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arakboss

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Wife wants to put together an air purifier or three and she was looking at some box fan contraption idea online that uses furnace size hepa filters. Evidently she is not the only one as the filters appear to be sold out everywhere locally. We are headed out now to see what we can find that is HEPA rated. Please post any ideas you have for making something at home, hopefully on the cheap. We have some Kirby hepa vaccum bags we are thinking about sacrificing to rig up on a portable AC.
 

jbett98

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I went to a commercial air filter business yesterday and bought a charcoal infused air filter for my gas furnace.
They said that they have never been busier and were closing down at noon, so I had to hustle over there before they closed.
They're located on SE 10th & Sherman. I also borrowed an old Honeywell room unit heppa filter which had a new filter installed a little while ago.
The best thing I did was block all the bathroom fan vents, and the furnace make up air vents that are open to the attic.
 
For the bedroom:

https://www.amazon.com/Honeywell-HE...26629&sprefix=Honeywell+,undefined,424&sr=8-6

Merv 11 on a box fan should help quite a bit:


Currently we have merv 13 running on a box fan (what was available at the time), cuts down a bit whole house. Marked difference between inside and outside!

Merv 11 is better than 13...

Could also be that we have another small Hepa filter in the living room tho, dunno.

Have always run a few Hepa filters, mostly to cut back on allergins.
 
Wife wants to put together an air purifier or three and she was looking at some box fan contraption idea online that uses furnace size hepa filters. Evidently she is not the only one as the filters appear to be sold out everywhere locally. We are headed out now to see what we can find that is HEPA rated. Please post any ideas you have for making something at home, hopefully on the cheap. We have some Kirby hepa vaccum bags we are thinking about sacrificing to rig up on a portable AC.
Do you have a central air furnace that you can set to run the fan in recirc mode?

I installed a Outside Air filter on the return air plenum just upstream of the main air filter. It’s collecting quite a bit of fine dust and supplying enough OSA to the house to keep the space slightly positive relative to the outside environment. This keeps smoke smells from entering the house.

If your window shaker AC is like any I’ve had in the past, it is leaky and since homes are usually negative, smoke/air/dust will enter at that point.

Edited to add, my garage is vented with a 24x24x4” deep filter and that is where the OSA filter gets it’s makeup air.

AD3DBEB1-F1D2-4CE9-B855-2CBA7AC63B59.jpeg
 
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arakboss

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Do you have a central air furnace that you can set to run the fan in recirc mode?

I installed a Outside Air filter on the return air plenum just upstream of the main air filter. It’s collecting quite a bit of fine dust and supplying enough OSA to the house to keep the space slightly positive relative to the outside environment. This keeps smoke smells from entering the house.

If your window shaker AC is like any I’ve had in the past, it is leaky and since homes are usually negative, smoke/air/dust will enter at that point.

View attachment 748628
nope. we have baseboard heat. nice filter mod though
 

arakboss

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Here is attempt #1. We installed HEPA Vacuum bag material on portable AC intake ports. We are running it in fan mode for this purpose. It cut down on airflow output by well over 50% but that means it's working in my mind. I'll have to monitor the unit to make sure the fan motor doesn't overheat. So far so good.

20200912_094119.jpg

20200912_094151.jpg
 
Here is attempt #1. We installed HEPA Vacuum bag material on portable AC intake ports. We are running it in fan mode for this purpose. It cut down on airflow output by well over 50% but that means it's working in my mind. I'll have to monitor the unit to make sure the fan motor doesn't overheat. So far so good.

View attachment 748629

View attachment 748630
Not to be a debbie downer, but those portable AC units do two things:
(1) Recirculate to interior home air across the evaporator coil which cools the air
(2) Now the bad part: The condenser side coil where all the heat from the evap coil is transferred has a fan that blows across the condenser coil and exhausts that heat to the outside atmosphere. Now THE BIG RED PILL HERE is all that air being exhausted comes from INSIDE your home, and since it’s exhausting a few hundred CFM, it draws your home negative to the adjacent outside atmosphere. That means while you are cooling some recirc air, you are dragging in a lot of contaminated non conditioned air from exhaust ducts and all kinds of little leaks you would never know existed.

All this assuming you have it setup correctly to exhaust the heat to outside.
 

arakboss

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Not to be a debbie downer, but those portable AC units do two things:
(1) Recirculate to interior home air across the evaporator coil which cools the air
(2) Now the bad part: The condenser side coil where all the heat from the evap coil is transferred has a fan that blows across the condenser coil and exhausts that heat to the outside atmosphere. Now THE BIG RED PILL HERE is all that air being exhausted comes from INSIDE your home, and since it’s exhausting a few hundred CFM, it draws your home negative to the adjacent outside atmosphere. That means while you are cooling some recirc air, you are dragging in a lot of contaminated non conditioned air from exhaust ducts and all kinds of little leaks you would never know existed.

All this assuming you have it setup correctly to exhaust the heat to outside.
Yeah we disconnected the exhaust from the window. The unit is currently running on fan mode, so it's only recirculating inside air through the HEPA bags we taped on intake ports. When we had the unit hooked up for AC use with exhaust hose directed outside it was definitely mixing air from outside. We saw a huge improvement inside after disconnecting exhaust hose and sealing window back up.
 
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I hear you. Fortunately/unfortunately for us, mrs dobeman suffers from occasional mild asthma so we purchased IQAir HEPA/VOC high end machines for the house - 3 of them. Not cheap but the mrs has to breath. They are life savers right now with all the smoke. Needless to say, we can't have windows open especially now. Would hate think what we would do otherwise. She would have to wear N95 or P100 mask all the time.
 
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Plug your foundations vents.

Ensure your attic space is well sealed from your indoor space. As well as all doors and windows.

Don’t open your garage. Don’t open doors.

Saran Wrap windows at seals if needed. Duct tape works too but is messier to remove.

Filtering your air is one thing, keeping it from getting in is another.
 

Ura-Ki

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We have 4 middle range HEPA filter fans running here, we have had them for about 6 years an they do a good job! Like was pointed out above, block your bathroom vents and fans, that will really help, and check your filters often! We also have a pretty good heat pump that maintains a slight over pressure inside the house which really cuts down on the smoke/ash, especially with three dogs coming and going out side through out the day! Our vacuum cleaner is also HEPA equipped, and manages to grab a lot of what the dogs do bring in with them!
 
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