6 ms·

You might conclude that the only real option is to buy a positive pressure fresh air system, but this comparison doesn't match my experience. I have no trouble

by sbirch 3y ago

You might conclude that the only real option is to buy a positive pressure fresh air system, but this comparison doesn't match my experience. I have no trouble driving the PM2.5 very close to 0 with a few standalone purifiers in my house (verified with a couple air quality monitors) even during bad wildfire smoke events. I'll grant I live in a modern house which is pretty well sealed, but it's also a question of sizing the purifier to the room's size and drafts. There are some orthogonal advantages and disadvantages though. On the upside, you'll reduce CO2 and other pollutants from inside your house -- it can get quite stuffy when you can't ventilate due to poor outdoor air quality. A downside is that it may also bring in air at a different temperature or humidity than you'd like (though that can also be controlled to some extent with a HRV/ERV.)

ahaucnx 3y ago
I agree, if you have a modern house you could bring down the levels with air purifiers but having no fresh air exchange really makes the house feeling very stuffy and you could get into very high CO2 levels which have its own set of health impacts.
- stinos 3y ago
  but having no fresh air exchange That 'but' isn't a given, modern houses which are properly sealed should have ventilation as well specifically to address that issue. Proper ventilation comes with inlet filters but those usually don't keep out PM<x> so still the purifier will have to do sme more work because of the constant sucking in of polluted air. However, I honestly do not know how common venitlation is already on other continents than mine where it's been made pretty clear by now that sealing a house equals need for ventilation.
coda_ 3y ago
That's impressive... What are you using for purifiers?
- ahaucnx 3y ago
  The positive pressure system is from a local supplier in Thailand and only available in Thailand and China. PM me if you need more information.
  - atombeef 3y ago
    I'm curious about what supplier and system you're using? I'm currently using a bunch of smartair purifier, that gets indoor pm2.5 to close to zero even when it gets really bad outside every year (also in Thailand). But considering installing a positive pressure (ducted) system with HEPA filter due to high co2 levels (tightly sealed house and no ventilation)
    - erkkie 3y ago
      Curious too (also in Thailand), currently using smartair and Ikea Starkwind for PM/VOCs. Looking to design something more integrated with CO2, house cooling, de-humidifying aspects included (controlled by HA). Have you entertained heat exchange systems? Thoughts on the magnitude of impact to aircon?
- nerdbaggy 3y ago
  I use the Alen Air 75i and have no issues getting my PM2.5 to 0 https://alen.com/products/alen-breathesmart-75i-air-purifier?variant=13172054491203 https://alen.com/products/alen-breathesmart-75i-air-purifier...
  - virtuallynathan 3y ago
    That one seems a bit pricey, I think the best I’ve seen for CADR per dollar is the Conway 400(S) or Medify MA-112.
    - nerdbaggy 3y ago
      Yeah they are expensive but the best I have found. The 45i is for like 700 square feet for $400. The nice part about Alen purifiers is the filters last just about a year and lifetime warranty
DANmode 3y ago
What if the goal isn't to reduce measurable air particles, but remove more mold spore "attempts" from adhering to surfaces in your home? Could positive pressure be superior in that case?
- rocqua 3y ago
  Positive pressure does 'one shot' filtering. All air in the house goes through the HEPA filter once. Hence any spores (or other patrickes) that get filtered, get filtered immediately. Though spores (or particles) that make it through the filter get to linger indefinitely. It sounds like a good filter and PPS would meet your goal.
  - FredPret 3y ago
    Particles that get through the HEPA filter will get pushed out of the house by the positive pressure. Unless your house is literally airtight and you never leave
thebigman433 3y ago
What air quality monitors do you use?

by sbirch 3y ago

ahaucnx 3y ago

I agree, if you have a modern house you could bring down the levels with air purifiers but having no fresh air exchange really makes the house feeling very stuffy and you could get into very high CO2 levels which have its own set of health impacts.

stinos 3y ago
but having no fresh air exchange That 'but' isn't a given, modern houses which are properly sealed should have ventilation as well specifically to address that issue. Proper ventilation comes with inlet filters but those usually don't keep out PM<x> so still the purifier will have to do sme more work because of the constant sucking in of polluted air. However, I honestly do not know how common venitlation is already on other continents than mine where it's been made pretty clear by now that sealing a house equals need for ventilation.

coda_ 3y ago

That's impressive... What are you using for purifiers?

ahaucnx 3y ago
The positive pressure system is from a local supplier in Thailand and only available in Thailand and China. PM me if you need more information.
- atombeef 3y ago
  I'm curious about what supplier and system you're using? I'm currently using a bunch of smartair purifier, that gets indoor pm2.5 to close to zero even when it gets really bad outside every year (also in Thailand). But considering installing a positive pressure (ducted) system with HEPA filter due to high co2 levels (tightly sealed house and no ventilation)
  - erkkie 3y ago
    Curious too (also in Thailand), currently using smartair and Ikea Starkwind for PM/VOCs. Looking to design something more integrated with CO2, house cooling, de-humidifying aspects included (controlled by HA). Have you entertained heat exchange systems? Thoughts on the magnitude of impact to aircon?
nerdbaggy 3y ago
I use the Alen Air 75i and have no issues getting my PM2.5 to 0 https://alen.com/products/alen-breathesmart-75i-air-purifier?variant=13172054491203 https://alen.com/products/alen-breathesmart-75i-air-purifier...
- virtuallynathan 3y ago
  That one seems a bit pricey, I think the best I’ve seen for CADR per dollar is the Conway 400(S) or Medify MA-112.
  - nerdbaggy 3y ago
    Yeah they are expensive but the best I have found. The 45i is for like 700 square feet for $400. The nice part about Alen purifiers is the filters last just about a year and lifetime warranty

DANmode 3y ago

What if the goal isn't to reduce measurable air particles, but remove more mold spore "attempts" from adhering to surfaces in your home? Could positive pressure be superior in that case?

rocqua 3y ago
Positive pressure does 'one shot' filtering. All air in the house goes through the HEPA filter once. Hence any spores (or other patrickes) that get filtered, get filtered immediately. Though spores (or particles) that make it through the filter get to linger indefinitely. It sounds like a good filter and PPS would meet your goal.
- FredPret 3y ago
  Particles that get through the HEPA filter will get pushed out of the house by the positive pressure. Unless your house is literally airtight and you never leave

thebigman433 3y ago

What air quality monitors do you use?