How to manage high co2 in the home on the cheap.
October 2, 2014 5:47 PM   Subscribe

I am coming to mefi for some out of the box ideas for remediating excess co2 in the home. It's high enough that I believe its causing problems. However, neither my husband and I are working, so can't afford the correct solution. I'm hoping metafilter can help with some out of the box ideas to deal with this cheaply temporarily.

Earlier this summer, I posted about a surprising co2 reading.. I think it may be the cause of some of my health problems, at least complicating things. I need to fix it before winter in Wisconsin sets in and can't remediate with open windows.

The cost of getting a Heat Recovery Exchanger installed is $3500 to $7000, and that is just far beyond what we can afford. As it is, we're teetering on a very bad place financially, and until my husband is working again, that isn't going to change.

The readings this summer got north of 2000ppm when the house was closed up. I'm using a withings scale with the co2 sensor, and I strongly suspect it's accurate, but haven't wanted to spend the money to verify with a second meter/reading. However, I've done a few things that have lead me to believe it's accurate. When I take it outside, or within a few hours of opening the windows, it drops to the level of "outside air." (around 350ppm outside, around 400-450 with windows open).

I've had numerous health issues, but fatigue has been a big part of it. I'm wondering if high co2 in the home isn't playing a part. I quite literally forgot about it after the above post (I blame excessive co2 levels! (only half joking)) But after having the house closed up for a while and running ac, I opened the windows and felt SO MUCH BETTER. And then I remembered the co2 readings, and sure enough, over the course of the summer, when I had the windows closed and ran ac, the co2 would start building up within a day or two of the home being closed up, and would hover between 1500-2000ppm. Those levels are correlated with fatigue.

A Heat Recovery Ventilator is probably in order BUT here is the sticky part. I'm just straight up broke. I'm not working, my husband was let go from his job, some months ago, and we're barely scraping by. I can keep the windows open for right now, but we're creeping up on winter, when the house will have to be closed up for months on end. If the winter is anything like last, cracking the windows won't even be an option (I tried, the window froze open).

Last winter I felt worse than I had, well, ever. I have a chronic condition, but felt SO MUCH WORSE. My doctor and I chalked it up to the cold. However, I'm now wondering if having the windows closed from November to April, and the resulting CO2 build up, was part of it.

I'm hoping mefi might have some creative ideas for ventilating the house, at least until spring, when hopefully our financial situation improves and it can be addressed properly.

We don't know where the co2 is coming from, but I suspect that it is just from the metabolic process of the creatures living in the house. Our house is 2000sq/ft, but we have the two of us, two dogs, 3 cats, and a bird. The confusing part is that the house is drafty. We thought that perhaps one of the combustion appliances was to blame, but as a test, we closed up the house for a few days, rarely ran the hot water heater, and didn't have any heat on, and sure enough, it crept up over the course of two days to about 1100ppm. I'm sure it would have gone higher had we continued to leave it closed. We tried a few things then, like airing the house out, closing it up again, running the hot water to see if that would cause the co2 to go up rapidly, and it doesn't.

We do have a co monitor, as it was suggested that the co2 could be part of a combustion or venting problem, but co seems fine. We have a monitor, and we just replaced it at the end of spring. The old one was at the end of it's service life.

Some ideas my husband and I have come up with to get the ball rolling
- opening the attic crawlspace - the attic is ventilated, but I can't imagine that it wouldn't drive the heat bill up.
- Buy a heat recovery ventilator, and just venting it in a window (some of the units can be picked up for $500-$600, which I think we could swing), and later having it done correctly.
- Installing a vent in the window to blow air out, relying on a leaky house to pull in fresh air. However, I just learned about what a danger negative pressure in a house can be.

We also did discuss plants, but the general consensus seems to be that they don't actually consume that much co2 in a home scenario.

So hive mind, how do we survive this winter and have livable fresh air?
posted by [insert clever name here] to Home & Garden (12 answers total) 1 user marked this as a favorite
On the chance that some of your CO2 is seeping from the ground, I would not install a vent to blow air out the window, that would just suck more CO2 out of the ground. If you think that there might be seepage from the ground into your basement, you could look at the kind of basement ventilation units that are designed for radon problems.
posted by beagle at 6:42 PM on October 2, 2014

It sounds like your options are
1. Blow your old air outside.
2. Suck in new air.
3. Remove the CO2 from your existing air.

You said you think option 1 (negative pressure) is dangerous. Number 3 will drive up your heating bills and even so you'll likely be cold. I think the answer is number 3. Plants may not consume "that much." but it's not clear that you need to consume "that much." You don't need to get rid of every CO2 molecule, just to have fewer of them. Get lots of plants and you should have fewer of them. Find fast-growing plants as these will suck up the most, says the interwebs.
posted by If only I had a penguin... at 6:43 PM on October 2, 2014 [3 favorites]

When I lived in a cold climate, I would still open the windows in the bedroom at night (unless it was directly snowing inside!) and would ventilate the rest of the house once a day by turning off the heat and opening doors and windows. I actually wasn't aware of CO2 pollution indoors, but I just liked fresh air. I don't know where you live and so windows really may not be an option, but could you at least leave the door open for a few minutes a day? And yeah, definitely get plants.
posted by three_red_balloons at 8:15 PM on October 2, 2014

The Wisconsin Department of Health Services has a link to the Home Energy Plus program. One of the Home Energy Plus initiatives is the Wisconsin Weatherization Assistance Program-- based on the description it looks like it goes beyond just helping to pay for energy and addresses your situation: "Correcting health and safety hazards and potentially life-threatening conditions is the first consideration in WAP activities."

Here are the income eligibility guidelines. Even if you aren't eligible, they may be able to point you to another agency that can help you get the heat recovery ventilator before winter sets in.
posted by scarnato at 8:37 PM on October 2, 2014 [6 favorites]

[ICNH]'s other here; I know that growing plants are of questionable value, but as I see it, it can't hurt. So we use bamboo, because it's fast growing, dandelions, lettuce or squash, because we can feed it to the tortoise, and marijuana.

I figure we can then sell the pot, and use it to buy a properly installed air/ heat exchanger. And if we're caught, I can hope that the police have enough of a sense of humor to let us off with a stern warning about selling schedule 1 drugs for home improvements.

(kidding, of course, but I suspect getting information about how to realize one of these in our house is going to be the answer that solves this problem.)
posted by quin at 9:43 PM on October 2, 2014

You may be able to have an HRV installed and rent it, rather purchasing it and owning it. (I realize renting doesn't make sense in the long run, financially.) Call around.

Buy a heat recovery ventilator, and just venting it in a window (some of the units can be picked up for $500-$600, which I think we could swing), and later having it done correctly.

I think you need to 'balance' the fans in HRVs to avoid negative pressures and so on, along with installing inlets and outlets on various exterior walls in the right way to deal with differing wind pressures. Technicians up here are trained, probably licensed, and carry manometers.

Since you guys are in a sticky spot, double check with people in an HVAC forum to see if this is feasible.

posted by sebastienbailard at 11:30 PM on October 2, 2014

We also did discuss plants, but the general consensus seems to be that they don't actually consume that much co2 in a home scenario.

You can put the sensor near your plants and see if they're helping. I'm a bit skeptical, but data is the important thing.
posted by sebastienbailard at 11:33 PM on October 2, 2014

Don't open up a designed-to-be cold attic to the warm house, you'll damage your roof.

Can you air the house out for 15 minutes a day? Open all the doors and windows and get a good cross breeze going, then just close it up and turn the heat back on.
posted by fshgrl at 12:50 AM on October 3, 2014

I would try an experiment, open up the highest and lowest window in the house a bit to create a constant air leak, one which the furnace will have to supplant to keep you warm. Do it and compare how you feel along with the nightly energy usage (natural gas / electric meter) to get an idea of what this will cost you. You might find for just a few dollars more a month you get a low CO2 reading. Also do you have a Carbon Monoxide detector in your house?
posted by nickggully at 5:56 AM on October 3, 2014

Could you possibly rent out the house (disclosing the problem to the renter) and rent a different place temporarily, until you have jobs and the savings to get the equipment you think you need?
posted by three_red_balloons at 9:15 AM on October 3, 2014

I am not a Certified Industrial Hygienist.

That being said, I'm passably familiar with air assessments, and one thing that stands out to me is that you don't know it's the CO2 causing your symptoms -- you just know that higher CO2 correlates with your symptoms. That's totally understandable, because it's the CO2 that you can measure.

Indoor air folks generally use CO2 measurements as a useful way of gauging roughly how much stale air is building up over a day -- you measure CO2 in the morning, let in the humans, and then measure how much higher it gets. Rapidly rising CO2 is a sign of poor ventilation.

From that, I'd say you have evidence that your house is poorly ventilated. However, that doesn't mean that the CO2 is what is causing your health problems. There are a lot of other things that will build up in a poorly ventilated space -- VOCs from offgassing building materials, mold spores, dust, particulate, etc, etc. Any one of those could be either the primary cause of your symptoms, or could at least be contributing.

So one thing I would suggest is looking into other possible causes.

Depending on your insurance situation, you could get tested for allergens that might be contributing. (Even if you've been tested before -- I once managed to develop a new allergy in about 12 months, as confirmed by two scratch tests and observations. It happens.)

You can also just take the approach of allergen reduction without testing. Inspect your house for water infiltration or mold growth. (You mention that part of your house is subgrade, which raises your chances of getting mold.) In your bedroom, vacuum, dust, wash all bedding in hot water and dry on hot. (That last one alone makes a huge difference for me.) Run a cheap Wal-Mart air filter (available for $30) to cut down on dust and particulate. If you use any scented products, candles, air fresheners, etc., remove them. Remove any bedding with feathers. Try keeping one room pet-free.

Alternatively, you could bring your scale to a friend or family member's house, and see if you can find someone else with indoor CO2 levels as high as yours. If you can be exposed to similar CO2 levels in someone else's home without showing symptoms, that raises the probability that the CO2 is just a proxy measurement for the real issue.

Incidentally, I'm not writing off CO2 as a potential cause -- it totally is, and there's evidence that it affects people at lower levels than previously realized, and certainly at levels that you're seeing. HOWEVER, I do think it's worth considering other potential causes, if only because some of them may be easier and cheaper to address than the CO2 issue.
posted by pie ninja at 10:19 AM on October 3, 2014 [4 favorites]

Response by poster: Thank you for all the ideas. To address some suggestions:

beagle: I didn't consider co2 seepage from the ground, but now I see it is a possibility. Our house is a bi-level, with half the livable space partially below grade.


If only I had a penguin... and sebastienbailard: The plant idea might be necessary and should be inexpensive to test; but I'm ultimately suspicious that it will not work well, and will risk bringing allergens, like mold, in. Still, I will probably try it with some inexpensive bit bright power compact bulbs.

three_red_balloons: Cracking the windows in winter doesn't seem practical. I tried that a few times last winter, and I kid you not, the windows froze when I did it. (I didn't have any sense of co2 being a problem, just that the house was stale) Now, that was probably the coldest winter in 20 years, but it was the extra cold winter that caused the house to be shut up for so long. And having no real way to know what this winter will bring means that if I don't do something about it, I could be heading for real trouble. Plus, previous winters where I was able t open windows more frequently weren't great, just not as totally horrible.

scarnato: The home energy plus program is something I hadn't considered. I will look into it BUT I fear that the answer will be to seal the house more tightly, compounding the problems. My suspicion is that since data about high co2 levels and health is emerging, that it in and of itself won't be considered a health hazard. But it won't hurt to inquire, so I will.
sebastienbailard: I didn't consider the possibility of renting/leasing an HRV system, but that's a damn fine suggestion. I'm going to see if we can find any place that does it.

As for "installing" it ourselves, my thought was literally to put plywood in a window, and cut holes for the intake and exhaust, and use it strictly as a way to bring outdoor air into the house via a window. Only instead of an open window, using this to equalize the temperature. I didn't consider balancing, but I suppose a simple way would be to just have a dampener on the exhaust side. Maybe? Finding an HVAC forum is probably a pretty good idea in that regard as well.
fshgrl: Thank you for the thoughts about the attic. I didn't think about the effect on the roof, but you are right, it's not designed for that.

Airing for 15 minutes a day might be possible? I'd be afraid of the windows freezing though, I don't know how quickly that could happen if it's -20 out. Our windows are old and sticky, and last years attempts a couple times the windows weren't open that long and they still froze.. We were able to break them lose with a hammer and warm air, but it wasn't fun. The front door is the only place I wouldn't expect to have trouble freezing.
nickggully: I don't think any experiment with energy usage and leaving the windows open a crack would apply to what it will be come winter. Right now, the coldest nights are 38F. Winter can easily get to -30F and much more significant wind.

I do have a carbon monoxide detector, and it's fairly new. We replaced it in the spring, when ours reached it's expiration date (which has an audible alarm scared the hell out of us until we saw the unit had a hard date when it would no longer function.
three_red_balloons: We've considered renting. We've been looking into it, and don't think it's feasible for two reasons; I don't think I'll be able to find some place willing to let us take the pets with. I also don't think renting out our house will be feasible - we live way way way out in the burbs and there aren't going to be a lot of people interested in renting a house this size that wouldn't otherwise just buy a house. That, and we have a lot of little problems that need to be repaired. Nothing over the top, but it all adds up and any reasonable tenant would want them fixed.

pie ninja: I've been wondering about non-co2 contaminants in the home for a long time. And I'm not suggesting it's not possible, but have some reasons to think it's a non-issue, or at least not as much of an issue as the co2 is. Part of brought my thinking to this way was some happen-stance. It started with going to an aquarium conference where a speaker mentioned injecting co2 to grow really dense algae cultures in his lab. Shortly after that, my 19 year old cat peed on my Withings scale shortly before he passed. I got a replacement withings scale, and the new model now has co2 readings. Which were around 2000ppm when I first set it up - so I reached to the speaker at that talk and joked "hey, that's why my algae looks so great." And we go to talking about it; he said that they monitor co2 closely because of the negative effects they seen in the lab when it gets too high. Started doing my own research, and while different sites discuss different ranges, all suggest negative effects start around 600-800, and 1000 is at least correlated with fatigue.

So the point is, there could be a issue with allergens also causing the problem. I do, in fact, have allergies. I've had doctors tell me up, down and until tuesday that allergies won't cause fatigue. Now, allergy suffers tend to disagree with this across the board, and so do some medical professionals. BUT - one thing I tend to really struggle with is tree pollen in the spring, and I felt better with the windows open in that time, and mold in the fall, which I'm again feeling better with the windows open.

Mind you, I don't think that is the whole cause to all my health problems, but I think it might be a factor that is making my quality of life worse if it is inducing fatigue. I think that finding a way to get fresh air into the house year round will make a big difference.

--- I am having to close the house up right now because the temperature is dropping fast and is going to stay pretty cool for the next few days. I think I am going to try two things - plants and an exhaust fan. I haven't decided which first; but with plants I'm going to set up a couple bright lights and a few plants, and see if there is a noticable drop in co2.

I initially dismissed the exhaust fan because of the risk of depressurization and exhaust coming back into the house, but reconsidered it for a couple reasons. One, my house really is sieve like in it's draftiness, so I suspect it will pull air from the drafty windows before pulling exhaust back into the house. But two, since starting this post, I've been looking into people using them for humidity control and not having any real issues. I am thinking of getting a second carbon monoxide alarm just as a precaution. If it does pull co2 from the below grade areas, then I would expect to see the co2 increase, which should be easy to monitor.
posted by [insert clever name here] at 5:53 PM on October 3, 2014

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