furnace filters

[mjoekingz28]

Can the $1 blue fiberglass filters be beat?

I was thinking of getting Purolator furnace filter since I had good success with the automotive ones. I cannot find them locally, but on Amazon a dozen are $50. They say they last 3 months, so that is 3 years of filters, minus half for a double return air system and that works out to 18 months.

I saw 3M has a 'for life' filter for about $50. You just hose it off with water and if/when it does get punctured you pay $8 to mail it back for replacement.

 

[ueberooo]

They don't catch much dust. However, sometimes I use them as pre-filters in the return vents in order to make the actual furnace filters last longer. I usually get the generic paper filters (~ $4) at my local Do-it-best hw store rather than some high end 3M. The paper seems of fine enough mesh to be catching a good amount of dust.

 

[dwcopple]

All I know is you should avoid 3M filters like the plague. Horribly restrictive according to HVAC guys in the know.

 

[OVERKILL]

Originally Posted By: dwcopple
All I know is you should avoid 3M filters like the plague. Horribly restrictive according to HVAC guys in the know.


I've heard the same.

 

[Pablo]

Originally Posted By: dwcopple
All I know is you should avoid 3M filters like the plague. Horribly restrictive according to HVAC guys in the know.


I've seen people post the same thing but.......Is there real data behind this?

 

[JHZR2]

Originally Posted By: Pablo
Originally Posted By: dwcopple
All I know is you should avoid 3M filters like the plague. Horribly restrictive according to HVAC guys in the know.


I've seen people post the same thing but.......Is there real data behind this?


+1. Especially comparing particle counts and filtration efficiency to pressure drop?

The reality is that the 3M is probably a much better filter, and the filtration level is higher, so the resistance to flow is also higher, on and on.

To some it may be a worse filter. To others, it may be exactly what is needed to prevent pollen, dust and mold (though IMO filtered air is why we have such high rates of asthma and allergy these days).

 

[Cressida]

Originally Posted By: JHZR2


To some it may be a worse filter. To others, it may be exactly what is needed to prevent pollen, dust and mold (though IMO filtered air is why we have such high rates of asthma and allergy these days).



What makes you say filtered air is related to higher rates of asthma and allergy ? Never heard that one before.

 

[Hermann]

Originally Posted By: Cressida
Originally Posted By: JHZR2


To some it may be a worse filter. To others, it may be exactly what is needed to prevent pollen, dust and mold (though IMO filtered air is why we have such high rates of asthma and allergy these days).



What makes you say filtered air is related to higher rates of asthma and allergy ? Never heard that one before.



Just like using anti-bacterial soap all the time, it lowers your resistance to the allergans. JMHO

 

[JOD]

Originally Posted By: OVERK1LL
Originally Posted By: dwcopple
All I know is you should avoid 3M filters like the plague. Horribly restrictive according to HVAC guys in the know.


I've heard the same.


lots of car guys "in the know" recommend using 10W30 in everything. Just sayin'.

I'm with Pablo--I'd like to see some sort of documentation...except that I don't have a furnace filter...

 

[GMBoy]

I use the 3M filters only because my son has Asthma and I use the mid grade version. It seems a balance between good filtration and air flow. I used the higher one once and could tell right away just how restrictive it was. You gotta pay for the increased filtration and air flow is the price.

 

[Nick R]

We use the High end 3M filters, and we've never had any problems. Two of the famiy members have asthma and they do help.

 

[Quattro Pete]

I've been happy with the performance of Ace Hardware branded pleated filters. They are MERV 8 rated and when on sale, they can be had for as low as $2 a piece in my size (16x25x1).

 

[tom slick]

Originally Posted By: Quattro Pete
I've been happy with the performance of Ace Hardware branded pleated filters. They are MERV 8 rated and when on sale, they can be had for as low as $2 a piece in my size (16x25x1).


I'm happy with ACE pleated filters also.

 

[JHZR2]

Originally Posted By: Hermann
Originally Posted By: Cressida
Originally Posted By: JHZR2


To some it may be a worse filter. To others, it may be exactly what is needed to prevent pollen, dust and mold (though IMO filtered air is why we have such high rates of asthma and allergy these days).



What makes you say filtered air is related to higher rates of asthma and allergy ? Never heard that one before.



Just like using anti-bacterial soap all the time, it lowers your resistance to the allergans. JMHO


Exactly my thought. Havent done research on it, just looking at trends. My wife and I grew up with open windows - minimal allergies. Friends who grew up without central AC also have minimal allergies. Friends who grew up with conditioned air seem to have more cases of allergies.

Im not saying it IS THE ANSWER, Im just saying that I see a trend, FWIW, and it seems to me that the less exposure you get to these things in the air, round the clock, the worse you are. Plus, filtered air is not particle free, it just has all the finest particles, the ones that lodge deeper into lung tissue (some diesel-gas studies have looked at that).

Then, look into the ducts and innards of HVAC, and the ones Ive seen have a LOT of dust and sometimes mold inside. Don't invoke response from big, natural particles, but instead all the finest, nasty for you junk, and it is bound to create an inflammatory/immune response.

 

[OtisBlkR1]

in my old house i would go and buy the cheapest thing i could find.. and that house was incrediably dusty, many times i would check the filter and find it bent in half doing zero filtration. When i moved into my new place last summer (middle of the woods way out in the country) and my little boy was born, i reflected on those old filters and all they let pass and started looking more closely. I purchased 3M, I still dust due to OCD and penut butter on everything (2yr old) but my house is very dust free, since switching to 3M i cant see dust in the sunlight through the windows on a sunny day, they probably are more restrictive (there filtering more) I replace my $12 house filter every 6-7 weeks on apperance, the package says three months but i think it looks spent by 2 months..

 

[bruiser123]

I have been using Slick 50 to lube my furnace motor for about 25 years now. My furnace is almost 50 years old and I expect it to last another 25 years hopefully.

 

[OVERKILL]

Originally Posted By: JOD
Originally Posted By: OVERK1LL
Originally Posted By: dwcopple
All I know is you should avoid 3M filters like the plague. Horribly restrictive according to HVAC guys in the know.


I've heard the same.


lots of car guys "in the know" recommend using 10W30 in everything. Just sayin'.

I'm with Pablo--I'd like to see some sort of documentation...except that I don't have a furnace filter...


Our old furnace (from 1976) was being serviced by the gas company.

I had a 3M filter in it.

The guy came up and said that the motor was running WAY too hot (he checked it with an IR gun) because of the restrictive filter. He said that those old furnaces use the air flow through the air return to cool the motor and cutting down the flow caused the motors to run far too hot.

Changing out the filter to a cheap, less restrictive filter did in fact make a huge difference in how hot the motor ran. You couldn't put your hand on it with the 3M in there, with a regular filter, you could.

Would it make a difference on our new furnace with a direct-drive fan? Maybe, maybe not. We'd need some actual testing data I suppose.

 

[tom slick]

When a filter is too restrictive from being "full" or by the media used wouldn't it collapse? I've certainly seen collapsed regular media filters that were dirty but haven't seen a collapsing 3M Filtrete.

 

[KrisZ]

I'm not an HAVC guy, but I did some extensive reading when I was purchasing an AC system for my house.
What I found is that anything more than MERV 8, can cause premature furnace or AC problems. Furnace filters were never meant to clean the air inside the house, they were designed to protect furnace components.
Furnaces are designed to have a certain temp. raise across the heat exchanger, or temp. drop across the A-coil and this range is fairly narrow. If the filter is restrictive enough, it may cause the temp. raise or drop to be outside of the allowable range. This can cause all sorts of things like cracked heat exchangers, weak AC performance, furnace shutting down prematurely, or short cycling, to protect itself when the heat exchanger gets too hot.
There are furnaces with variable speed blowers that will compensate for additional air restriction, but that uses more electricity and the units are very expensive anyway, so not a lot of people have them.

In essence, if you or someone in your family needs clean air, get a proper air filtration system.

 

[Pablo]

I'm not at all doubting restrictive filters can cause problems in some systems. Is it really true that ALL 3M filters are overly restrictive? The two things are not the same issue.

I've run just about every filter known to man. Including several 3M varieties. Heater didn't seem to care.