Air Filters/Cleaners

dguy6789

Diamond Member
Dec 9, 2002
8,558
3
76
Any specific models to look at? I'm just looking for something that will help get rid of some dust and junk that seems to just linger in the air in a couple rooms of my house. I don't need the best or fanciest one, just something as cheap as possible that won't die in 6 months.

Thanks.
 

Howard

Lifer
Oct 14, 1999
47,982
10
81
Step 1) Purchase a box fan (its shape MUST resemble this - e.g. no curves)
Step 2) Purchase a good furnace filter approximately the same size as the fan
Step 3) Attach furnace filter to box fan (mind the orientation for both) - I use tape on mine
Step 4) ...
Step 5) Run box fan for profit
 

NoShangriLa

Golden Member
Sep 3, 2006
1,652
0
0

If you are going to do it, might as well do it right.

Install an Electrostatic HEPA filter for the whole house, and wire inline with the fan/blower.

 

0roo0roo

No Lifer
Sep 21, 2002
64,795
84
91
Originally posted by: Howard
Step 1) Purchase a box fan (its shape MUST resemble this - e.g. no curves)
Step 2) Purchase a good furnace filter approximately the same size as the fan
Step 3) Attach furnace filter to box fan (mind the orientation for both) - I use tape on mine
Step 4) ...
Step 5) Run box fan for profit

you'd need to build a containment box with louvers of a mesh screen so larger particles would have somewhere to sit else the furnace filter would only catch the really small stuff, the rest falling back into the flow.
 

Jeff7

Lifer
Jan 4, 2001
41,596
19
81
Originally posted by: Howard
Step 1) Purchase a box fan (its shape MUST resemble this - e.g. no curves)
Step 2) Purchase a good furnace filter approximately the same size as the fan
Step 3) Attach furnace filter to box fan (mind the orientation for both) - I use tape on mine
Step 4) ...
Step 5) Run box fan for profit
My worry is that that might be too much of a strain on the fan's motor. Those things are likely designed only to be able to fight the inertia of the fan blades and the resistance of free-flowing air. Making it try to suck air through a filter might overheat the motor.

 

Howard

Lifer
Oct 14, 1999
47,982
10
81
Originally posted by: 0roo0roo
Originally posted by: Howard
Step 1) Purchase a box fan (its shape MUST resemble this - e.g. no curves)
Step 2) Purchase a good furnace filter approximately the same size as the fan
Step 3) Attach furnace filter to box fan (mind the orientation for both) - I use tape on mine
Step 4) ...
Step 5) Run box fan for profit

you'd need to build a containment box with louvers of a mesh screen so larger particles would have somewhere to sit else the furnace filter would only catch the really small stuff, the rest falling back into the flow.
Uh, what? Not sure what you just meant, but if I am even close, the fan should suck through the filter, not blow through it.

Originally posted by: Jeff7
Originally posted by: Howard
Step 1) Purchase a box fan (its shape MUST resemble this - e.g. no curves)
Step 2) Purchase a good furnace filter approximately the same size as the fan
Step 3) Attach furnace filter to box fan (mind the orientation for both) - I use tape on mine
Step 4) ...
Step 5) Run box fan for profit
My worry is that that might be too much of a strain on the fan's motor. Those things are likely designed only to be able to fight the inertia of the fan blades and the resistance of free-flowing air. Making it try to suck air through a filter might overheat the motor.
The resistance is pretty low. I built one myself and it works just fine.

filter_fan.jpg
 

0roo0roo

No Lifer
Sep 21, 2002
64,795
84
91
Originally posted by: Howard
Originally posted by: 0roo0roo
Originally posted by: Howard
Step 1) Purchase a box fan (its shape MUST resemble this - e.g. no curves)
Step 2) Purchase a good furnace filter approximately the same size as the fan
Step 3) Attach furnace filter to box fan (mind the orientation for both) - I use tape on mine
Step 4) ...
Step 5) Run box fan for profit

you'd need to build a containment box with louvers of a mesh screen so larger particles would have somewhere to sit else the furnace filter would only catch the really small stuff, the rest falling back into the flow.
Uh, what? Not sure what you just meant, but if I am even close, the fan should suck through the filter, not blow through it.

Originally posted by: Jeff7
Originally posted by: Howard
Step 1) Purchase a box fan (its shape MUST resemble this - e.g. no curves)
Step 2) Purchase a good furnace filter approximately the same size as the fan
Step 3) Attach furnace filter to box fan (mind the orientation for both) - I use tape on mine
Step 4) ...
Step 5) Run box fan for profit
My worry is that that might be too much of a strain on the fan's motor. Those things are likely designed only to be able to fight the inertia of the fan blades and the resistance of free-flowing air. Making it try to suck air through a filter might overheat the motor.
The resistance is pretty low. I built one myself and it works just fine.

filter_fan.jpg

well if it blew through the filter the fan would be the containment box.
as well as really small particles that can be caught by paper filters theres the fuzz you see in vac bags. you need an extension area for that stuff to be built up without just being thrown back out into the air because it can't be contained by the filter.
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
50,419
8
81
While I'm all for home made stuff, that's silly.. :p I mean, it will help.. but it isn't going to do much.

Most furnace filters aren't comparable to even the crappiest air filters. You could get one of the more expensive ones. Look for something that's at least has an efficiency and micron rating..

You will need to attach it to the fan better than that, though, to make it effective. Use duct tape all around it, to make sure it's sealed and all the air goes through it.

It will probably make the fan motor run hotter, but it shouldn't burn it up or be a fire hazard unless the air restriction is fairly significant.
 

dguy6789

Diamond Member
Dec 9, 2002
8,558
3
76
I'm gonna try the fan filter thing and see how that goes and if it doesn't help much I'll just have to shell out for a real one.
 

0roo0roo

No Lifer
Sep 21, 2002
64,795
84
91
Originally posted by: Eli
While I'm all for home made stuff, that's silly.. :p I mean, it will help.. but it isn't going to do much.

Most furnace filters aren't comparable to even the crappiest air filters. You could get one of the more expensive ones. Look for something that's at least has an efficiency and micron rating..

You will need to attach it to the fan better than that, though, to make it effective. Use duct tape all around it, to make sure it's sealed and all the air goes through it.

It will probably make the fan motor run hotter, but it shouldn't burn it up or be a fire hazard unless the air restriction is fairly significant.

well the 3m stuff has a hepa rating i think.

i remember what alton brown used them for...

http://burntlumpia.typepad.com.../04/filipino-tapa.html
box fan jerky!
 

Howard

Lifer
Oct 14, 1999
47,982
10
81
Originally posted by: Eli
While I'm all for home made stuff, that's silly.. :p I mean, it will help.. but it isn't going to do much.

Most furnace filters aren't comparable to even the crappiest air filters. You could get one of the more expensive ones. Look for something that's at least has an efficiency and micron rating..

You will need to attach it to the fan better than that, though, to make it effective. Use duct tape all around it, to make sure it's sealed and all the air goes through it.

It will probably make the fan motor run hotter, but it shouldn't burn it up or be a fire hazard unless the air restriction is fairly significant.
No need to tape all around it. Yes, the air that doesn't go through the filter won't get filtered, but not all the stuff in the air that does go through the filter gets caught in the filter... Get my drift? If he wants, he can get a filter that's bigger than the fan.

I don't see why you think the restriction could be significant at all. Have you never held a furnace filter before?
 

Eli

Super Moderator | Elite Member
Oct 9, 1999
50,419
8
81
Originally posted by: Howard
Originally posted by: Eli
While I'm all for home made stuff, that's silly.. :p I mean, it will help.. but it isn't going to do much.

Most furnace filters aren't comparable to even the crappiest air filters. You could get one of the more expensive ones. Look for something that's at least has an efficiency and micron rating..

You will need to attach it to the fan better than that, though, to make it effective. Use duct tape all around it, to make sure it's sealed and all the air goes through it.

It will probably make the fan motor run hotter, but it shouldn't burn it up or be a fire hazard unless the air restriction is fairly significant.
No need to tape all around it. Yes, the air that doesn't go through the filter won't get filtered, but not all the stuff in the air that does go through the filter gets caught in the filter... Get my drift? If he wants, he can get a filter that's bigger than the fan.

I don't see why you think the restriction could be significant at all. Have you never held a furnace filter before?

I guess taping all around it isn't necessary, but it seems silly not to. I guess I would just be interested in making the device as efficient as possible.

I don't necessarily think it would restrict air flow significantly, I was just saying that it shouldn't be a problem unless it did. The more efficient and lower the micron rating of the filter he gets, the more it will restrict air flow - especially as the filter is used.

Any restriction in air flow through the motor will cause a net temperature increase, but it shouldn't be a big deal unless we're talking barely flowing here.
 

Scouzer

Lifer
Jun 3, 2001
10,358
5
0
lol that box fan idea is really silly. if i visited your house and saw that... you'd be judged as eccentric and cheap.
 

0roo0roo

No Lifer
Sep 21, 2002
64,795
84
91
well no seal means bigger particles not caught would possibly be blown back out where the air leaks.
building an extra extension section box to hold the filter would also give you the option of using a larger filter, more surface area, less resistance to the fan. the box would catch all the particles and hold them. course its more trouble to make but it would be effective.

i did this once with an old home server pc on a small scale with some wood tape and cardboard. figured it would moving air, see what it can catch. it filled the filter box with fluff like a vacuum does its bag, the fluff wasn't compacted, small radial fans don't handle pressure well, but there was a damn lot of it. nutty stuff.
 

Howard

Lifer
Oct 14, 1999
47,982
10
81
Originally posted by: Scouzer
lol that box fan idea is really silly. if i visited your house and saw that... you'd be judged as eccentric and cheap.
Coincidentally, people like you do not number among my friends.
 

dguy6789

Diamond Member
Dec 9, 2002
8,558
3
76
Originally posted by: Howard
Originally posted by: Scouzer
lol that box fan idea is really silly. if i visited your house and saw that... you'd be judged as eccentric and cheap.
Coincidentally, people like you do not number among my friends.

QFT.

 

KingGheedora

Diamond Member
Jun 24, 2006
3,248
1
81
sealing around the edges is a good idea, because if the air through the fan has a path of lower resistance (the path that doesn't go through the filter), then a large amount of the air will take that path and be unfiltered. If you force all the air to go through the filter then your fan will be forced to work harder, but the contraption will be more effective.

I have an air purifier, and the idea is pretty much the same as this. Mine has a pre-filter, which is similar to steel wool, to catch the big stuff, and right after that, there is a HEPA filter, which catches the finer stuff. You might want to do that. My vacuum also does the same thing, steel wool type filter, and then a HEPA certified filter for the smaller stuff.
 

Scouzer

Lifer
Jun 3, 2001
10,358
5
0
Originally posted by: dguy6789
Originally posted by: Howard
Originally posted by: Scouzer
lol that box fan idea is really silly. if i visited your house and saw that... you'd be judged as eccentric and cheap.
Coincidentally, people like you do not number among my friends.

QFT.

i did some googling:

scroll down

he actually tested how effective it was. wow. i withdraw my previous comments. it's really effective! i think i will test this out in the next few days.
 

Jeff7

Lifer
Jan 4, 2001
41,596
19
81
Originally posted by: 0roo0roo
well no seal means bigger particles not caught would possibly be blown back out where the air leaks.
building an extra extension section box to hold the filter would also give you the option of using a larger filter, more surface area, less resistance to the fan. the box would catch all the particles and hold them. course its more trouble to make but it would be effective.

i did this once with an old home server pc on a small scale with some wood tape and cardboard. figured it would moving air, see what it can catch. it filled the filter box with fluff like a vacuum does its bag, the fluff wasn't compacted, small radial fans don't handle pressure well, but there was a damn lot of it. nutty stuff.
Sure, some stuff might get around the edges, but a lot of it will get caught in the filter.
And if dust does get around the sides, it'll go back into circulation, and have another chance to get trapped in the filter.

Interesting, and inexpensive idea.


Originally posted by: Scouzer
I did some googling:

scroll down

he actually tested how effective it was. wow. i withdraw my previous comments. it's really effective! i think i will test this out in the next few days.
Neat link.

I wonder if something like that would work at my parents' house? They've got a wood pellet furnace, and during refueling, sawdust gets thrown out into the air, and when it's opened for cleaning, super-fine ash invariably finds its way into the air.
They've got a small air cleaner/filter unit, but it's fairly low CFM.
A box fan would definitely move a lot more air through a filter.



Howard, I don't suppose you've got a Kill-A-Watt power meter?
I'd still like to see the power consumption of a box fan with and without the filter on it.

 

Howard

Lifer
Oct 14, 1999
47,982
10
81
I don't have a Kill-A-Watt, but let me cut the cord open and then I'll use my $2000 clamp ammeter around one of the power wires to find out the power.

Actually, never mind. I can't do it. :p
 

Jeff7

Lifer
Jan 4, 2001
41,596
19
81
If you were daring, and had access to some good alligator clips, banana plugs, and a multimeter, you could rig up something to test the current flow.

Sure there'd be lots of exposed 120VAC conductors lying about, but that's part of the fun of it. :D




Curses, I've got a Kill-A-Watt and a box fan, but no filter.

 

geno

Lifer
Dec 26, 1999
25,074
4
0
Originally posted by: Scouzer
lol that box fan idea is really silly. if i visited your house and saw that... you'd be judged as eccentric and cheap.

OH NOES!!! NOT JUDGMENT!!!
 

JulesMaximus

No Lifer
Jul 3, 2003
74,541
920
126
I bought one of these a couple years ago. I really only use it when the air quality is really bad like when there are fires.
 

nanette1985

Diamond Member
Oct 12, 2005
4,209
2
0
Okay, I'm really stupid, but I have a box fan and a lot of dust.

Do you put the filter on the side of the fan that blows air out, or the side that air comes in?

Thank you.