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-   -   what is best furnace filter to buy? (http://www.diychatroom.com/f17/what-best-furnace-filter-buy-95257/)

dinosaur1 02-12-2011 10:25 AM

what is best furnace filter to buy?
 
I currently have a metal furnace filter and have used it for the last 5 yrs. Should I stick with it or switch to a Filtrete High Performance Filter?

My local Sam's has these.
http://www.samsclub.com/sams/shop/pr...rnace%20filter

yuri 02-12-2011 11:15 AM

Filters except 3m are rated in MERV (google that for more info). The higher the merv the more air is restricted and the harder it is for your furnace fan to move it. This can result in an overheated and damaged furnace or frozen and damaged AC. Only way to know for sure is to try it and check the temp rise thru the furnace after is has run for 5 minutes. Stick a thermometer in the supply duct downstream a foot away from the plenum and subtract the house temp from it and check the temp rise specs on the model # sticker inside the furnace. ie:35-65degF. I recommend a Merv 8 filter and unless you have a newer furnace with an ECM motor and large ductwork you can have problems with the more restrictive types. AC needs checking by a Pro to see if it has enough airflow.

http://www.furnacefiltercare.com/merv-ratings.php

dinosaur1 02-12-2011 11:29 AM

Quote:

Originally Posted by yuri
Filters except 3m are rated in MERV (google that for more info). The higher the merv the more air is restricted and the harder it is for your furnace fan to move it. This can result in an overheated and damaged furnace or frozen and damaged AC. Only way to know for sure is to try it and check the temp rise thru the furnace after is has run for 5 minutes. Stick a thermometer in the supply duct downstream a foot away from the plenum and subtract the house temp from it and check the temp rise specs on the model # sticker inside the furnace. ie:35-65degF. I recommend a Merv 8 filter and unless you have a newer furnace with an ECM motor and large ductwork you can have problems with the more restrictive types. AC needs checking by a Pro to see if it has enough airflow.

http://www.furnacefiltercare.com/merv-ratings.php

But would you stick to a metal or paper filter overall?

yuri 02-12-2011 11:51 AM

Post a pic of the metal filter. IMO none of them and the so called "electrostatic" membrane ones are worth a darn. MOST people don't clean them properly and they tend to gum up and plug up internally with scum. I have seen lots of frozen and damaged ACs from those filters not been cleaned properly and I don't recommend them at all. The pleated MERV filters are guaranteed/rated to do what they are supposed to vs. the "buy guess and by golly" aspect of those other filters. For under $20 for a 3 pack of Merv 7-8s how can you go wrong. ACs and furnaces are over $4000 so the price of the filter is hardly an issue IMO.

dinosaur1 02-12-2011 12:25 PM

Quote:

Originally Posted by yuri
Post a pic of the metal filter. IMO none of them and the so called "electrostatic" membrane ones are worth a darn. MOST people don't clean them properly and they tend to gum up and plug up internally with scum. I have seen lots of frozen and damaged ACs from those filters not been cleaned properly and I don't recommend them at all. The pleated MERV filters are guaranteed/rated to do what they are supposed to vs. the "buy guess and by golly" aspect of those other filters. For under $20 for a 3 pack of Merv 7-8s how can you go wrong. ACs and furnaces are over $4000 so the price of the filter is hardly an issue IMO.

My furnace was installed when the home was built. 1997.

dinosaur1 02-12-2011 12:38 PM

Quote:

Originally Posted by yuri
Post a pic of the metal filter. IMO none of them and the so called "electrostatic" membrane ones are worth a darn. MOST people don't clean them properly and they tend to gum up and plug up internally with scum. I have seen lots of frozen and damaged ACs from those filters not been cleaned properly and I don't recommend them at all. The pleated MERV filters are guaranteed/rated to do what they are supposed to vs. the "buy guess and by golly" aspect of those other filters. For under $20 for a 3 pack of Merv 7-8s how can you go wrong. ACs and furnaces are over $4000 so the price of the filter is hardly an issue IMO.

I found these at Sam's Club. What do you think?

Filtrete

Allergen reduction filter
1200 performance rating
Lasts up to 3 months
Approved by the American Lung Association
2 twin packs

Jackofall1 02-12-2011 12:56 PM

Quote:

Originally Posted by dinosaur1 (Post 589633)
I found these at Sam's Club. What do you think?

Filtrete

Allergen reduction filter
1200 performance rating Equal to a MERV 12
Lasts up to 3 months
Approved by the American Lung Association
2 twin packs

You may experience problems with that one

Mark

dinosaur1 02-12-2011 12:57 PM

Quote:

Originally Posted by Jackofall1

You may experience problems with that one

Mark

Why is that

Jackofall1 02-12-2011 01:14 PM

Yuri mentioned it already, you could try it, but be weary that you cause flame rollout, higher temp rise through heat exchanger than max design and AC "A" coil freezing in the summer.

Basically the better the filter the higher the resistance the higher the resistance the less air flow.

Go ahead try em, if they work for ya then cool, I would check the temp rise as a min, just to make sure you aren't cause heat exchanger problems.

Mark

dinosaur1 02-12-2011 01:16 PM

Quote:

Originally Posted by Jackofall1
Yuri mentioned it already, you could try it, but be weary that you cause flame rollout, higher temp rise through heat exchanger than max design and AC "A" coil freezing in the summer.

Basically the better the filter the higher the resistance the higher the resistance the less air flow.

Go ahead try em, if they work for ya then cool, I would check the temp rise as a min, just to make sure you aren't cause heat exchanger problems.

Mark

Where did you find a 3 pack for under $20?

Jackofall1 02-12-2011 01:20 PM

Quote:

Originally Posted by dinosaur1 (Post 589664)
Where did you find a 3 pack for under $20?

I didn't I believe what Yuri was getting at was, the filters you can use without fear of causing problems with your systems sell for about $20 for a 3-pack.

It would be like the Filtrete with a rating of 1000, I believe.

Mark

dinosaur1 02-12-2011 01:32 PM

Quote:

Originally Posted by Jackofall1

I didn't I believe what Yuri was getting at was, the filters you can use without fear of causing problems with your systems sell for about $20 for a 3-pack.

It would be like the Filtrete with a rating of 1000, I believe.

Mark

The ones I found have a 1200 rating.

Michael Thomas 02-12-2011 01:41 PM

If you use a HVAC contractor who is into "measured performance" and actually checks pressures, they will generally find that ANY of the high MERV filters are creating excessive pressure on the return side and a reduced air flow across the heat exchanger / A-Coil to the point where system efficiency is significantly reduced.

One clue that this is occurring is "oil canning" of the ducting - when the blower comes on sides of plenum are bent inwards, and then pop back out, - often with an easily audible sound - when the blower goes off.

When I see that (unless it's because the return side of the systems his horribly mis sized) I know I will find either a badly obstructed (dirty) filter, or one of the high MERV types.

dinosaur1 02-12-2011 01:43 PM

Quote:

Originally Posted by Michael Thomas
If you use a HVAC contractor who is into "measured performance" and actually checks pressures, they will generally find that ANY of the high MERV filters are creating excessive pressure on the return side and a reduced air flow across the heat exchanger / A-Coil to the point where system efficiency is significantly reduced.

One clue that this is occurring is "oil canning" of the ducting - when the blower comes on sides of plenum are bent inwards, and then pop back out, - often with an easily audible sound - when the blower goes off.

When I see that (unless it's because the return side of the systems his horribly mis sized) I know I will find either a badly obstructed (dirty) filter, or one of the high MERV types.

So I should stick to a 1000 rating instead of 1,200?

Jackofall1 02-12-2011 01:46 PM

In a nut shell, yes

Mark


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