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HVAC Controls tech here; Commercial buildings have all sorts of rules under Ashrae in the US. Generally in commercial there is a minimum air exchange rate for

HVAC Controls tech here; Commercial buildings have all sorts of rules under Ashrae in the US. Generally in commercial there is a minimum air exchange rate for occupied space. Pre covid it was being constricted for "green" energy initiatives in the name of energy and $$ savings. That restriction was allowed to be really clamped down on (more savings) if certain conditions were met like CO2 monitoring or people counters, both more tightly targeting how much fresh air people actually need and minimizing waste in conditioning outside air that isn't necessary. Post covid a lot of that got thrown out, commercial buildings are now generally over shooting OA exchange in the name of not turning these spaces into germ breeding grounds. None of this really exists in the residential sector, but maybe it should. Homes in even the recent past are "leaky" enough to get enough outside air exchange for the low occupancy rates without actively conditioning and bringing in outside air. Some modern energy efficient homes that are wrapped and sealed extremely well might pose an issue to this. By all means get a decent sensor that reads CO2, CO, PM1, PM2.5, and VOC. Radon if you are in a risk area. Your regular thermostat probably already gets you temp and humidity. It needs to have some way to do long term data logging, five or ten minute sample rate for a year for example. You really want to see how things are different across seasons. With that data in hand there are plenty of things you can do if you need to introduce more OA to occupied spaces. Generally there are heat exchangers that can be dedicated to that sort of thing. Or a simple motorized damper opening up a small filtered OA duct on the intake side of the air handling unit. Ideally those devices would only be activated on unacceptably high bad air quality readings.

criddell 4y ago
I was thinking about installing an air quality meter of some kind in my office because I suspect CO2 is high. Some of those other things (CO, PM1, etc...) may also be off. If I install a meter and find CO2 is high, do the Ashrae guidelines give me any leverage against the building management? Already it's often too hot because I'm on the top floor and I think they run the heat for the people on the bottom floor who are cold and the HVAC system doesn't seem to be able to deal with this.
- Maxburn 4y ago
  There are guidelines in the spec but I think they are quite high. There's also studies that high CO2 kills concentration in schools, those seem more reasonable. Zoned systems are supposed to be able to handle individual zone heating/cooling issues, floor to floor without question should be able to be controlled. Entirely depends on what is installed and how it is controlled. This is an area where cost cutting happens. Generally there's a ashrae spec saying there is a minimum of five degrees °F between heating and cooling. So sure get a couple data loggers and report any findings to your manager.
insaneirish 4y ago
> None of this really exists in the residential sector, but maybe it should. The requirements exist in the IRC [1] but are frequently not enforced in many jurisdictions. [1]: https://www.energyvanguard.com/blog/2018-building-code-makes-change-in-ventilation/ https://www.energyvanguard.com/blog/2018-building-code-makes...
- Maxburn 4y ago
  Amazing, I've never even heard of a ERU in residential work. I'm not an engineer so I'm unaware of the rules and regulations, I'm just pointing out what I've actually seen getting installed and what engineers sequences say about it.
  - insaneirish 4y ago
    That blog I linked to is great; it's written by the principal of an HVAC design firm who is well respected. Green Building Advisor (https://www.greenbuildingadvisor.com https://www.greenbuildingadvisor.com) is a great community for such things, with a 99% residential focus. I have an ERV in my house, running continuously. There are some great pieces of equipment out there, but they require conscious consumers and/or progressive code enforcement to end up in use.
Syzygies 4y ago
I was blown away years ago, visiting the Anchor brewery in San Francisco. They approximated traditional steam beer in an enormous shallow pool. To improve consistency the whole room was at positive pressure, using state-of-the-art hospital air filtering. Aside from the smell of beer, it was like stepping out into the Swiss Alps. I've never understood why rich people will spend $40K on audiophile equipment yet put up with crappy phones; I did a BBC interview remote in their NY studio using a $10K mic and the difference was staggering. Here, I swore if I ever got rich I'd want good indoor air. It turns out I can afford to redo my house in California with a heat exchanger. I'm certain the hardest part will be finding a contractor who will exceed standards. Standards are why I have 1/2" pipes under my house. I want the bleeding edge of what's possible in my lifetime.
- altairprime 4y ago
  I was able to positive pressurize my apartment with an IQair during the ‘17-20 wildfires; it’s really worth it if you can figure out the intricacies and get it done.
  - Maxburn 4y ago
    Every single building is supposed to be positive with conditioned air at all times. Any building that's negative pulls in unconditioned air through all the cracks. Where I live it's very humid (think Houston TX) and if you pull that air in for a long time you end up with black mold inside the walls.
    - altairprime 4y ago
      Must be nice. My building's only "intake" was in my hallway ceiling, pulling in air from the farthest point from all windows.
      - Maxburn 4y ago
        Might be by design. Plenty of buildings have a dedicated OA unit dumping into common areas and it gets pushed out to the private areas and individual rooms. Then gets pulled out via exhaust fans in rest rooms and other places.
jnxx 4y ago
> Post covid a lot of that got thrown out, commercial buildings are now generally over shooting OA exchange in the name of not turning these spaces into germ breeding grounds. I think it has become clear that germ loads can be reduced significantly with filtering and ventilation.
samuraixp 4y ago
I have been getting pretty high VOC readings in my bedroom on a uHoo, Airthings and now even the Dyson HP09 shows some lower levels. So now I am confident there is something being detected. Any advice on how to debug what is causing it and what VOCs it might actually be? The weird thing is it seems to mostly spike at night time and even more so on the weekends. I have a few hypothesis, such as: - furniture offgassing - us being in the bedroom - gas cooking in the apartment building somehow settling into our ground floor apartment at night? - it seems to be worse if we have the aircon on - it really only seems to properly dissapate when the windows are open and theres good breeze and there seems to be a correlation between that and the sun coming up?
- Maxburn 4y ago
  VOC? Deodorant, hairspray, perfume, cologne, scented soap, fabric softener. My VOC in the office spikes when I first get in from a couple of those items.
- walterbell 4y ago
  > Any advice on how to debug what is causing it Like bisecting code, you can bisect airflow with plastic (e.g. 6 mil polyethylene) sheeting. Move the VOC sensor between isolated zones, or use multiple VOC sensor logs to track dispersal time/direction, narrowing down potential sources. > it seems to be worse if we have the aircon on Central or window aircon? You could place a VOC sensor near the HVAC duct input.

criddell 4y ago

I was thinking about installing an air quality meter of some kind in my office because I suspect CO2 is high. Some of those other things (CO, PM1, etc...) may also be off. If I install a meter and find CO2 is high, do the Ashrae guidelines give me any leverage against the building management? Already it's often too hot because I'm on the top floor and I think they run the heat for the people on the bottom floor who are cold and the HVAC system doesn't seem to be able to deal with this.

Maxburn 4y ago
There are guidelines in the spec but I think they are quite high. There's also studies that high CO2 kills concentration in schools, those seem more reasonable. Zoned systems are supposed to be able to handle individual zone heating/cooling issues, floor to floor without question should be able to be controlled. Entirely depends on what is installed and how it is controlled. This is an area where cost cutting happens. Generally there's a ashrae spec saying there is a minimum of five degrees °F between heating and cooling. So sure get a couple data loggers and report any findings to your manager.

insaneirish 4y ago

> None of this really exists in the residential sector, but maybe it should. The requirements exist in the IRC [1] but are frequently not enforced in many jurisdictions. [1]: https://www.energyvanguard.com/blog/2018-building-code-makes-change-in-ventilation/ https://www.energyvanguard.com/blog/2018-building-code-makes...

Maxburn 4y ago
Amazing, I've never even heard of a ERU in residential work. I'm not an engineer so I'm unaware of the rules and regulations, I'm just pointing out what I've actually seen getting installed and what engineers sequences say about it.
- insaneirish 4y ago
  That blog I linked to is great; it's written by the principal of an HVAC design firm who is well respected. Green Building Advisor (https://www.greenbuildingadvisor.com https://www.greenbuildingadvisor.com) is a great community for such things, with a 99% residential focus. I have an ERV in my house, running continuously. There are some great pieces of equipment out there, but they require conscious consumers and/or progressive code enforcement to end up in use.

Syzygies 4y ago

I was blown away years ago, visiting the Anchor brewery in San Francisco. They approximated traditional steam beer in an enormous shallow pool. To improve consistency the whole room was at positive pressure, using state-of-the-art hospital air filtering. Aside from the smell of beer, it was like stepping out into the Swiss Alps. I've never understood why rich people will spend $40K on audiophile equipment yet put up with crappy phones; I did a BBC interview remote in their NY studio using a $10K mic and the difference was staggering. Here, I swore if I ever got rich I'd want good indoor air. It turns out I can afford to redo my house in California with a heat exchanger. I'm certain the hardest part will be finding a contractor who will exceed standards. Standards are why I have 1/2" pipes under my house. I want the bleeding edge of what's possible in my lifetime.

altairprime 4y ago
I was able to positive pressurize my apartment with an IQair during the ‘17-20 wildfires; it’s really worth it if you can figure out the intricacies and get it done.
- Maxburn 4y ago
  Every single building is supposed to be positive with conditioned air at all times. Any building that's negative pulls in unconditioned air through all the cracks. Where I live it's very humid (think Houston TX) and if you pull that air in for a long time you end up with black mold inside the walls.
  - altairprime 4y ago
    Must be nice. My building's only "intake" was in my hallway ceiling, pulling in air from the farthest point from all windows.
    - Maxburn 4y ago
      Might be by design. Plenty of buildings have a dedicated OA unit dumping into common areas and it gets pushed out to the private areas and individual rooms. Then gets pulled out via exhaust fans in rest rooms and other places.

jnxx 4y ago

> Post covid a lot of that got thrown out, commercial buildings are now generally over shooting OA exchange in the name of not turning these spaces into germ breeding grounds. I think it has become clear that germ loads can be reduced significantly with filtering and ventilation.

samuraixp 4y ago

I have been getting pretty high VOC readings in my bedroom on a uHoo, Airthings and now even the Dyson HP09 shows some lower levels. So now I am confident there is something being detected. Any advice on how to debug what is causing it and what VOCs it might actually be? The weird thing is it seems to mostly spike at night time and even more so on the weekends. I have a few hypothesis, such as: - furniture offgassing - us being in the bedroom - gas cooking in the apartment building somehow settling into our ground floor apartment at night? - it seems to be worse if we have the aircon on - it really only seems to properly dissapate when the windows are open and theres good breeze and there seems to be a correlation between that and the sun coming up?

Maxburn 4y ago
VOC? Deodorant, hairspray, perfume, cologne, scented soap, fabric softener. My VOC in the office spikes when I first get in from a couple of those items.
walterbell 4y ago
> Any advice on how to debug what is causing it Like bisecting code, you can bisect airflow with plastic (e.g. 6 mil polyethylene) sheeting. Move the VOC sensor between isolated zones, or use multiple VOC sensor logs to track dispersal time/direction, narrowing down potential sources. > it seems to be worse if we have the aircon on Central or window aircon? You could place a VOC sensor near the HVAC duct input.