My parents had washable filters. It was my job to wash them. I would never buy a washable filter. It is far easier to replace the 4 inch thick paper filter every 6 or 12 months. These filters have a very high surface area, are long lasting, and MERV 11 means they are very efficient at catching dust.

I've been told by an ac installer that the dense air filters can sometimes reduce the efficiency of the ac. They can reduce the air output of the blower.

While potentially true, I have had no issues using the MERV 11 filters. These filters reduce both dust and noise in the house. No problem with air flow. I recommend them over the MERV 8 filters.

I buy a MERV 12 filter once a year at Lowes for $35. How long would it take me to start saving money by washing a filter monthly?

You will save money with washable filters, but you can probably also save money by buying the filters from Amazon instead of Lowes.

If you never replaced the filter then it would never save you money.

If you replaced the filter as recommended, every three months or so, then it would save money in the first year.

I don't recall what mine cost but I think it was in the neighborhood of $90. Given that, if you insist on replacing your $35 filter once per year then you would save money in the third year.


EDIT: I wash mine quarterly, not monthly.

This is correct with filters MERV 11 and above. Not the MERV 8 washable filters.

No issues with mine. Be sure to let the filter dry completely before putting it back in after washing. If in doubt about how dry, just run the furnace fan for an hour after you install.

IMO if reusable don’t let dust pass inside unit they probably work Ok? Look in squirrel cage see how dirty it is? that’s where fine dust going to build up. In older units merv 11s might reduce air flow and efficiency. I used merv 11s in my older unit and I could tell difference is flow and sound. I had to turn up fan. My older unit gone now and I just stick with carrier suit case filter yearly replacement. Costly but designed for my unit.

Merv 11 paper the best
 

Our filter is supposed to be changed annually. At best your washable filter is Merv 8 runs anywhere between 130-150 dollars and will lose efficiency over time. A Merv 11 paper filter 20x20x 4 is only $30 and is much more efficient.

To even consider a washable filter, ask yourself how long you plan on living in your home. Then calculate lost efficiency and the probability that it will end up in the trash sooner or later. Most have their ducts eventually cleaned anyway within 5 years?

The washable filter sold in the villages DOES NOT loose efficiency over time. However, a paper filter that is allowed to accumulate dust (etc.) WILL loose efficiency over time.

Here is an interesting Bob Villa article on air filters.

How Often to Change a Furnace Filter, Solved! - Bob Vila

Please explain.
Comparing two filters that are both MERV 8, similar in construction, and start off the same new condition.
As they both trap dirt, both become plugged. They have less room for air to flow, thus restricting air flow.
If the paper one is becoming more restrictive, that would imply that it is capturing more dust. What else would cause it be more restrictive?

It doesn't really work that way for many systems. Systems with an ECM motor in the air handler will continue to produce essentially the same CFM as the filter becomes loaded. ECM motors are programmed to provide a specific amount of air flow. Of course, this is up to a point. A filter can become so loaded that the ECM motor cannot compensate. If you have a 4" media filter and no outstanding sources of "stuff" in the air, annual filter changes should be fine.

I have been using MERV 11 paper filters for several years with no issues. They work better than MERV 8. I change them at least every 6 months. If I had pets, I would change them more often. I don't agree with leaving a filter in the unit for a year, even though some filter manufacturers say it can be done. Also, I am always skeptical when a technician provides advice that doesn't seem to be based on any personal experience or research. Any filter will restrict air flow, especially when it gets dirty. That is just how it works. If the filter is very dirty when you replace it, you are not replacing it often enough.

Flow controlled closed loop motor controls have nothing to do with the amount of stuff captured by either filter type. It only alters the blower speed to compensate for a plugged filter. That does not make the filter material any different.

Sounds like that reply is implying that the paper filter will capture more stuff (even with the same MERV rating), and the blower motor speed will need to be increased.

Still looking for a real answer to my question. Why will the paper filter become more restrictive to the washable one, given that both are MERV 8 and both are the same physical construction.