fiberglass filters are next to worthless for dust.

So I take it that you believe the fiberglass filters don't really protect the internal workings of a furnace/AC from anything smaller than a bug?

If you have a standard size, MERV7 and MERV8 efficiency filters will work just fine. If you have a custom size, Pleated MERV8's are also available in a new 'reusable' format.

I use a Honeywell 4" MERV10 pleated filter FC40R1078 which has a lip and fits into many return ducts designed for standard 1" filters. I'm getting a full year's use out of them in So. Louisiana, for about $4/mo. Much less restrictive than the 3M filters, and they're sturdy enough that they don't make crinkling noises when the blower kicks on.

I found the perfect remedy years ago. I cover the fibreglass filter with the black filter material they use on window AC units. The fibreglass one provides the support needed and the black filter does a superb job of filtering. Haven't had to clean a coil yet, after 15 years. The black filter will set you back about $1. Now go do it.

creek_side..........whats the brand you are referring too?.............thx

Flanders NaturalAire.

I am asking about using a 3M pleated dust reduction filter. After buying and installing this filter ..nine days later our furnaces started acting up. We replaced three sequincers. Finally the they checked our filter ...only to be told that the pleated filter should not be used on our furnace. That we should use the fiberglass filter. The pleated filter was restricting to much air flow.. We changed and everything is working properly now

The fact the filter is pleated does not cause excessive restriction. The pleating increases the surface area which is an attempt to make it less restrictive.

The 3M filtrete filters are known to be restrictive. The Naturalaire filters are pleated and not as restrictive. The fiberglass filters don't do a very good job. I would not add additional filtering the the fiberglass filter without knowing how much added restriction is being added.

I use the Flanders filters, too. Buy them in a 3 pack at Home Depot.

They say they last for 3 months, but I leave my air handler fan running 24x7x365 (cleans the air, helps balance temperatures) so I replace them monthly.

For some years I used the fiberglass filters. They would stop some dust, but I think it was just luck.

I've noticed my house is significantly less dusty now that I'm using the Flanders filters.

I have, however, had a problem with the Flanders filters.
My system uses 20x20 filters, and that isn't a nominal measurement, that is an absolute.

If the filters are even a tiny bit oversized, they jam and I can't get them into the filter box.

Whenever I buy filters I have to measure them very carefully.

FIBERGLASS FILTERS ARE ALMOST WORTHLESS.HVAC PEOPLE RECOMMEND THEM BECAUSE OF LOW AIR RESISTANCE.PLEATED FILTERS ARE MUCH BETTER BUT STAY AWAY FROM ANYTHING WITH A MERV RATING HIGHER THAN 8. THEY ARE TOO AIR RESTRICTIVE AND CAN CAUSE PROBLEMS WITH A/C COILS ICING UP OR HEAT EXCHANGERS BURNING UP. MAKE SURE THE PLEATED FILTERS YOU BUY HAVE AT LEAST 15 PLEATS PER FOOT. CHANGE PLEATED FILTERS EVERY 3 MONTHS OR SOONER IF YOU SMOKE OR HAVE PETS OR HAVE AN UNUSUALLY DIRTY ENVIRONMENT. I HIGHLY RECOMMEND AAF "PERFECT PLEAT" MERV 7 OR MERV 8 PLEATED FILTERS.

I use a washable electrostatic filter - seems to allow decent airflow, has saved me a fortune on the expensive disposables. Worked well with my dog in the house.

I have a deep filter tray with tabs for 1" filters or with the tabs folded up a 4" slides down in. 20x25x4" 6-8 merv pleated is what I run. If a person can run a 4" filter its unbelievable about the amount of actual filter media and surface area for air to flow in comparison to a 1" filter.

Like everyone else said... very high merv ratings cause very high restriction and a little dirt/dust really plugs them fast in comparison. I have seen 1400merv filters which is crazy. I have sealed my duct system and used brush on mastic but I know it is still not sealed perfect enough to justify a 1400 filter.

If the filter(s) are not right at the furnace/air handler and are behind the return vent putting a high merv on these systems pull even more air through unsealed nooks and crannies and in some systems it is gaping holes.

Some of the filterete filters don't really have that much air resistance. The problem appears when you get their micro allergen reduction series and above. Filterete's dust reduction and also their dust and pollen reduction have pretty low air resistance , so you should be fine with filterete. Fiberglass filters are worthless. They can't even filter salt. It's sad. (Don't try it when the filter is inside the system)

plain and simple fiberglass filters are just above worthless. The black filter media cloth over a fiberglass makes a secondary filter that has decent filtration but poor surface area and as dust starts to build up the air flow will drop like a rock.

My 4" thick filters have 12 FEET of filter media on a 20x25x4"

Click the link.. Surface area is key to any filter system if you really want it to perform.

Here is a link that might be useful: Here is a 4

I have replaced many a blower, sold many a furnace because of the 3M filters. 3M is trying to keep HVAC service techs in business. Seriously, pleated filters, change every 30-60 days.I highly recommend an electrostatic air cleaner. There is no filter, and you clean it every 6 months in the tub or with a hose.Gets out 98% of what harms you.

Low restriction for oil based furnace. Oil companies with good techs warn to use fiberglass filters on HVAC systems and use separate HEPA machine(s) for air quality throughout house. Most of us already own these if anyone in household has allergies. Remember, those burner and AC parts are slow boat 'imported' now. 🙄 Frozen coils in central air will ice over in summer when you need it most. Non starter, since once things overheat it can take up to 48 hours to get everything cool again in a heat wave.