HEPA Filters

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NC
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I've been running a couple of HEPA filters in my house for a several years, one on each floor. They seem to do an efficient job judging by the dirt that accumulates on the prefilters. Filters are expensive for these and they use plenty of electricity. Would I be just as well off buying high end furnace filters and running the fans? Anybody else use HEPAs? [Linked Image]
 
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24,604
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Upstate NY
I would get one of those large filter housings installed into the return of your furnace. They have a huge filter surface area.
 
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3,014
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Ca.
I wouldn't use my house furnace and ducting as an air cleaner, but a high merv filter that doesnt cause too big a pressure drop is always a good idea. I stopped buying air filters that use proprietary media and instead use high merv furnace filters on a box fans. Doenst look as pretty for sure but a Dylos particle counter didnt see the difference between this and my blueair 650 E I'm filtering a construction area here - but you get the idea...... [Linked Image]
 
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Missouri
I used the exact same box fan and furnace filter set up a few years back when doing some remodeling. It sure did collect a lot of sheet rock dust.
 
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New England
I have the same (or similar) filter as the OP. We ran it for years without having to replace the filter. I vacuumed the pre-filter media and media with a handheld vac (dyson) with a washable filter. This worked for several years. For S&G's, I just replaced the larger filter with a new aftermarket one and can't tell the difference in sound or air-flow. We only run a filter in our bedroom, because we have pretty bad seasonal allergies and wanted to have one "clean" space. We open the windows throughout the rest of the house during cool/warm days, but leave our bedroom shut-up. Seems to work. I start to cough when I come out of the room for the first hour or so, until my antihistamine kicks in or I get used to the allergens. // That box-fan-and-home-filter idea looks really cool. How much airflow are you really getting out of it, though? I would swear that I tried that before and it was putting out almost nothing for airflow, so I gave up on the project. In contrast, my bedroom filter puts out enough air that, while it's in the corner, we can feel the air that bounces off the high ceiling in our bed in the center of the room.
 
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Not all house dust is created equal. I live 1/2 mile from one of the busiest freeway interchanges on the West coast. This combo rubber, brake, tailpipe dust is extremely nasty - when concentrated in my pool skimmer it makes a rainbow so I know it's loaded with oil as well. I take all reasonable steps to reduce this indoor pollution. UD
 
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Ca.
Originally Posted by gathermewool
That box-fan-and-home-filter idea looks really cool. How much airflow are you really getting out of it, though? I would swear that I tried that before and it was putting out almost nothing for airflow, so I gave up on the project. In contrast, my bedroom filter puts out enough air that, while it's in the corner, we can feel the air that bounces off the high ceiling in our bed in the center of the room.
it's pretty good with w a Merv 12/13 or Home depot "FPR 10" it moves a decent amount of air for the first month In terms of clean air delivery rate with a new filter. A lasko box fan can move 2500 CFM on high - I'd guess this cuts down to half or so with a high Merv filter - which is still VERY high in terms of CADR but I haven't used a flow gauge on it. When teh airflow slows down enough to be noticeable -I toss it. In a cleaner environment, I've had them go 6 months... It works well enough for me that I won't buy dedicated air filters anymore because of filter availability, cost, and the difficulty to clean - my blueair 650 ( a highly rated brand) CANNOT be fully cleaned. Heres 7 days in light construction with a different filter. UD

IMG_9264.jpg
 
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WA
Originally Posted by UncleDave
I wouldn't use my house furnace and ducting as an air cleaner, but a high merv filter that doesnt cause too big a pressure drop is always a good idea. I stopped buying air filters that use proprietary media and instead use high merv furnace filters on a box fans. Doenst look as pretty for sure but a Dylos particle counter didnt see the difference between this and my blueair 650 E I'm filtering a construction area here - but you get the idea...... [Linked Image]
Ya know.. that's a good idea. 👍
 
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3,014
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Ca.
From a 3rd party Aerospeed box fan: No filter: 10.2 mph 1" MERV8 filter: 6.3 mph 4" MERV11 filter: 8.4 mph Lasko Premium Weathershield box fan: No filter: 11.9 mph 1" MERV8 filter: 9.2 mph 4" MERV11 filter: 10.6 mph
 
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WA
Originally Posted by UncleDave
From a 3rd party Aerospeed box fan: No filter: 10.2 mph 1" MERV8 filter: 6.3 mph 4" MERV11 filter: 8.4 mph Lasko Premium Weathershield box fan: No filter: 11.9 mph 1" MERV8 filter: 9.2 mph 4" MERV11 filter: 10.6 mph
I've got several box fans that I use in the summer and I hate pulling in the pollen laden air from the trees and what not. I'm gonna do this.. great idea. Tx...... (I do use multiple HEPA filters around the house but it always seemed counter productive to be pulling in unfiltered air during the spring and summer months)
 
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7,991
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New England
Uncle Dave, Thanks for the reply, sir. Any issues with burning out the motors on the box fans, long-term? I'm sure they're probably designed not to die, even if flow is dead-headed (fan falls over), but how long have you been doing this and have you had any deleterious effects (e.g., more motor noise?) // I've got a VERY expensive 5-stage HEPA filter, as well that is completely washable (not sure how that works, but it's been doing a great job). The problem is that the motor is making a ton of noise, especially at low speeds. New, it was whisper quiet. Now, I can hear all the way across a second large room from where it's running. The kicker: I was able to disassemble and actually remove the motor pretty easily, but replacements are not offered, according to the company!!! I still run the filter, because it does do a great job (based on how quickly it becomes dirty), but I've got to imagine that the motor is causing additional electrical draw (it ran too hot to hold in my hand, with the motor out of the housing - I'm sure it's much cooler with the fan providing cooling, of course!); extra noise and heat = more power being used. Oh, it does look pretty smirk2
 
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WA
Originally Posted by gathermewool
Uncle Dave, Thanks for the reply, sir. Any issues with burning out the motors on the box fans, long-term? I'm sure they're probably designed not to die, even if flow is dead-headed (fan falls over), but how long have you been doing this and have you had any deleterious effects (e.g., more motor noise?) // I've got a VERY expensive 5-stage HEPA filter, as well that is completely washable (not sure how that works, but it's been doing a great job). The problem is that the motor is making a ton of noise, especially at low speeds. New, it was whisper quiet. Now, I can hear all the way across a second large room from where it's running. The kicker: I was able to disassemble and actually remove the motor pretty easily, but replacements are not offered, according to the company!!! I still run the filter, because it does do a great job (based on how quickly it becomes dirty), but I've got to imagine that the motor is causing additional electrical draw (it ran too hot to hold in my hand, with the motor out of the housing - I'm sure it's much cooler with the fan providing cooling, of course!); extra noise and heat = more power being used. Oh, it does look pretty smirk2
All my Holmes filters have gotten noisy..I hate them actually. I cut my own filter media, using furnace filter media, to save money but the noise as you mentioned can make watching TV impossible at times.
 
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3,014
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Ca.
Originally Posted by gathermewool
Uncle Dave, Thanks for the reply, sir. Any issues with burning out the motors on the box fans, long-term? I'm sure they're probably designed not to die, even if flow is dead-headed (fan falls over), but how long have you been doing this and have you had any deleterious effects (e.g., more motor noise?) // I've got a VERY expensive 5-stage HEPA filter, as well that is completely washable (not sure how that works, but it's been doing a great job). The problem is that the motor is making a ton of noise, especially at low speeds. New, it was whisper quiet. Now, I can hear all the way across a second large room from where it's running. The kicker: I was able to disassemble and actually remove the motor pretty easily, but replacements are not offered, according to the company!!! I still run the filter, because it does do a great job (based on how quickly it becomes dirty), but I've got to imagine that the motor is causing additional electrical draw (it ran too hot to hold in my hand, with the motor out of the housing - I'm sure it's much cooler with the fan providing cooling, of course!); extra noise and heat = more power being used. Oh, it does look pretty smirk2
No problems with fan motors 2 years in run mostly at low speed 24/7. Dad built a grip of these for his wood shop that takes up most of a 5 car garage, he built a box with multiple staged filters that just slide in -and he hasn't lost one at 3 years yet. ......at 20 bones a throw I'm not worried about it either. My blueair has three speeds - 1 ineffective,2 barely effective, and 3 roaring but effective. Whereas a box fan on 1 or 2 seems to move as much if not more air much more quietly. A Nordic pure with activated carbon did a pretty good job of killing the odor of hot mopping a shower floor. UD
 
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Ohio
Interesting topic. We use 20X25X5 Lennox CarbonClean MERV16 filters. The air pressure drop is lower than that of a 1" filter due to the mass amount of surface area. Our house has significantly less dust in it since we have switched to this filter. We also have a Miele U1 vacuum that does not emit any particles what so ever. Both of these are a huge help. I have considered taking a box fan and doing the exact same thing as above because of the low cost and simplicity, however, we just don't have the need for it.
 
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Ca.
Originally Posted by Dorian
Interesting topic. We use 20X25X5 Lennox CarbonClean MERV16 filters. The air pressure drop is lower than that of a 1" filter due to the mass amount of surface area. Our house has significantly less dust in it since we have switched to this filter. We also have a Miele U1 vacuum that does not emit any particles what so ever. Both of these are a huge help. I have considered taking a box fan and doing the exact same thing as above because of the low cost and simplicity, however, we just don't have the need for it.
If one wants to spend more money you can tape a thicker filter to a box fan. Are you using your house furnaces fan to recirculate air on a regular basis ? Thats certainly a nice, but extremely expensive filter, how long before you replace it - do you use a restriction gauge or just guess? I have a Miele canister vac as well- very tight unit. UD
 
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