Washable Furnace Filters

[KennyG]

I'd say that their cleaning directions are spot on - ours catches a lot of dirt and I was cautioned by a friend who is in HVAC that the one we have at least, passes less air than a typical, normal furnace filter, so you really don't want to let them get clogged up.

I suppose lack of airflow could cause the heat exchanger to overheat.

It's really more of a problem with A/C. Low air flow will cause the coil to freeze. I run high efficiency filters (the corregated filter material) in the winter but cheap fiberglass ones in the summer to avoid freeze up. Of course, it may be my systems isn't quite up to specs.

 

[5030]

At least for a vehicle. Not sure about their furnace filters.

Right on. Oiled Gauze don't trap anything smaller then pea gravel...

 

[rekees4300]

Has anyone had experience with the washable furnace filters and what was your experiences?

Yes I've been using a washable furnace filter for years. Clean it monthly using "Allergy Free Electrostatic Filter Cleaner'".

Allergy-Free Electrostatic Filter Cleaner Spray | National Allergy

 

[orezok]

What is the MERV rating on the washable filters? Anything less than a 10 is a rock catcher.

 

[rekees4300]

The correct MERV rating depends on several variables.

All about MERV ratings | FilterBuy

 

[jaxs]

I've overseen hands on and supervised hundreds of air conditioning systems. Never saw a washable filter that did a good job. For average conditions,I reccomend Merv 8 pleated filters. Where there's health issuse highr merv should be considered. Filter must fit to prevent air deturing around it. Big box stores can order sizes they don't keep in stock. High effeciency filters restricting air flow is a mis-guided myth and here's why.
Running a cheap fiberglass filter a few months will alow enough stuff through to collect on coils and restrict flow way more than any filter will. I've cleaned enough coils to know that. There's another option for odd size filters. Spun polyester that sells by the roll is about equivelent to merv 6 which is much better that fiberglass. Among other ways,a fair filter can be fashioned with 2x2 welded wire and cut to fit polyester. How can you tell if your filter is doing the job? There should not be any dust or lint on duct walls downstream of filter. If there's dust and lint on duct walls,you can bet there's plenty trapped on coils.

 

[cqaigy2]

I've overseen hands on and supervised hundreds of air conditioning systems. Never saw a washable filter that did a good job. For average conditions,I reccomend Merv 8 pleated filters. Where there's health issuse highr merv should be considered. Filter must fit to prevent air deturing around it. Big box stores can order sizes they don't keep in stock. High effeciency filters restricting air flow is a mis-guided myth and here's why.
Running a cheap fiberglass filter a few months will alow enough stuff through to collect on coils and restrict flow way more than any filter will. I've cleaned enough coils to know that. There's another option for odd size filters. Spun polyester that sells by the roll is about equivelent to merv 6 which is much better that fiberglass. Among other ways,a fair filter can be fashioned with 2x2 welded wire and cut to fit polyester. How can you tell if your filter is doing the job? There should not be any dust or lint on duct walls downstream of filter. If there's dust and lint on duct walls,you can bet there's plenty trapped on coils.

Seems like a reasonable observation. Interesting information of diying a filter.

 

[not2old]

My house has a Climate Master geothermal furnace with a washable filter. It's about 13 years old and I wash it once a year by blasting it with the hand held shower on full hot. It appears to be some sort of aluminum mesh about 2.5" thick with an aluminum frame. I don't know how well it filters but seems comparable to those cheap replaceable ones you mostly see. We have considered getting an electronic unit.

 

[kenmac]

It's really more of a problem with A/C. Low air flow will cause the coil to freeze. I run high efficiency filters (the corregated filter material) in the winter but cheap fiberglass ones in the summer to avoid freeze up. Of course, it may be my systems isn't quite up to specs.

Actually, It would cause issues on both ends.. As an example....If you have a 80,000 BTU gas furnace @3 tons of air flow.. The furnace is designed to return enough air across the HE, so as to not not let the HE get too hot.. Of course there are (or should be) limit switches that should cycle the furnace burners off, should it not be able to flow enough air across the HE.

I have seen filters so restrictive, that the furnace would only fun a few seconds, and shut down on one of the limits to keep the furnace from melting to the ground.

Of course, once that limit cools down, the cycle starts all over again.
Burners come on, fan comes on and tries to blow air across the HE. Due to filter restrictions, the limit switch pops, burners shut down again

If you're going to use a more restrictive return filter, You should check your air flow, and adjust accordingly .
Even if it means increasing the return duct size