All the tech in the world won't change anything if people don't focus on airflow and airchanges. Air needs to move and be replenished with air from the outside. Filters/UV/etc are just a bonus.

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_carbyau_ a day ago | parent | next [-]

> if people don't focus on airflow and airchanges

Even basic airflow understanding is surprisingly not common knowledge. IE for air to leave a room occupied by humans, then air needs a path into that room too.

I commonly see ceiling exhaust fans in bathroom showers and toilets with windows sealed shut. The door is meant to be closed... so the only gap for air to come into the room is around the door somehow - while the exhaust fan struggles.

I even visited one host who implemented a seal along the bottom of the door because:

1. Shower creates steam and with the above mentioned little airflow, that steam stayed around.

2. So the exhaust fan had to run while they dried themselves with a towel.

3. But they didn't like getting cold feet from the draft of air coming in under the door...

I could not convince them they needed an air intake vent. :-(

Similar but different, a couple of times now I've been in hotel rooms with a bar fridge buzzing away entirely enclosed in a cupboard. Extrapolate that to the hundred rooms or more of the hotel and it is a colossal waste thanks to a "simple" understanding of airflow.

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Aurornis a day ago | parent [-]

> I commonly see ceiling exhaust fans in bathroom showers and toilets with windows sealed shut. The door is meant to be closed... so the only gap for air to come into the room is around the door somehow

If the building has central air heating or cooling, having a vent into the bathroom is standard. That’s more than enough for the exhaust fan to pull from.

In areas where central air is uncommon, you need a decent door undercut. A surprising amount of air can flow around a door and modern exhaust fans can pull a relatively good vacuum.

	▲	schiffern a day ago \| parent [-]
		Yeah, the real pro tip here is sealing the bottom of your bathroom door to avoid cold feet. Genius!

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derefr a day ago | parent | prev | next [-]

> be replenished with air from the outside

I live in an apartment above a busy road, and my building has no central HVAC. Opening my windows makes the air (much, much) worse.

It took a while to figure this out, so from the ~1.5 years I've lived here, I've accumulated huge, thick coats of brake dust on my windowsills, in my carpets, on the blades of my air-circulation floor... and so on. Probably am half-way to developing COPD.

I do still "replenish air from outside", though! ...through a three-stage filter. (I put an industrial air scrubber on my balcony, and fed the exhaust from it inside through the same kind of doorjam seal you'd use for a portable AC unit.)

I still get noxious fumes coming in sometimes, though. I had to set the thing up on a timer so it wouldn't pull air in during rush hour.

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ortusdux a day ago | parent | prev | next [-]

I've been running an airgradient sensor for a year now and as a result I am seriously considering adding a MERV to my HVAC system. Ideally I'd like to get two more sensors (one outside, one in the HVAC ducts) and setup home assistant to govern air exchanges.

	▲	schiffern a day ago \| parent \| next [-]
		Tip: avoid the cheap 1" filters that only have a few pleats. Fewer pleats = less surface area = more flow resistance. Many HVAC people will recommend thicker filters (3-6" thick) if using a higher MERV, but the 1" 3M 1900 often has more actual surface area if laid flat. Testing by Project Farm and others showed the 3M 1900 filter has the lowest airflow resistance of any 1" high-MERV filter. If your HVAC only accepts a 1" filter, that's the only brand I'd use. Change the filter ideally every 3 months, but to avoid costly HVAC repairs don't exceed 6 months maximum.
	▲	turtlebits 14 hours ago \| parent \| prev [-]
		You can damage/destroy your furnace if you put in a too restrictive filter. Better to follow manufacturer recommendations and add circulating air filters in your house.

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throw0101c a day ago | parent | prev | next [-]

> * Air needs to move and be replenished with air from the outside. Filters/UV/etc are just a bonus.*

Outside air needs to be filtered otherwise you can bring in pollen and other things (e.g., exhaust/brake dust from cars if near heavy arteries). Avoid UV for residences:

* https://www.youtube.com/watch?v=xLwHmfdwO9s

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lazide a day ago | parent [-]

Or for anyone on the west coast the last 5 years, nasty smoke.

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throw0101c a day ago | parent | next [-]

Carbon filters on your incoming air supply (e.g., ERV):

* https://shop.aprilaire.com/search?q=Carbon+Air+Filter

	▲	lazide 20 hours ago \| parent [-]
		1) broken link 2) any (actual) HEPA filter works too. A lot of stuff sold as HEPA doesn’t meet the original HEPA standards though, so needs to be actually rated for the super small particles.

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wahnfrieden a day ago | parent | prev [-]

Toronto also

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jerlam a day ago | parent | prev | next [-]

Yes, there is a whole certification system for measuring how well an air purifier works (CADR - Clean Air Delivery Rate) but consumers are easily distracted and confused by flashy features that promise everything but usually don't do much.

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quickthrowman a day ago | parent | prev [-]

If by ‘people’ you mean ‘mechanical engineers’, they already do, see ASHRAE 62.1 - Ventilation and Acceptable Indoor Air Quality

https://static1.squarespace.com/static/6320b844c3820725e4d56...