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The bottleneck might be the air in the room

blog.mikebowler.ca

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Re: The bottleneck might be the air in the room

#321

Post by throw0101a »

cucumber3732842 wrote: post #247
throw0101a wrote: post #229

Earlier quoted context omitted.

> The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are. The point of having "tight" houses is not (just) about energy efficiency but about air quality as well. The general mantra is build tight, ventilate right . It's why modern building codes mandate air tightness and having ER…

Not everywhere is LA. How much does implementing all that cost? What degree of benefit does it offer over simple window in situations where those concerns are negligible? What other benefits to human life could be procured with that money? It just boggles the mind that people feel emboldened to only look at one side of the equation.

> Not everywhere is LA.

> How much does implementing all that cost? What degree of benefit does it offer over simple window in situations where those concerns are negligible? What other benefits to human life could be procured with that money?

Everywhere not being LA is actually an argument for ERVs/HRVs. The weather in LA (AIUI) is fairly even and consistent and it is probably fairly easy to just open a window.

But if you're in Texas with high humidity, or Arizona with high heat, or north of the Mason-Dixon line where people get winter, it's kind of hard to open a window when it's 0 or -10 outside. If you have stale air (perhaps as measured by high CO2) what are you supposed to do?

Over the July 4, 2026, weekend it's supposed to get >90F/>32C on the east coast of the US: do you want to open your windows and let all of that heat in? Especially if you already have an AC unit so paid to run it get your home's inside temperature down?

If you have a place with ducts, you can purchase an ERV and tap into that for US$ 1000:

* https://www.hvacquick.com/products/residential/HRVs-and-ERVs...

or even less:

* https://hvacdirect.com/air-cleaning/erv-air-exchangers.html

And even in milder climates (like LA), have the ERV suck in air from the outside through an MERV 13(+) carbon filter, and not only do you deal with things like wild fire smoke, but wild fire smell:

* https://www.greenbuildermedia.com/blog/wildfires-make-indoor...

* https://shop.aprilaire.com/products/aprilaire-513cbn-odor-re...

It is possible to make your indoor air cleaner than the air outside.

Re: The bottleneck might be the air in the room

#322

Post by amluto »

mort96 wrote: post #275
throw0101a wrote: post #229

Earlier quoted context omitted.

> The good news is that I stopped worrying about making my house "tight" for the sake of energy efficiency. I keep some windows cracked all year and don't worry about how tight the door seals are. The point of having "tight" houses is not (just) about energy efficiency but about air quality as well. The general mantra is build tight, ventilate right . It's why modern building codes mandate air tightness and having ER…

I would not want to live in a city where I have to be careful letting in outside air or going outside because there's too much air pollution...

Even if you live in an air quality paradise, it’s not ideal for your indoor air to be the air that manages to sneak through all the little cracks in your structure. Especially if you have cold outdoor temperatures, indoor humidity such that the outdoor temperatures are below the indoor dew point, and airflow through the walls that can lead to condensation and possibly mold in those walls.

Your indoor air should enter through windows or intentional intakes, not incidental gaps.

Re: The bottleneck might be the air in the room

#323

Post by throw0101a »

wouldbecouldbe wrote: post #254
throw0101a wrote: post #217

Earlier quoted context omitted.

> There are so many rooms, classrooms, movie theaters and other places with poor ventilation where you just feel dizzy, or fall asleep, not knowing it was just due to lower oxygen levels in your blood. Raising awareness is the only real solution. Not wrong, but it is perhaps worth noting that there are already standards for proper ventilation. Generally you're looking at 5–10 cfm/person (2.5-5 L/s), depending on the…

I think modern domestic houses its the opposite. At least in Netherlands insulation is such a strong focus, due to climate change I think, that modern appartments have terrible ventilation

> I think modern domestic houses its the opposite. At least in Netherlands insulation is such a strong focus, due to climate change I think, that modern appartments have terrible ventilation

The link I pointed to is all about ventilation, so just because people ignored an important component of building science, and focused on one aspect, does not invalidate it.

And while climate change is important and using efficiency to deal with it is useful, the thermal control layer is actually the least important of the four:

* https://buildingscience.com/documents/insights/bsi-001-the-p...

'Bulk' water (precipitation) and moisture can cause deterioration of the building materials (rot, crumbling), and also mold, which has its own health effects. Leaky houses can often blow conditioned air at much faster rates than thermal leakage.

Re: The bottleneck might be the air in the room

#324

Post by throw0101a »

HPsquared wrote: post #285
wouldbecouldbe wrote: post #254

Earlier quoted context omitted.

I think modern domestic houses its the opposite. At least in Netherlands insulation is such a strong focus, due to climate change I think, that modern appartments have terrible ventilation

Heat recovery ventilation is the answer to this. You also get the benefit of being able to filter it.

Energy recovery ventilation is the answer to this.

HRVs only deal with temperature, but then you have humidity that is non-controlled: moisture coming in during the summer, and getting vented out in the winter (too-dry air coming in).

ERVs handle both.

Re: The bottleneck might be the air in the room

#325

Post by amluto »

Tossrock wrote: post #12

Submarines operate in the 1000s of PPM CO2 range and the sailors aboard generally do not experience any ill effects. This was tested and no deficits were found even at 15,000 PPM: https://asma.kglmeridian.com/view/journals/amhp/89/6/article...

A major confounding factor is everything else in the air. Humans produce lots of different gases, and CO2 is usually a proxy for the overall concentration of our effluent gases. But in a submarine, or in some buildings, there are gas filters (usually carbon, possibly with various modifications) that can remove or destroy some of these gases but have no effect on CO2. So the air in a submarine at 15000ppm CO2 could be very different from the air in a an unventilated room that reaches 15000ppm CO2.

Re: The bottleneck might be the air in the room

#326

Post by freefaler »

yoshuaw wrote: post #118
Liftyee wrote: post #47

Earlier quoted context omitted.

I would hesitate to say the IKEA is worse. Inside the IKEA is a reputable Sensirion all in one sensor module. It's much cheaper and smaller because the CO2 sensor in it is using different (newer) technology that only released a few years ago from Sensirion. (Upd: the IKEA does have lower accuracy, with ±100 ppm instead of ±30 ppm. From the SEN63C datasheet)

Worse specs? Sure. Worse value? I don't think so. Worse accuracy? Perhaps not either. A price of 30 EUR makes this sensor really easy to pick up. For the same price as one Aranet (~180 EUR) the typical household can place a sensor in every room of the house. Which provides far more accurate readings for the whole house than just one high-end sensor in one room.

I have one IKEA Apstuga on my desk, sitting right next to a good CO2 monitor. Since Apstuga uses worse approach (heat) rather than light as the good sensors, it diviates around +/- 100 ppm. For example the correct CO2 is 610 ppm and IKEA's sensor shows 552 ppm with is reasonably close. So the trend will be correct and the values will not be.

But when it goes over the safe limit it should be enough to decide to ventilate.

Re: The bottleneck might be the air in the room

#327

Post by throw0101a »

amluto wrote: post #322
mort96 wrote: post #275

Earlier quoted context omitted.

I would not want to live in a city where I have to be careful letting in outside air or going outside because there's too much air pollution...

Even if you live in an air quality paradise, it’s not ideal for your indoor air to be the air that manages to sneak through all the little cracks in your structure. Especially if you have cold outdoor temperatures, indoor humidity such that the outdoor temperatures are below the indoor dew point, and airflow through the walls that can lead to condensation and possibly mold in those walls. Your indoor air should enter…

> Even if you live in an air quality paradise, it’s not ideal for your indoor air to be the air that manages to sneak through all the little cracks in your structure.

Small cracks are also things that critters may be able to get through.

Re: The bottleneck might be the air in the room

#328

Post by dml2135 »

joezydeco wrote: post #319
dgellow wrote: post #179

Earlier quoted context omitted.

Worst case people open windows without effect, no?

Opening windows can bring in pollen, dust, humidity, noise, and a lot of energy loss during cold winters and hot summers. In a bedroom it might be worse than the elevated CO2 problem.

That’s a bit of a dramatic way to describe opening a window.

Re: The bottleneck might be the air in the room

#329

Post by misnome »

gpt5 wrote: post #6

I really wish a Apple or another major OEM would integrate CO2 monitor into watches or smartphones. Suddenly, everybody would be aware of the CO2 level in the room, get alerts, etc. and the problem will just solve itself. There are so many rooms, classrooms, movie theaters and other places with poor ventilation where you just feel dizzy, or fall asleep, not knowing it was just due to lower oxygen levels in your blood…

I built a conference badge with a proper, laser-based CO2 sensor.

It didn't work very well because just by virtue of being near me all the time, it didn't get a very good measure of the average room contents.

Re: The bottleneck might be the air in the room

#330

Post by joezydeco »

dml2135 wrote: post #328
joezydeco wrote: post #319

Earlier quoted context omitted.

Opening windows can bring in pollen, dust, humidity, noise, and a lot of energy loss during cold winters and hot summers. In a bedroom it might be worse than the elevated CO2 problem.

That’s a bit of a dramatic way to describe opening a window.

I've been designing my own ERV system for the house and have been weighing all the options, so I had this list in my head. Nothing dramatic, just the reality. We have allergies and like sleeping in a cooler bedroom.
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