My suggestion is to install one 4 inch media filter at each furnace and eliminate all the other filters. I have two furnaces and condensers in my house and that is how it was set up. My filters last 12-18 months and cost about $33 each for the 16x25x4 size for the Carrier/Bryant brand. I have not tried cheaper filters.

There may not be much in cost savings but the 4 inch filter will last longer and provide better air flow.

Thanks. So, when you say eliminate can you clarify what you mean and are you an HVAC specialists? It was proposed to me by at least one company or two to remove the (7) one inch filters but still have that ductwork connected to the system. So, essentially, there would still be a grill there and ductwork which would be sucking in dust, etc. but no filter. It wouldn't hit the filter until it hits the thicker 4 inch filter at the respective furnace. My thinking is that this may cause more "stuff" to get inside the duct system which may equal more cleanings? Perhaps, I am completely off base but it seems logical.

I am not HVAC specialist.

You can remove the filters at the supply grills. Some dust will be pulled into the duct work but in my opinion very little collects in the duct work itself. The purpose of the filter is too keep the indoor coil clean. The coil traps a lot of debris and cleaning a coil is difficult. All the dust will be collected by the one filter in each system.

The main benefit of a 4-5" depth filter is that there is more surface area within the filter and so air restriction is much less than that of a 1 inch depth filter.

Air restriction costs money and can in some cases cause HVAC equipment to run at less than rated capacity of the equipment. Meaning a 4 ton system runs like a 3.5 ton or worse. Air restriction can also cause equipment failure to one degree or another.

Removing filters at grills is in my 'professional' opinion not worth the trouble. The amount of dust going into that grill will accumulate quite fast. Where do you think all these pictures that duct cleaners show in advertisements actually come from?

If you have air quality concerns you should look to a pro in this area and treat the air above and beyond what a filter is capable of doing on it's own. Just realize these types of systems will increase your maintenance costs above what your filter costs are now.

So what is one to do? You could have your filter cake and eat it too... ok not to appetizing to eat a filter. Honeywell makes a 5" media filter that can fit in your normal 1" width grill filter. However it will only fit if your filter grill is not mounted to rounded duct attachment without the proper clearance of 4" that is going to stick inside the filter grill. So you will have to check and see if you have the clearance needed for this to work.

The benefit is that these filters will last longer and you can breathe easy knowing your returns will not become full of dust bunnies. Which reminds me Easter Bunny tryouts are right around the corner... so get prepared now.

Here's a link to the filters --- notice the one inch lip on them?

PS: I AM A HVAC SPECIALIST.

Thanks for the advice. I think I will just continue to use the Merv 8 one inch filters in the 7 returns. My yearly costs is not that much once I figured out I can buy them at the local HVAC supply company without being a contractor. :) There honestly isn't that much dust that accumulates as it is. I've heard of the larger media filters that fits into the normal 1 inch width grill fitter. However, wouldn't that be extremely expensive considering I have 7 filters ? :) Maybe I should leave things the way they are and just focus on updating my units themselves and changing out ductwork if appropriate. Agreed? :) Appreciate your advice.

Think about all the nuisance and wasted time changing out all those 1" filters... surely that's a consideration...

IMO

However, wouldn't that be extremely expensive considering I have 7 filters ? :)

A 5 inch media filter will last much longer than a 1 inch. There is more surface area to collect the dust in a 5 inch media filter. It 'may' allow you to go 6 months to a year without a filter change. (depends how much dust your house creates)

The added benefit of a grill mount 5" media is that you could just select a few of the dustier return grills to put these 5" media filters in. Then put the 1 inch filters in those returns that typically get less dust.

If your only goal is trying to cut cost, save up some money and invest in the filter company who makes the filters you use. If they pay dividends and you invest enough --- then you get the filters for FREE.

Because it sounds like 7 filters every 3 months... you should own a filter company by now. LOL.

I have one 24x30 central hall return. I was using a 1" filter for 3 years without an issue, changing them monthly. A 3 pack at HD cost $9. Last summer I tried a 5" return grille filter with 1" lip, at $45. After about 6 weeks, I started getting condensation in the bottom of my air handler (in the attic; split unit). I changed back to the 1" filter and haven't had a problem since.

I'm not condemning the deep filters, but they didn't help in my situation. Just sayin...

Stickman I doubt this had anything to do with the filter.

Your air handler in the attic.

Your AC condenses water from the air regardless what filter you have.

Humidity levels fluctuate wildly in an Attic.

It's not uncommon for a air handler to sweat and drip into the pan underneath it under various scenarios when the stars align. This all correlates to how much humidity not to mention 'DEW POINT' of the air in the ATTIC.

Dew point means, the temperature at which air turns to rain. ( more or less )

Magic 8 ball: You're welcome.

Austin...gee...thanks...

Much depend's on how well filters fit (preventing unfiltered air getting past filter around perimeter between filter and grill). Look for dirt and lint on old coils and inside return ducts to get a true picture of how well your present filters have been doing. As a benefit to air distribution, I would keep all 7 return grills and ducts even if using one filter at unit. Dirt and lint that collect's inside return duct before filter does no harm.

Dirt and lint that collect's inside return duct before filter does no harm.

until you remove the filter at the furnace and go back to grill mount filters all it takes is a little agitation with the blower on at that point and if you don't have allergies.

Magic 8 ball: After getting this information a swarm of cooties and dust mites have headed for klem's house... I knew it was them because they were screaming: 'FOOD!'

LOL.

Don't watch this before going to bed....

Exactly the kind of drivel we have come to expect from companies selling needless duct cleaning services.

Dust mites, parasites that feed off our waste have rarely bothered us years ago. The problem is that the envelopes which seal our homes have become tighter and tighter.

If you paid attention in the clip, it's not the dust mite that causes allergies. It's the buildup of their excrement. In an older home this probably wouldn't do much of anything depending on how severe someone is allergic to it. (I really don't have allergies so I can tell you Klem I am more in your camp than you realize.)

However, I have come across people throughout my illustrious career with so severe allergies that they just sneeze their head off unless they are heavily medicated. You have no idea.

You can do what you want... just realize there are people that have extreme allergies you do not want to become one of those people.

The pre-filter acts as a stop for large type dust. But you will have to go around every month or so and check them. I think the pre-filter idea is a bad idea for someone who is used to changing every 3 months.

If you try that 3 month span with a cheap see thru filter it may become so clogged that it gets sucked into your unit.

This doesn't mean you can't do the pre-filter. But it will likely involve more work, not less. The only reason to do this is to cut cost and reduce how often you have to replace the bigger more costlier filter. But you exchange cost for time and having to change the cheaper see thru filters more frequently.

Patrick,I did option 1 in several commercial environments,a few residential homes and have pre-filters on my units. I use spun polyester and paper pleat merv 8 pre filters along with merv 11 finals. Those with health issues should consider using merv 13 or higher as the final. Big box store 99 cent fiberglass filters are slightly better than running without a filter. I did some testing several years ago using professional tools monitoring and evaluating air flow,refrigerant pressures,temperature drop/increase across coils and compressor amps/reaction/performance. In the field,pre filters proved to enhance performance,equipment life and operating.maintenance costs. I have written about and reccomended the arrangement a number of times on this forum. Almost without fail,the idea has been met with disagreement claiming it to detrimentally restrict air flow. When dissenters are asked about flow restriction as result of poor quality filtration,they claim annual coil cleaning solve's that. Anyone know how to spell self-serving bias? The increase in final filter life is easily better than five times that where no pre filter is used. It is beneficial to performance and cost savings to install as large a filter rack as room allow's. As for option 2,that is actually how many large homes are set up and to respond to the big scary dust mite story, common sense tell's us different. If and when anything set's up shop inside the return,it will be trapped by a high quility filter and wind up at the landfill next filter change. With that in mind it should be evident that if one chose option 2 then later went to option 1,duct cleaning will not be required. Beating the drum regarding one's own credentials is pretty common on this forum. I am retired and have no reason to participate in self promotion but for what it's worth,I didn't attend the 2 week trade school training but I do have more than a few college credits in mechanical and electrical fields. Let the nay saying begin.

thanks klem1. Impressive response. I'm on the fence still but I like your response. I'm still debating the third option of just leaving the Merv 8 pleated one inch filters in the respective return grills and just replacing every 2-3 months or so. I have no unit filters currently. We bought our house in January and I just changed those filters a few weeks ago. Very little dust was on them. Maybe there is some value in the "if it ain't broke, don't fix it" approach.

"if it ain't broke, don't fix it" "

Don't you know service & repair companies hate that philosophy? I can't say as I disagree with staying with the system that has proven it's self. Adding a filter rack at time of installation isn't expensive. Some air handlers have a filter holder built in from the factory but imo 90% are too small and/or require odd filters. I reccomend installing an over sized filter rack between handler and return plenum if space allow's. Make sure filters are not some odd size that require custom order. If you want to cover all the bases,install a 2-3-4 or 5 inch rack while changing out units (there's little difference in material cost and none in labor).. At same time installer orders other sheet metal,he can order an adapter to slide 1 inch filters into the thicker rack. If you are a woodworker,an adapter is simple to fabricate. If one day you decide to start using thick filters you will be all set.

Not all service & repair companies. :) I also don't have an air handler as I understand it. I have gas heat. A furnace is usually the terminology used for a gas heating units that are inside of your home, that when attached to air conditioning, will also include an indoor evaporator coil box either on top or under furnace. I understand sometimes the furnace can also be electric, at which point it is an electric furnace or in professional terms an "Air Handler". So, to summarize, I either have an air handler/electric furnace or a gas furnace. In my case, I have a gas furnace.

Not all snakes bite but a fair share do so it's good to keep an eye on them just in case. :) Any place I said "air handler",for your application, it mean's same as furnace and function is exactly the same.