Testing My El Cheapo Particle Meter
Posts
Additional testing of DIY MERV 13 and indoor air quality Australia Day Long Weekend
As the smoke rolled in on Sunday night I put my particle counter outside and watched it peak at 170 PM2.5 outside.
Should I run my ducted AC to filter the smoke out of the air?
Is it a good idea to filter the smoke by running your ducted AC or heater on fan mode? TLDR; No, but with an $11 air purifier running in each room mine is fine
Why isn't my purifier achieving its rated room size?
It's 70 inside and rising. As my family move into a small room I wonder why isn't my purifier working?
Simulating Indoor Air Quality
To see how changing some parameters affects indoor air quality I have created a basic spreadsheet simulation.
Improving air quality of a ducted reverse cycle air conditioner
As I run my ducted AC I watch the PM2.5 count rise, 50, 70, 100.
Convert a fan into a DIY Air Purifier with an $11 MERV filter
Air quality in Canberra is terrible due to bushfires. I'm often surprised how high the inside readings are in my house when it doesn't look or smell bad. While you cannot see the smoke it is there.
Why air flow matters more than filter rating
After lots of reading about different filters and how effective they are at filtering different particle sizes I have come to an unexpected conclusion, the rating doesn't matter that much. What really matters is your air changes per hour , that is how many times per hour the air is filtered.
Air Changes per Hour (ACH)
Testing by CSIRO found that a typical ACH of the tested houses was 0.77 ACH, or 15.4 ACH50. The Passive House standard requires air tightness so that there will be less than 0.6 ACH50 with a pressure difference between inside and outside of 50 Pa. Under normal conditions this should mean a ACH of 0.03. 0.5 ACH50 - 0.03 ACH - Passive House, very tight 3 ACH50 - 0.15 ACH - A good aim - Just Right and Airtight 15.4 ACH50 - 0.77 ACH - Average in CSIRO study Note I am using a conversion of 1 ACH50 = 20 ACH based on a statement by CSIRO. How to measure ACH Blower door test References Air changes per hour - Wikipedia How Much Air Leakage in Your Home Is Too Much?