Heating, Air Conditioning, Fridge, HVAC/furnace filter faced which way?


Hi Fred, I've got an easy one for ya, complete with a photo. I can't figure out of I have my furnace filter facing the right way. Seems as though there's an awful lot of dust lately piling up on everything. I'm wondering if I have it right. If you cant see on the photo, the arrows on the filter are pointing from the cold air return towards the furnace. I don't understand why it even matters but if I do have to turn it around, should I use a brand new filter? Thanks!


You got it right.

It looks like new construction. If so, you probably have construction debris in the supply ductwork that's becoming airborne when the blower operates. It always amazes me to find that kind of stuff downstream of an exotic filter.

Hopefully, the required turning vanes are provided at the filter inlet; if not, there's a huge pressure drop which would add to your power bill if the furnace has an ECM. Furthermore, a 16x25 is only good for 2-1/2 or 3 tons max, and the capacity the return duct may be less than that.


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Fred Weldin


I can't help you if your whatsis won't work, people (Especially if it's a refrigerator); I have no experience with appliances, and I haven't been involved with H&AC service and repair since March 08, 1996 (Thank the Lord); I always send a "standard" reply to appliance questions and H&AC "Service and Repair" questions (about 20 a month), so if you want to know why your whatsis isn't working like it used to, ask someone else. A lot of my answers arenít read by the questioners; in that event, I always send reminders to read the answers for a month or more (the word "idiots" comes to mind - actually there's another more appropriate word, but discretion prevents its use here). If you have questions about how big a unit you need, if one room's warmer than the others, if you want an opinion oas to scope of work on bids received, etc. just ask. Do visit www.askweldin.com, there's a lot of good information on sizing, ductwork, efficiency, as well as some techniques accomplished DIY-ers can use to troubleshoot and improve their H&AC. Finally, I want to thank all of the kind, serious people whom I meet here: I enjoy working with you. My wife says I'm "snarky" from time to time; as for you others, please use your imagination as to the responses swirling on the snarky side of my brain when I read your questions.


53 years in the business. See www.askweldin.com


B of ME U of D 1965, numerous classes, seminars and a lot of "Hands On" learning since.

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