@nathventilation.bsky.social
No one guesses if their kid has a fever
— they measure it.
Indoor air quality deserves the same
Low Cost Sensors are becoming accessible to more families
— they measure it.
Indoor air quality deserves the same
Low Cost Sensors are becoming accessible to more families
August 16, 2025 at 1:27 PM
No one guesses if their kid has a fever
— they measure it.
Indoor air quality deserves the same
Low Cost Sensors are becoming accessible to more families
— they measure it.
Indoor air quality deserves the same
Low Cost Sensors are becoming accessible to more families
In the DIY air purifier community, a bold theory circulates: sufficiently reducing air velocity through MERV 13 filters would achieve filtration rates close to 100%, comparable to HEPA filters.
Why MERV 13 Filters
Don’t Become HEPA at Low Velocity
medium.com/@levangelist...
Why MERV 13 Filters
Don’t Become HEPA at Low Velocity
medium.com/@levangelist...
Why MERV 13 Filters
Don’t Become HEPA at Low Velocity
In the DIY air purifier community, a bold theory circulates: sufficiently reducing air velocity through MERV 13 filters would achieve…
medium.com
August 1, 2025 at 12:37 AM
In the DIY air purifier community, a bold theory circulates: sufficiently reducing air velocity through MERV 13 filters would achieve filtration rates close to 100%, comparable to HEPA filters.
Why MERV 13 Filters
Don’t Become HEPA at Low Velocity
medium.com/@levangelist...
Why MERV 13 Filters
Don’t Become HEPA at Low Velocity
medium.com/@levangelist...
V-Plex air purifiers — DIY purifiers with internal V-shaped filters — are gaining popularity. But two important issues are often overlooked: sacrificed internal volume (the transition chamber) and uncertain airflow paths.
medium.com/@levangelist...
medium.com/@levangelist...
July 30, 2025 at 10:33 PM
V-Plex air purifiers — DIY purifiers with internal V-shaped filters — are gaining popularity. But two important issues are often overlooked: sacrificed internal volume (the transition chamber) and uncertain airflow paths.
medium.com/@levangelist...
medium.com/@levangelist...
If you truly want to know an air purifier CADR, it’s better to measure it in a test chamber. This method is far more reliable than estimation using an anemometer — especially when using filters that haven’t been independently tested or have shown disappointing results.
medium.com/@levangelist...
medium.com/@levangelist...
Estimating CADR with an anemometer is often misleading
It’s better to measure than to guess
The Clean Air Delivery Rate (CADR) is a key metric for evaluating the effectiveness of an air purifier. It combines the airflow rate (in…
medium.com
July 29, 2025 at 1:40 AM
If you truly want to know an air purifier CADR, it’s better to measure it in a test chamber. This method is far more reliable than estimation using an anemometer — especially when using filters that haven’t been independently tested or have shown disappointing results.
medium.com/@levangelist...
medium.com/@levangelist...
Reposted
We’ve co-signed @Protectbc.bsky.social’s open letter to Prime Minister @mark-carney.bsky.social, outlining opportunities to prevent Covid-19 and other airborne health risks (e.g., measles, wildfire smoke) and invest in long Covid research.
covidsociety.ca/news/open-le...
covidsociety.ca/news/open-le...
June 25, 2025 at 3:28 PM
We’ve co-signed @Protectbc.bsky.social’s open letter to Prime Minister @mark-carney.bsky.social, outlining opportunities to prevent Covid-19 and other airborne health risks (e.g., measles, wildfire smoke) and invest in long Covid research.
covidsociety.ca/news/open-le...
covidsociety.ca/news/open-le...
TL;DR: Asking “What air purifier is best for cat allergens?” is like asking “What car is best for carrying computer equipment?” You’re missing the point entirely. Filters don’t care what they’re capturing — only particle size matters.
medium.com/@levangelist...
medium.com/@levangelist...
Cat Allergens, Smoke, Dust…
the Filter Doesn’t Care: Only Particle Size Matters
medium.com
July 20, 2025 at 12:52 PM
TL;DR: Asking “What air purifier is best for cat allergens?” is like asking “What car is best for carrying computer equipment?” You’re missing the point entirely. Filters don’t care what they’re capturing — only particle size matters.
medium.com/@levangelist...
medium.com/@levangelist...
Do We Give Startups A Free Pass On Ethical Behavior?
Startups tended to benefit from a kind of halo effect, where their transgressions were viewed more charitably than those of the larger firms.
www.forbes.com/sites/adigas...
Startups tended to benefit from a kind of halo effect, where their transgressions were viewed more charitably than those of the larger firms.
www.forbes.com/sites/adigas...
Do We Give Startups A Free Pass On Ethical Behavior?
We increasingly want companies to not only deliver great products and services but to do so in an ethical way, but new research suggests that we don't hold startups to the same high standards.
www.forbes.com
July 13, 2025 at 11:40 PM
Do We Give Startups A Free Pass On Ethical Behavior?
Startups tended to benefit from a kind of halo effect, where their transgressions were viewed more charitably than those of the larger firms.
www.forbes.com/sites/adigas...
Startups tended to benefit from a kind of halo effect, where their transgressions were viewed more charitably than those of the larger firms.
www.forbes.com/sites/adigas...
Reposted
At See The Air, I am always excited to share innovative approaches to improving indoor air quality. Today, I am highlighting some fantastic articles by Nathalie Roussy that delve into the world of DIY ventilation with her in-depth work on the FantaMix.
seetheair.org/2025/07/10/i...
seetheair.org/2025/07/10/i...
Introducing FantaMix: An Innovative DIY Ventilation Solution
At See The Air, I am always excited to share innovative approaches to improving indoor air quality. Today, I am highlighting some fantastic articles by Nathalie Roussy that delve into the world of …
seetheair.org
July 10, 2025 at 9:50 AM
At See The Air, I am always excited to share innovative approaches to improving indoor air quality. Today, I am highlighting some fantastic articles by Nathalie Roussy that delve into the world of DIY ventilation with her in-depth work on the FantaMix.
seetheair.org/2025/07/10/i...
seetheair.org/2025/07/10/i...
Open-source DIY quiet HRV for apartments — under $300 with a MERV13 filter.
No ads, no paywall.
Guide here: medium.com/@levangelist...
#DIY #Ventilation #MERV13 #AirQuality #OpenSource
No ads, no paywall.
Guide here: medium.com/@levangelist...
#DIY #Ventilation #MERV13 #AirQuality #OpenSource
AccordFlow: a quiet, filtered DIY HRV — guide to building it
This text is part of a series of articles dedicated to ductless HRVs.
medium.com
July 5, 2025 at 1:35 PM
Open-source DIY quiet HRV for apartments — under $300 with a MERV13 filter.
No ads, no paywall.
Guide here: medium.com/@levangelist...
#DIY #Ventilation #MERV13 #AirQuality #OpenSource
No ads, no paywall.
Guide here: medium.com/@levangelist...
#DIY #Ventilation #MERV13 #AirQuality #OpenSource
🧵Thread on Ethics
1/ Business ethics start from the very beginning.
A startup without ethics will never have any.
Ethics should be a priority and must be reflected in actions.
Beware of the “Fake it until you make it” mentality.
1/ Business ethics start from the very beginning.
A startup without ethics will never have any.
Ethics should be a priority and must be reflected in actions.
Beware of the “Fake it until you make it” mentality.
July 1, 2025 at 2:17 PM
🧵Thread on Ethics
1/ Business ethics start from the very beginning.
A startup without ethics will never have any.
Ethics should be a priority and must be reflected in actions.
Beware of the “Fake it until you make it” mentality.
1/ Business ethics start from the very beginning.
A startup without ethics will never have any.
Ethics should be a priority and must be reflected in actions.
Beware of the “Fake it until you make it” mentality.
I just published on medium
How Much Heat Does Your HRV Really Recover?
A DIY Protocol for Measuring Sensible Heat Recovery
medium.com/@levangelist...
How Much Heat Does Your HRV Really Recover?
A DIY Protocol for Measuring Sensible Heat Recovery
medium.com/@levangelist...
How Much Heat Does Your HRV Really Recover?
A DIY Protocol for Measuring Sensible Heat Recovery
This is the protocol I used to measure the percentage of sensible heat recovery of the Purifresh and three DIY HRVs — shared here as an…
medium.com
June 25, 2025 at 5:20 PM
I just published on medium
How Much Heat Does Your HRV Really Recover?
A DIY Protocol for Measuring Sensible Heat Recovery
medium.com/@levangelist...
How Much Heat Does Your HRV Really Recover?
A DIY Protocol for Measuring Sensible Heat Recovery
medium.com/@levangelist...
🧵
1/I'll be opening my private test chamber for air purifiers this summer or early fall (located in the Montreal area, Canada). If you have a machine you consider 'super good' and wish to get a CADR measurement, you can contact me via direct message. I will do my best to consider every request.
👇
1/I'll be opening my private test chamber for air purifiers this summer or early fall (located in the Montreal area, Canada). If you have a machine you consider 'super good' and wish to get a CADR measurement, you can contact me via direct message. I will do my best to consider every request.
👇
June 24, 2025 at 1:44 PM
🧵
1/I'll be opening my private test chamber for air purifiers this summer or early fall (located in the Montreal area, Canada). If you have a machine you consider 'super good' and wish to get a CADR measurement, you can contact me via direct message. I will do my best to consider every request.
👇
1/I'll be opening my private test chamber for air purifiers this summer or early fall (located in the Montreal area, Canada). If you have a machine you consider 'super good' and wish to get a CADR measurement, you can contact me via direct message. I will do my best to consider every request.
👇
i just published the DIY Noise Protocol — A Simplified Method to Measure Sound Power of Air Purifiers and HRVs at Home medium.com/@levangelist...
DIY Noise Protocol —
A Simplified Method to Measure Sound Power of Air Purifiers and HRVs at Home
The protocol I developed to measure the noise of my air purifiers and HRVs,
shared here as an open and accessible method
to estimate…
medium.com
June 21, 2025 at 1:20 PM
i just published the DIY Noise Protocol — A Simplified Method to Measure Sound Power of Air Purifiers and HRVs at Home medium.com/@levangelist...
1/
Just published the full FantaMix Review — as promised after the open-source build guide.
A tested, DIY system for HEPA-filtered outdoor air — no ducts, no extraction, and under $200 to build.
Perfect timing: wildfire season has started in Canada.
🧵👇
Just published the full FantaMix Review — as promised after the open-source build guide.
A tested, DIY system for HEPA-filtered outdoor air — no ducts, no extraction, and under $200 to build.
Perfect timing: wildfire season has started in Canada.
🧵👇
June 8, 2025 at 6:34 PM
1/
Just published the full FantaMix Review — as promised after the open-source build guide.
A tested, DIY system for HEPA-filtered outdoor air — no ducts, no extraction, and under $200 to build.
Perfect timing: wildfire season has started in Canada.
🧵👇
Just published the full FantaMix Review — as promised after the open-source build guide.
A tested, DIY system for HEPA-filtered outdoor air — no ducts, no extraction, and under $200 to build.
Perfect timing: wildfire season has started in Canada.
🧵👇
Just published:
Build the FantaMix — fresh filtered air at home, no exhaust, under $200.
Open-source DIY guide (60 pages, step-by-step).
🧰 HEPA + partial heat recovery
medium.com/@levangelist...
Build the FantaMix — fresh filtered air at home, no exhaust, under $200.
Open-source DIY guide (60 pages, step-by-step).
🧰 HEPA + partial heat recovery
medium.com/@levangelist...
May 16, 2025 at 1:58 AM
Just published:
Build the FantaMix — fresh filtered air at home, no exhaust, under $200.
Open-source DIY guide (60 pages, step-by-step).
🧰 HEPA + partial heat recovery
medium.com/@levangelist...
Build the FantaMix — fresh filtered air at home, no exhaust, under $200.
Open-source DIY guide (60 pages, step-by-step).
🧰 HEPA + partial heat recovery
medium.com/@levangelist...
🧵1/6
I just published the first look at FantaMix, a DIY system that brings in outdoor HEPA-filtered air — and recovers a bit of heat.
It’s simple, low-cost, and works even with tricky window setups.👇
I just published the first look at FantaMix, a DIY system that brings in outdoor HEPA-filtered air — and recovers a bit of heat.
It’s simple, low-cost, and works even with tricky window setups.👇
May 13, 2025 at 10:52 PM
🧵1/6
I just published the first look at FantaMix, a DIY system that brings in outdoor HEPA-filtered air — and recovers a bit of heat.
It’s simple, low-cost, and works even with tricky window setups.👇
I just published the first look at FantaMix, a DIY system that brings in outdoor HEPA-filtered air — and recovers a bit of heat.
It’s simple, low-cost, and works even with tricky window setups.👇
A group of NZ doctors, teachers and others, have written an open letter to the Government requesting C02 monitors, air purifiers, free tests, paid leave and recognition of LongCOVID as an occupational hazard, saying too many are still getting Covid.
www.thepost.co.nz/nz-news/3606...
www.thepost.co.nz/nz-news/3606...
‘Sick of being sick’: Call to fix air quality in schools and childcare
Tamariki should not be bringing home illnesses and spreading it to their families, says a group of doctors, teachers, academics and principals.
www.thepost.co.nz
May 1, 2025 at 10:00 AM
A group of NZ doctors, teachers and others, have written an open letter to the Government requesting C02 monitors, air purifiers, free tests, paid leave and recognition of LongCOVID as an occupational hazard, saying too many are still getting Covid.
www.thepost.co.nz/nz-news/3606...
www.thepost.co.nz/nz-news/3606...
Drying my hair caused PM2.5 levels to spike from 0.1 to 109 µg/m³ in just a few minutes.
Indoor air pollution can be surprisingly high without us noticing.
You can't fix what you don't measure.
Indoor air pollution can be surprisingly high without us noticing.
You can't fix what you don't measure.
April 27, 2025 at 3:18 PM
Drying my hair caused PM2.5 levels to spike from 0.1 to 109 µg/m³ in just a few minutes.
Indoor air pollution can be surprisingly high without us noticing.
You can't fix what you don't measure.
Indoor air pollution can be surprisingly high without us noticing.
You can't fix what you don't measure.
1/3 DIY window air exchanger with HEPA — built while house-sitting for my partner during her trip down south.
Not an HRV, just a simple air exchanger — quiet, effective fix (~35 dB) for high CO₂ in a tiny bedroom, for under $100. 3–4h build & install 3-night CO₂ test 1h airflow + sound testing
Not an HRV, just a simple air exchanger — quiet, effective fix (~35 dB) for high CO₂ in a tiny bedroom, for under $100. 3–4h build & install 3-night CO₂ test 1h airflow + sound testing
April 18, 2025 at 6:33 PM
1/3 DIY window air exchanger with HEPA — built while house-sitting for my partner during her trip down south.
Not an HRV, just a simple air exchanger — quiet, effective fix (~35 dB) for high CO₂ in a tiny bedroom, for under $100. 3–4h build & install 3-night CO₂ test 1h airflow + sound testing
Not an HRV, just a simple air exchanger — quiet, effective fix (~35 dB) for high CO₂ in a tiny bedroom, for under $100. 3–4h build & install 3-night CO₂ test 1h airflow + sound testing
healthydebate.ca/2025/04/topi...
What if we told you a simple metal box could greatly improve global health?
What if we told you a simple metal box could greatly improve global health?
The simple metal box that could change the world - Healthy Debate
This quiet, repairable metal air cleaner is an inexpensive long-term disease prevention tool for public spaces.
healthydebate.ca
April 17, 2025 at 10:27 AM
healthydebate.ca/2025/04/topi...
What if we told you a simple metal box could greatly improve global health?
What if we told you a simple metal box could greatly improve global health?
1/ 4 In many living spaces, my first advice is simple:
Get an air quality monitor (CO₂, TVOCs, PM2.5, humidity).
Because as one study said: when we monitor, we start to “see” the air. That alone motivates action. www.lse.ac.uk/granthaminst...
Get an air quality monitor (CO₂, TVOCs, PM2.5, humidity).
Because as one study said: when we monitor, we start to “see” the air. That alone motivates action. www.lse.ac.uk/granthaminst...
Making the invisible visible: the impact of revealing indoor air pollution on behavior and welfare - Grantham Research Institute on climate change and the environment
This paper reports on an experiment in London that monitored households’ indoor air pollution levels and how they reacted to receiving real-time information on those levels.
www.lse.ac.uk
April 15, 2025 at 11:03 AM
1/ 4 In many living spaces, my first advice is simple:
Get an air quality monitor (CO₂, TVOCs, PM2.5, humidity).
Because as one study said: when we monitor, we start to “see” the air. That alone motivates action. www.lse.ac.uk/granthaminst...
Get an air quality monitor (CO₂, TVOCs, PM2.5, humidity).
Because as one study said: when we monitor, we start to “see” the air. That alone motivates action. www.lse.ac.uk/granthaminst...
🧪 New test published.
I reviewed the Purifresh — a compact window-mounted energy recovery ventilator (ERV).
Includes real-world data, airflow tests, noise measurements, use cases, and personal verdict.
👉 medium.com/@levangelist...
#airquality #ventilation #HRV #ERV
I reviewed the Purifresh — a compact window-mounted energy recovery ventilator (ERV).
Includes real-world data, airflow tests, noise measurements, use cases, and personal verdict.
👉 medium.com/@levangelist...
#airquality #ventilation #HRV #ERV
Purifresh Review
Surprisingly powerful for its size — a flexible window ERV for many real-world…
This article is part of the series announced in “HRVs Without Ducts for Everyone: Announcing an Upcoming Series on Testing and Reviews “
medium.com
April 14, 2025 at 12:01 AM
🧪 New test published.
I reviewed the Purifresh — a compact window-mounted energy recovery ventilator (ERV).
Includes real-world data, airflow tests, noise measurements, use cases, and personal verdict.
👉 medium.com/@levangelist...
#airquality #ventilation #HRV #ERV
I reviewed the Purifresh — a compact window-mounted energy recovery ventilator (ERV).
Includes real-world data, airflow tests, noise measurements, use cases, and personal verdict.
👉 medium.com/@levangelist...
#airquality #ventilation #HRV #ERV