High carbon dioxide in the home

[cbo111]

I live in a concrete block home in Florida that was built in 2015. I recently acquired a CO2 meter and found the level is consistently around 1150 ppm in most of the rooms. With the oppressive summer heat and humidity, we keep the windows closed and the AC running all the time. Doing a little research, I learned that very little outside air is used to keep the house cool. The AC system just cools and circulates the same indoor air, which is economically efficient, but perhaps not so healthy. Today at a family gathering in my home, five additional people (7 total in the home), raised the level to over 1700 ppm. These levels are not considered dangerous, but numerous studies have found levels over 1000 ppm to present symptoms like fatigue, dizziness, headache, etc. No wonder I always feel like crap when my family comes to visit! But seriously, anybody know how to reduce CO2 in the home during summer heat when opening windows is not an option? And don't say plants. We have about 50 plants in our home.

 

[badatmath]

Well you could probably open the windows for 15 minutes or something. It isn't anything I'd be worried about.

 

[Jerry1]

Homes that are really tight should have an air exchanger. They exchange the air by conditioning it (heat or cool) using the inside air.

 

[RetiredHappy]

Wouldn't the new HVAC systems have a built-in air exchanger already?

 

[NgineER]

Homes that are really tight should have an air exchanger. They exchange the air by conditioning it (heat or cool) using the inside air.

+1-should look at an HRV for the home. This is separate from your HVAC system.

 

[FlaGator]

Nice to have a tightly sealed house in Florida, eh? Comes in handy on windy/stormy/hurricane days, and I'm glad for my 2015 model house.

I've haven't checked those levels, doubt I ever will now that it's just me in 2000+ sq ft.

Since the once-Beautiful Princess left, I no longer have to worry about anyone's allergies, so I open the doors for a while in the morning as long as the ambient is below 80. Figure the AC will dry it out over the next few hours.

 

[Spock]

Just for giggles... put a bunch of live plants in a room and close the door and vents. Wait a couple of days and see if that room reads different.

Concrete putting off CO2 is what messed up the original Biosphere2 experiment in AZ. But noting I would worry about.
Up here the "concern" is radon.

 

[eytonxav]

Our house was built in 2013 and came with a Honeywell air exchanger controlled vent as shown in the video. I can attest to what the guy is saying about not running it in very cold or hot weather, but it should help alleviate C02 buildup during more moderate temperatures.

 

[latexman]

Add some plants inside?

 

[pacergal]

No matter what the weather, we always have one window cracked about 1/4 inch for fresh air year round. It's in the back part of the house, in a bathroom, so doesn't really affect the thermostat for heat or AC.
But we do not live in a very humid area.
We also have two CO2 monitor/alarms in the house.

 

[Aerides]

But seriously, anybody know how to reduce CO2 in the home during summer heat when opening windows is not an option? And don't say plants. We have about 50 plants in our home.

S. Fla here. I am in and out often enough with the cats and gardening that the patio doors in the middle of our house get opened plenty.

My parents are also in the area, and they always - yes even in July - open a few windows every morning when they first get up, for a maybe 5-10 minutes to help avoid any issues and get "fresh" air in.

 

[OldShooter]

... I recently acquired a CO2 meter and found the level is consistently around 1150 ppm in most of the rooms. ... today at a family gathering in my home, five additional people (7 total in the home), raised the level to over 1700 ppm. These levels are not considered dangerous, but numerous studies have found levels over 1000 ppm to present symptoms like fatigue, dizziness, headache, etc. No wonder I always feel like crap when my family comes to visit! ...

Correlation is not causality. I suggest you attempt to validate both your meter accuracy and your diagnosis before spending a lot of money.

The pollution agencies love sounding alarms based on the presence of trace amounts of whatever chemical makes the mice unhappy when they are exposed to high concentrations. Sure, CO2 is dangerous in high concentrations. So is water.

 

[Dash man]

No matter what the weather, we always have one window cracked about 1/4 inch for fresh air year round. It's in the back part of the house, in a bathroom, so doesn't really affect the thermostat for heat or AC.
But we do not live in a very humid area.
We also have two CO2 monitor/alarms in the house.

I suspect your alarms are actually Carbon Monoxide (CO) alarms. Much more dangerous than CO2.

 

[RetMD21]

I live in a concrete block home in Florida that was built in 2015. I recently acquired a CO2 meter and found the level is consistently around 1150 ppm in most of the rooms. With the oppressive summer heat and humidity, we keep the windows closed and the AC running all the time. Doing a little research, I learned that very little outside air is used to keep the house cool. The AC system just cools and circulates the same indoor air, which is economically efficient, but perhaps not so healthy. Today at a family gathering in my home, five additional people (7 total in the home), raised the level to over 1700 ppm. These levels are not considered dangerous, but numerous studies have found levels over 1000 ppm to present symptoms like fatigue, dizziness, headache, etc. No wonder I always feel like crap when my family comes to visit! But seriously, anybody know how to reduce CO2 in the home during summer heat when opening windows is not an option? And don't say plants. We have about 50 plants in our home.

I have a C02 meter and the same problem: what do you do with the results. When it's just 2 of us we have enough cubic feet and leaks to stay under 1000 but it rises overnight in the bedroom if we have the door closed. I don't think the cost/benefit is favorable for an air exchanger for us. I did decide not to try to seal more air leaks.

 

[ERD50]

I suspect your alarms are actually Carbon Monoxide (CO) alarms. Much more dangerous than CO2.

That's what I was thinking, never heard of checking CO2 levels. But, CO levels are dangerous at just 150 ppm

At sustained CO concentrations above 150 to 200 ppm, disorientation, unconsciousness, and death are possible.

, so i guess it is CO2.

Well, with my beer brewing, carbonating, and then pouring/drinking, I would imagine y levels could be pretty high! But we keep the windows open as much as weather permits (not much in winter).

So readings of 1,000 must be CO2, or I doubt the OP could be typing this! But I don't think those levels require any action. From OSHA (which I think is generally conservative?):

What are the symptoms of different levels of exposure?

5,000 ppm (0.5%) OSHA Permissible Exposure Limit (PEL) and ACGIH Threshold Limit
Value (TLV) for 8-hour exposure

10,000 ppm (1.0%) Typically no effects, possible drowsiness

-ERD50

 

[Gumby]

S. Fla here. I am in and out often enough with the cats and gardening that the patio doors in the middle of our house get opened plenty.

My parents are also in the area, and they always - yes even in July - open a few windows every morning when they first get up, for a maybe 5-10 minutes to help avoid any issues and get "fresh" air in.

In the summer, we open the windows every night before we go to sleep and close them and lower the shades when we get up. Free cooling overnight. If it's really hot, we run the window A/C unit in the bedroom to sleep and turn it off when we get up. If it is hot during the day we keep the windows closed and run a second window A/C unit that cools the office and the kitchen. I have no CO2 meter, but I'm sure our normal practices keep the concentration at ambient levels. We also have an ancient, leaky house, so that also helps.

 

[RetiredHappy]

We keep our doors and windows closed all year around and we are never worried about CO2 level. We go out every day and there is enough air exchange when we leave and return.

 

[Route246]

+1 for the air exchanger. You won't suffocate or anything like that but feeling sleepy, clueless or lethargy is a telltale sign that an O2 deficiency may be an issue.

Homes that are really tight should have an air exchanger. They exchange the air by conditioning it (heat or cool) using the inside air.

 

[cbo111]

+1 for the air exchanger. You won't suffocate or anything like that but feeling sleepy, clueless or lethargy is a telltale sign that an O2 deficiency may be an issue.

OP here,
I will plan to open some windows for a bit each morning and see if that makes a measurable difference. If not, an air exchanger might be the next option. Got to blow that dough on something.
Thanks everyone for your insights.

 

[Koolau]

That's what I was thinking, never heard of checking CO2 levels. But, CO levels are dangerous at just 150 ppm , so i guess it is CO2.

Well, with my beer brewing, carbonating, and then pouring/drinking, I would imagine y levels could be pretty high! But we keep the windows open as much as weather permits (not much in winter).

So readings of 1,000 must be CO2, or I doubt the OP could be typing this! But I don't think those levels require any action. From OSHA (which I think is generally conservative?):



-ERD50

Yeah, this is what I recalled from my days taking samples of such things. Even 1700ppm of CO2 would be unlikely to be noticeable.



IIRC Apollo 13 got up to 6% (60,000ppm.) I'm sure that level would begin to degrade performance. TLVs (Threshold Limit Value) are generally set low enough that there is a large margin of safety built in. So 0.5% (5000 ppm would be very unlikely to cause issues IMHO.)



If interested, NIOSH published a document (easily 100+ pages called "Criteria Document" IIRC) on each TLV they set. It has tons of data on why they set the level as they did. Not sure where to get these on line (I still have a library of them myself - but no CO2)


This NIOSH paper shows at least some of the documentation that may have gone into the 5000ppm limit. https://www.cdc.gov/niosh/pel88/124-38.html

 

[Gumby]

When I was a young fellow, I was a Navy submarine officer, and one of my duties was to head the division whose job included maintaining the CO2 scrubbers and associated atmosphere control equipment. As you might imagine, in a closed environment the CO2 concentration was an important number. Back then, normal atmospheric CO2 concentration was a little over 300ppm (today it is over 400ppm). But in our submarine, even if the scrubbers were working properly, it was 2000ppm or higher. My anecdotal observation is that the high CO2 levels gave me massive headaches. So, every night, when I had the midwatch as officer off the deck (midnight to 6am), I would take the boat to periscope depth, raise the snorkel mast and ventilate the boat (and do a lot of other stuff you could only do at periscope depth).

P.S. - the CO2 scrubbers used a chemical called monoethanolamine to remove CO2. It smells like dead fish and the smell permeates the boat.

 

[ERD50]

.... But in our submarine, even if the scrubbers were working properly, it was 2000ppm or higher. My anecdotal observation is that the high CO2 levels gave me massive headaches. ...

I'm curious what kind of levels affected you - something much higher than the 2000 ppm (when the scrubbers weren't working properly?)? Curious, since that OSHA guideline was for 5000 ppm over a mere 8 hours, and 10,000 maybe causing issues for some people? Of course, some people may be more sensitive - not questioning your personal experience, just trying to clarify the levels you're talking about.

.... P.S. - the CO2 scrubbers used a chemical called monoethanolamine to remove CO2. It smells like dead fish and the smell permeates the boat.

Mmmmm! Not that I needed any convincing, but that's another reason I'd never make it on a sub!

-ERD50

 

[Gumby]

I'm curious what kind of levels affected you - something much higher than the 2000 ppm (when the scrubbers weren't working properly?)? Curious, since that OSHA guideline was for 5000 ppm over a mere 8 hours, and 10,000 maybe causing issues for some people? Of course, some people may be more sensitive - not questioning your personal experience, just trying to clarify the levels you're talking about.

I cannot recall specifically what the CO2 levels were, but they were relatively high. What I do recall is that I suffered from terrible headaches when we were submerged and that they were alleviated by ventilating the boat. As you know, however, there are a variety of other atmospheric contaminants (including most significantly CO) on the boat, so it could have been something else entirely.

 

[Koolau]

I cannot recall specifically what the CO2 levels were, but they were relatively high. What I do recall is that I suffered from terrible headaches when we were submerged and that they were alleviated by ventilating the boat. As you know, however, there are a variety of other atmospheric contaminants (including most significantly CO) on the boat, so it could have been something else entirely.

I have always been skeptical of relatively high levels of CO2 causing anyone a problem. I'm talking a few thousand ppm - not 10's of thousands of ppm. Here is why:


Exhaled breath contains about 4% CO2. That is 40,000ppm of CO2. Living in an atmosphere of 2000 or 3000ppm of CO2 would seem trivial compared to the normal exhalation of CO2. I'm not a doctor or physiologist but I've done a fair amount of monitoring the air for trace chemicals.


My guess in the case of the submariners: The unpleasant smell of the scrubber chemicals causes head aches. Ask any person who has walked into a room where people are painting. A goodly number of folks get headaches from the "smell" - not the minor levels of chemicals per se.



A (possibly) interesting story about a "smell" occurred at Megacorp - in a library. 2 or 3 folks indicated that whenever they came into this particular library (their w*rk station) they got a headache. I took every kind of sample I knew to take and found only copier fluid vapor at very small concentrations. The copier was quite a distance from the w*rk stations.


By serendipity, it was discovered that the coat rack was located by the w*rk station and one guy placed his new leather coat there. The "smells" generated by "freshly tanned leather??" caused the 2 or 3 folks to get headaches. You can't make this stuff up!


SO. Whenever I hear "headaches" I'm more likely thinking "odor" rather than an actual chemical insult. Of course, because everyone is different, you can't rule out anything - especially when headaches are involved. YMMV

 

[RetMD21]

I cannot recall specifically what the CO2 levels were, but they were relatively high. What I do recall is that I suffered from terrible headaches when we were submerged and that they were alleviated by ventilating the boat. As you know, however, there are a variety of other atmospheric contaminants (including most significantly CO) on the boat, so it could have been something else entirely.

IMO it's reasonable to be concerned about other contaminants in homes and other settings and CO2 is a relatively easy but imperfect way to measure indoor air quality.