Furnace Filter/Air Cleaner Question

[dbhost]

I wanted to post a word of caution about http://www.discountfilters.com/. The response we are getting from the community here about this site has been somewhat surprising. To restate what Mark said, the post asking about the site did not meet the criteria for spam. However, I did want to caution anyone that is considering doing business with that company. A cursory check at the BBB shows that there are no records for them. I don't know about other countries, but the BBB in the US does a pretty good job on keeping tabs on legitimate businesses, and any lack of BBB records steers me very far away from doing business with a vendor.

[master53yoda]

Furnace filters in residential furnaces play 2 rolls probably the most important roll is collecting as much airborne material as possible "Without causing undo pressure drop" I have used the 4" filters for close to 25 years as I have always been able to get them from the HVAC wholesale houses. They have been used in commercial applications since the 50s.

Residential furnaces blower capabilities are limited to about .75" water column static pressure total, this must include the losses of the ducting, AC coil, and filter. (Your dust collector will develop about 2.5" static and works at 1.25") Commercial system can develop as much as 4" of static pressure.

This doesn't leave much for the filter only about .2" max. then it must be changed, (commercial filters aren't changed until they are losing between .75 and 1") in residential applications a 20x20x1" filter is only good for about 1200 CFM or 36000,BTU cooling. a 20x20x4" filter is good for about 2500cfm. or 60000 to 72000 cooling. 12000 = 1ton cooling. The static drop on most High efficiency 1" filters is more then the system can handle and causes operational problems with the furnace and AC equipment

A 4" filter is about 85% +or- 5%as compared to a electronic that is 93% + or -2%. The electronic filter losses efficiency as the plates become contaminated, a media filter gets more efficient as the spaces fill up in the filter.

so the bottom line is the Electronic filters are the most efficient IF they are cleaned often enough. 30 to 90 days.

A 4"filter can normally go about a 12 to 18 months before they exceed the .25 change limit.
EXCEPTION: If you live in an environment with high humidity such as Florida etc. They probably will start to grow mold after about 90 days. One of the solutions to this is ultra violet lighting in the return air duct.

I use a static pressure reading to tell me when to change my filter.

I hope this helps a little

art

[os1kne]

I wanted to post a word of caution about http://www.discountfilters.com/. The response we are getting from the community here about this site has been somewhat surprising. To restate what Mark said, the post asking about the site did not meet the criteria for spam. However, I did want to caution anyone that is considering doing business with that company. A cursory check at the BBB shows that there are no records for them. I don't know about other countries, but the BBB in the US does a pretty good job on keeping tabs on legitimate businesses, and any lack of BBB records steers me very far away from doing business with a vendor.

I don't know anything about Discount Filters, but I'd caution against using the BBB as the sole means to determine whether a business is legitimate or not. I don't really have anything against the BBB, but you have to remember that the BBB is a membership organization. You pay them money to be a member and agree to some "rules" about customer dispute resolution, etc. This gets you listed in their information and over time a certain grade of accreditation. Not being a member doesn't mean that you're a "bad business" and being a member doesn't mean that you're a "good business".

Case in point: The firm that I work for is the largest firm in its industry in the county that I live in - probably more than double the size of the #2 firm in the county. The firm has been in the county for nearly 30 years and has always had a very good reputation. If you look for companies in our area in our industry on the BBB website, you won't see any listing for us. So, what does this mean? - only that we have chosen not to become members of their organization.