John Gayewski]

This is pretty simple. You either want more filtration and less air flow with more strain on thr air handler. Or you want less filtration, more air flow, and a air handler that doesn't work as hard. It's a simple trade off. Its what is important to you individually.