# HEPA filters



## begreen (Dec 19, 2020)

What are folks using for a HEPA filter? This thread is for reviews on what you are using and how well it works. Please include the make and model and how large an area is being covered. Extra points for describing how often it needs cleaning or filter changing and how quiet it is, or isn't.


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## begreen (Dec 19, 2020)

Right now we have been using our central heat pump systems filters. There are a pleated 1" prefilter and a 4" merv13 filter. During the late summer wildfire smoke, the system ran 24/7 for about a week. The filter was new about a year ago. Normally the 4" lasts 2-3 yrs, but 2020 has been anything but normal. I need to go down and check the filters and see if they need replacing. I keep a spare on hand.


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## DuaeGuttae (Dec 20, 2020)

We actually have three different central AC/gas furnaces in our house, and at this time of year we are running 1" MERV12 filters, I believe, but the systems themselves aren't running much at this time of year. It's actually very high allergy season this month and next with cedar pollen.  I've been allergic to all sorts of stuff all my life but never had I suffered the way I do from cedar pollen down here.  We try to change our filters on the 3 to 6 month timeframe, depending on how much use each system sees.  We aren't running the central systems very much right now, though, so we don't really rely on it for air purification.

We also run a number of stand-alone air purifiers in the house.  For many years the only one we used was a large Blueair purifier from Costco.  It uses three pricey filters that we change once a year, but when we lived in smaller homes with just one A/C/heat system, we used it to cover the entirety of the house.  We bought it when our first child was an infant and was having skin rashes during pollen season.  The doctor recommended Benadryl and hydrocortisone, but we tried the air purifier first, and the problems cleared up.  We run it pretty much constantly on its "HEPA silent" setting, and it is really quiet.  It lives in our large open area (four rooms in one) where we spend most of our waking hours.

Now that we live in a larger house with some very tough allergy seasons, we have three room-sized air purifiers, one for each bedroom.  I think they are "Germ Guardian" brand.  I am more faithful about running mine in my bedroom than my children are (they make some noise), but when my kids start sniffling, I'll usually find that someone has turned a purifier off.  I turn it back on, ask them to leave it, and symptoms improve in the next couple of days.

We have no pets, but I'm also not great about vacuuming and dusting all the surfaces in my home.  I will occasionally vacuum my filters to extend their life, but they obviously get a lot of stuff out of our air.  I've tossed some pretty nasty filters over the years.


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## Highbeam (Dec 20, 2020)

Here’s a photo of mine. We call it the monster. I vacuum the filter and prefilters every few months and change the big honking car style air filter every couple of years. I don’t know if it’s worth the money. 
	

		
			
		

		
	





It’s very quiet and picks up speed and noise if it senses particulates.


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## begreen (Dec 20, 2020)

Highbeam said:


> Here’s a photo of mine. We call it the monster. I vacuum the filter and prefilters every few months and change the big honking car style air filter every couple of years. I don’t know if it’s worth the money.
> 
> It’s very quiet and picks up speed and noise if it senses particulates.


What is the make and model? How did it work out during the wildfire smoke?


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## Highbeam (Dec 20, 2020)

begreen said:


> What is the make and model? How did it work out during the wildfire smoke?


It’s a sharp fpa80u. As I recall it cost like 150$. Very quiet on low, actually can’t even hear it. It gets pretty grossly dirty so it must be doing something. No ductwork or air conditioning in this old house. 

We manually cranked it up to medium during the fires. Not sure if it helped. We were laying low and are pretty healthy otherwise.


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## EbS-P (Dec 21, 2020)

4 kids and a big poodle and not a rug or carpet in the house. We don’t live in a dusty climate.

I use these for hvac filters. Being limited to 1” thick filters I feel that anything higher is just too restrictive. I use a washable 5$ scotchbrite pre filter. I can go about an entire cooling season on one filter. And they don’t see much use in the winter.

Nordic Pure 20x30x1 MERV 12 Pleated AC Furnace Air Filters 6 Pack Amazon product

We run two of these. They are very quite on low. I use wa washable window ac prefilter they have the charcoal filters too. I wash the hepa filters every time it tells me to change them. First filter lasted 4 years. We call them the fart detectors. On a real smokey reload they ramp up to high and can be loud. But most of the time they stay on low

Winix 5500-2 Air Purifier with True HEPA, PlasmaWave and Odor Reducing Washable AOC Carbon Filter Amazon product

You can spend a lot of money on filtration but this seems to work reasonably well for not a huge up front and consumable cost.
Evan


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## SpaceBus (Dec 21, 2020)

I got one of these(LINK) back in 2017 when we lived in an RV. After moving up here to Maine and burning wood full time I got a second one. The unit says it is rated for 129 sqft, so a small bedroom or study, but it does fine in our open downstairs or in a reasonably sized bedroom. Our house is only 1,200 sqft, so I would suggest a different model for larger rooms/areas. The filters last about 3-6 months depending on use. I buy several filters and pre-filters at a time. With three dogs in the house, we have a lot of dog hair and vacuum frequently with a HEPA equipped stick vac and that helps keep the filters going longer. Even though we vacuum frequently I still find dog hair stuck to the air intake of the air filter after running it for a few days. There is a definite improvement in air quality even running it on a nearly silent mode. My cookstove had a momentary draft reversal from a gust when lighting this morning and my wife didn't even notice since the air filter was running. 1000% worth it! Even taking out the full ash pan, cleaning the ash out of the firebox, and taking that outside did not result in a dusty house due to the air filter. 

Some kind of air filter is a must when burning wood. Especially in the winter when the house doesn't open as often.


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## Highbeam (Dec 21, 2020)

EbS-P said:


> 4 kids and a big poodle and not a rug or carpet in the house. We don’t live in a dusty climate.
> 
> I use these for hvac filters. Being limited to 1” thick filters I feel that anything higher is just too restrictive. I use a washable 5$ scotchbrite pre filter. I can go about an entire cooling season on one filter. And they don’t see much use in the winter.
> 
> ...




You wash the HEPA filter? I thought they had to be replaced like a paper automotive air filter. 

Your winix is almost certainly the same thing as my sharp.


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## Brian26 (Dec 21, 2020)

I have an old school analog Dwyer Mark II manometer and measure the pressure drop on my 16x25x1 filters on my forced air furnace. I tested all the big box store filters in my size. The winner was suprisngly a Filtrete 1900 Merv 13 with a pressure drop of .25 wc. The cheap pleated filters were actually more restrictive like those Home Depot FPR 4 filters. The ECO washable filters was even worse.

This units is worth it as you can truly see your filter load up. You just connect the air hoses before and after the filter and zero it out with no filter in. You can also use it to measure your ductwork static pressure and CFM.

I discovered most filters easily last way beyond the recommended 3 month change.


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## Highbeam (Dec 21, 2020)

Filtering ability should only improve as they plug up so long as you’re getting enough air through.


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## begreen (Dec 21, 2020)

The Winix 5500 got good reviews an is a nice value.








						The Best Air Purifier
					

Clear the air—and maybe even improve your health—with a dedicated filter for any room in your home.




					www.nytimes.com
				




I see Costco sells a similar Winix C545 for $130. Amazon lists it for $189.


			https://www.costco.com/winix-true-hepa-4-stage-air-purifier-with-wi-fi-and-additional-filter.product.100662892.html


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## Ctwoodtick (Dec 21, 2020)

I just today got the Hathaspace Hepa purifier. Set it up already and running in stove room. It has the feature where the fan runs quicker with increased dust, etc. I was glad to see my first stove reload did not put it into a higher speed!


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## Dataman (Dec 21, 2020)

I have Two Atlas Tower Filters (https://www.atlasairpurifier.com/).   They do great job.  I clean the with Air Compressor about every 60 days.   In the Hall we have couple of Box Fans with 20x20x1 Furnace Filter, again Air Compresser.  Swap out every year.  House has Heat Pump and Honeywell  F300E Electronic Air Cleaners.   Every 90 days I take them out and clean them with Soap and Water.    In Winter since Pellet Stove is working (Harmon XXV) they don't get much use (Been very warm last couple days).   Heat Pump will take over in the day when over 30f.   Filters help catch the Grey Dust from Humidifiers.


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## woodgeek (Dec 22, 2020)

When my kids were little I did the standalone HEPA thing, never sure it did much tbh.

I have been buying the Filtrete 'Ultimate Allergen' 1" filters for my HVAC return (HP+AC) for over a decade.  They are MERV 13.  With that and the airsealing the dust and allergens in my house are MUCH reduced relative to before, with no airsealing and hydronic baseboards. 

My HVAC dude told me to only use the (see through) floss filters, because 'pressure', but I measured the pressure drop across the filter (  ) both new and at end of life and it was well below specs from the blower manufacturer (Goodman).  Well engineered 'depth filters' which are stacks of sticky fibers, are not like a 'membrane filter' with pores of a certain size, like a sieve, and the pressure drop does not need to be high to get high capture.  A plus, I reckon my ducts stay a lot cleaner inside.

I would trust anything in the 3M Filtrete line to NOT break my HVAC blower, contra what an HVAC tech would tell me.

Its not HEPA, but I figure it makes up particle removal on the volume (cfm).  If I needed more filtration, I would do standalone on top of the HVAC filter, on a closed room basis


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## Brian26 (Dec 22, 2020)

woodgeek said:


> When my kids were little I did the standalone HEPA thing, never sure it did much tbh.
> 
> I have been buying the Filtrete 'Ultimate Allergen' 1" filters for my HVAC return (HP+AC) for over a decade.  They are MERV 13.  With that and the airsealing the dust and allergens in my house are MUCH reduced relative to before, with no airsealing and hydronic baseboards.
> 
> ...



I measured the pressure drop of every box store filter and the Filtrete 1900 merv 13 absolutely crushed every other filter. It had the lowest pressure drop and even when the thing was loaded up it still had good airflow.

California did some sort of air study and the 1 inch Filtrete merv 13 actually had better airflow then even some of the 2-4 inch filters.  I'll try and dig up the study.


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## Brian26 (Dec 22, 2020)

I have had an I-Wave bi-polarizaton ionizer on my forced air furnace as well for a few years. The technology is widely used in hospitals. It made a huge difference in indoor air quality. I recently had a bad draft on the woodstove and 10 mins of my blower running completely eliminated all the smoke odor. 






						iWave-R Air Ionization System Nu-Calgon
					






					www.nucalgon.com


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## SpaceBus (Dec 22, 2020)

We don't have, nor want, a forced air system, so we depend on the standalone units in the winter. It's all pretty futile when our dogs have to go in and out all day, plus doing other animal related chores. Having a window open in the summer might as well negate running a filter for 24 hours. On the bright side the outside air is pretty decent here so we don't mind.


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## begreen (Dec 29, 2020)

Well, this has been an interesting experience. We got the Winix and have had it running for a few days now. It has indicated that the air quality is good. The wood stove is in 24/7 mode. Nothing I have done with the woodstove has changed the Winix status. However tonight, once my wife started cooking, the status went to orange. I'll be curious to see how soon it takes to return to blue.


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## Highbeam (Dec 30, 2020)

Did you expect your woodstove to cause an air quality problem? Nothing I do with my stove has caused the sensor to indicate anything other than good. Sweeping the floors sure upsets it.


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## SpaceBus (Dec 30, 2020)

I think it has been mentioned elsewhere that cooking does more to ruin air quality than most other activities. Cooking meat in a pan is especially bad for VOCs.


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## DBoon (Jan 2, 2021)

SpaceBus said:


> I think it has been mentioned elsewhere that cooking does more to ruin air quality than most other activities. Cooking meat in a pan is especially bad for VOCs.


It would be good to know the comparison of wood stove (me) versus cooking (wife) considering the histrionics I get whenever a mild amount of smoke enters the room from the wood stove compared to the smoke my wife generates some days when cooking on an electric range (I will be looking forward to the new house with the better range hood and an HRV with HEPA filter).


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## begreen (Jan 2, 2021)

Our unit continues to stay in the blue with an occasional blip when cooking something that puts volatiles into the air. My wife found this out while sauteéing after adding some wine to the pan and it went orange for a few minutes. 
Another interesting thing happened on New Year's Eve, right before midnight. The unit went orange for about 10-15 minutes. All I can figure is that smoke must have increased outside due to fireworks. Nothing had changed inside the house.


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## semipro (Jan 4, 2021)

woodgeek said:


> My HVAC dude told me to only use the (see through) floss filters, because 'pressure', but I measured the pressure drop across the filter (  ) both new and at end of life and it was well below specs from the blower manufacturer (Goodman). Well engineered 'depth filters' which are stacks of sticky fibers, are not like a 'membrane filter' with pores of a certain size, like a sieve, and the pressure drop does not need to be high to get high capture. A plus, I reckon my ducts stay a lot cleaner inside.
> 
> I would trust anything in the 3M Filtrete line to NOT break my HVAC blower, contra what an HVAC tech would tell me.


Good call questioning your HVAC guy.
Squirrel cage blowers on air handlers are centrifugal rather than positive displacement fluid pumps.  The power required to run them actually goes down as you restrict the inlet/outlet - the opposite of a positive displacement pump.  The only way a clogged filter can cause a blower motor failure is if the flow is so restricted that the motor overheats which is really unlikely given that the power usage goes way down too.
That said, of course a clogged filter degrades the performance of the system as far as moving air and cooling/heating.

Edit: thinking about his a bit more, I guess that blower motors operating with high levels of flow restriction could overspeed and fall apart or damage the bearings.


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## sloeffle (Jan 4, 2021)

I noticed during the winter when I am burning wood, my basement gets dusty from the wood, and wood ash. I'm thinking about putting a HEPA air purifier in my basement. My basement is only 800sq ft so I'm assuming I probably don't need the biggest unit out there. 

Can anybody recommend a model that they have used and liked ? Any idea how much energy one of these unit uses ? I'm a Toyota / Honda kind of guy, so preferably something that isn't going to break the bank and is fairly cheap to buy filters ( or washable ) for.


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## semipro (Jan 4, 2021)

One thing I've noticed is that air filtration systems are like printers in that the lifetime ownership expense is mostly in the consumables.  Check the price of replacement filters before you commit.


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## Highbeam (Jan 4, 2021)

Be very sure that the filter is actually washable. That’s weird. Like washing a regular automotive air filter.


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## SpaceBus (Jan 5, 2021)

Highbeam said:


> Be very sure that the filter is actually washable. That’s weird. Like washing a regular automotive air filter.


Many aftermarket and performance filters use fabric rather than paper and are washable. I assume these cloth filters when new are probably not as good at filtering, but after they have gotten a bit dirty they should be just as good as any paper filter. Many folks like the K&N oiled filters, but they have consistently show to let a dangerous, for your engine, amounts of particulates through the filter.


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## begreen (Jan 6, 2021)

The Winix we just got has 3 filters - a washable prefilter, much like a dryer lint filter, a charcoal filter that ?might? be washable, and the pleated Hepa filter that is not washable.


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## Highbeam (Jan 7, 2021)

begreen said:


> The Winix we just got has 3 filters - a washable prefilter, much like a dryer lint filter, a charcoal filter that ?might? be washable, and the pleated Hepa filter that is not washable.



Same as mine. That HEPA filter is expensive.


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## LoraSanchez (Jan 13, 2021)

EbS-P said:


> 4 kids and a big poodle and not a rug or carpet in the house. We don’t live in a dusty climate.
> 
> I use these for hvac filters. Being limited to 1” thick filters I feel that anything higher is just too restrictive. I use a washable 5$ scotchbrite pre filter. I can go about an entire cooling season on one filter. And they don’t see much use in the winter.
> 
> ...



Thanks for the available links , I won't have to search long.


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## mcdougy (Feb 5, 2021)

https://www.cbc.ca/news/marketplace/how-clean-is-the-air-in-your-home-1.5900697


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## begreen (Feb 5, 2021)

Highbeam said:


> Same as mine. That HEPA filter is expensive.


Where are you buying the replacement filter?


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## begreen (Feb 5, 2021)

I just replaced our heat pump's filters. There is a 1" MERV8  prefilter and a 4" MERV13 filter.  Most years the system doesn't run during the dead of winter as we are using the wood stove. But last summer I ran the fan continuously on low speed during a period of serious smoke from wildfires. Normally the 4" filter goes about 3 yrs and is only slightly dirty at that point.  This time, with 15 months on it,  it was a dark gray   Well, at least it did its job.


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## Highbeam (Feb 5, 2021)

begreen said:


> Where are you buying the replacement filter?


Amazon. They last for quite a while but it’s painful to replace them.


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## mcdougy (Feb 6, 2021)

Is an $800 purifier best to clean your home's air? Marketplace tested 5 top brands and their claims
					






					www-cbc-ca.cdn.ampproject.org
				












						The 7 Best High CADR Air Purifiers Review in 2020 (>310 cfm)
					

In this article, we talk about the CADR ratings and the 7 best high CADR air purifiers, including their top features, pros, and cons.




					reviewsofairpurifiers.com


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## Brian26 (Feb 11, 2021)

I ended up buying a Winix 5500-2. I was curious on the electrical consumption and hooked up my killawatt meter to it. On auto/low fan it uses only 5 watts!


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