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Ask HN: Best way to remove CO2 in a bedroom?

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Re: Ask HN: Best way to remove CO2 in a bedroom?

#91

Post by OutOfHere »

Llamamoe wrote: post #88
OutOfHere wrote: post #72

Earlier quoted context omitted.

Thanks for the math. The parent comment has been slightly edited. I'd ideally want the CO2 to be the preindustrial level of under 300 ppm. The reason is that I suspect it could lead to maximum alertness and a feeling of well-being. Note that some ventilation still is needed during the day to get O2 and remove VOCs, so the calculations are affected. In your calculation, remember to account for the presence of people w…

The amount of O2 removed from the air is negligible compared to the impact of elevated CO2 on human gas exchange tbh. I doubt you'd have much benefit going down to 300 instead of 400, and it introduces a whole other problem - aiming at sub-ambient CO2 targets makes ventilation increase the amount of scrubbing you need to do instead of decreasing it. I imagine the increase in cost would be massive. But yeah it'd proba…

Thinking ahead, as the atmospheric outdoor level keeps climbing, ventilation will become insufficient to achieve a desired target indoor level. Air conditioning suffers from the extreme version of the same problem. Yes, the cost is substantial if using Soda Lime.

Amines are traditionally used instead in a closed loop system, but they are corrosive and unsafe for use at home, although refrigerators and ACs too make use of similar loops. GPT says that some non-corrosive common amino acid salts can be used instead, but I find it difficult to believe.

Re: Ask HN: Best way to remove CO2 in a bedroom?

#92

Post by hagbard_c »

slau wrote: post #56
therobots927 wrote: post #40

Earlier quoted context omitted.

Also if you live in an area with low humidity look into getting a swamp cooler. It won’t make the air as cold as AC but I personally prefer it

Swamp coolers can get really nasty and smelly due to being the perfect breeding ground for spores and other nasties.

I suspect a UV lamp over the evaporator would solve this problem. It would not need to be lit continuously, just at a regular interval short enough to quash any fledgeling fungal or bacterial growth. There may be swamp coolers which have such a sterilising function integrated, otherwise it'd be a useful hack with market potential.

Re: Ask HN: Best way to remove CO2 in a bedroom?

#93

Post by colanderman »

l1tany11 wrote: post #90
colanderman wrote: post #30

Energy recovery ventilator. It will exchange indoor air with outdoor air while maintaining indoor heat and humidity. Unfortunately small window mounted models are hard to come by. Most are whole-home systems.

Panasonic ones go down to 50cfm, which is fine for a bedroom. That being said, everything in construction comes down to “it depends” because there is so much variability including just in execution. In California for instance there are mechanical whole home ventilation requirements, but those requirements are quite low and are commonly ineffective for the OPs goal depending on how the system is arranged. Same thing g…

Agree with all these suggestions. Except I would caution against simply having a fan that sucks air out of the bedroom without also having a low-resistance path for air to enter the bedroom. If there's no easy way for air to get in, it will get sucked up through the walls and floors taking odors and mold spores with it.

Re: Ask HN: Best way to remove CO2 in a bedroom?

#96

Post by colanderman »

dzhiurgis wrote: post #86
colanderman wrote: post #30

Energy recovery ventilator. It will exchange indoor air with outdoor air while maintaining indoor heat and humidity. Unfortunately small window mounted models are hard to come by. Most are whole-home systems.

Whole home ones are only real ones having a chance to work. I’ve installed mine in about 6hours (but I do have moderately accessible attic). They are somewhat cheap too - at $1k or so.

I used to have a window mounted unit from a small company. It worked wonderfully in my bedroom.

Re: Ask HN: Best way to remove CO2 in a bedroom?

#97

Post by therobots927 »

hagbard_c wrote: post #92
slau wrote: post #56

Earlier quoted context omitted.

Swamp coolers can get really nasty and smelly due to being the perfect breeding ground for spores and other nasties.

I suspect a UV lamp over the evaporator would solve this problem. It would not need to be lit continuously, just at a regular interval short enough to quash any fledgeling fungal or bacterial growth. There may be swamp coolers which have such a sterilising function integrated, otherwise it'd be a useful hack with market potential.

Yeah that’s not a bad idea. And often swamp coolers have electric sockets inside so it wouldn’t be too hard to wire it out. If I wasn’t renting the place I’d probably give it a shot

Re: Ask HN: Best way to remove CO2 in a bedroom?

#98

Post by tgv »

spiffytech wrote: post #55
tgv wrote: post #16

Breathing during sleep adds only little CO2 to the environment. Here's a calculator: https://www.omnicalculator.com/ecology/co2-breathing-emissio... .

My CO2 sensor shows up to 2,600 ppm overnight if we don't actively vent our bedroom. 500-750 if we do, depending on which in-window fan model and how high we set it.

That's that's quite a lot more than expected. Isn't there another source of CO2?

Re: Ask HN: Best way to remove CO2 in a bedroom?

#99

Post by GeoAtreides »

tgv wrote: post #98
spiffytech wrote: post #55

Earlier quoted context omitted.

My CO2 sensor shows up to 2,600 ppm overnight if we don't actively vent our bedroom. 500-750 if we do, depending on which in-window fan model and how high we set it.

That's that's quite a lot more than expected. Isn't there another source of CO2?

I have two true CO2 sensors in my room (SCD30, SCD41), and I can confirm the CO2 concentration rises to 2400-2900 ppm during the night. But it's very easy to vent, a draft will reset the concentration to background levels in a minute or so.

Re: Ask HN: Best way to remove CO2 in a bedroom?

#100

Post by fartfeatures »

timrichard wrote: post #85
fartfeatures wrote: post #35

Earlier quoted context omitted.

In the UK, trickle vents above windows and doors were historically used for passive ventilation to prevent mould by allowing airflow. However, modern building practices and regulations, including stringent air tightness requirements mandated by Building Control, have shifted focus towards more efficient ventilation solutions like Mechanical Ventilation with Heat Recovery (MVHR) systems. While trickle vents are still…

We're in the process of getting windows replaced, and the window company said they are now mandatory on all new and replacement windows. Apparently, it became law in June 2022.

Yes in retrofit, OP was suggesting that they are mandatory in new build houses and that is not the case. If they were mandatory nobody would be fitting MVHRs as trickle vents make them not function.
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