Replies

1. GBA Editor
   Martin Holladay | Jul 10, 2019 09:21am | #1

   Koichan,
   Briefly, the answer is that there is no danger that you will deplete the level of oxygen in your home to dangerous levels. (Air is about 21% oxygen.) However, there are conditions where indoor levels of carbon dioxide can rise to the point where clear thinking is (possibly) affected. You are aiming to achieve 1000 ppm of CO2 or less.

   For more information on ventilation -- which is a huge topic -- see the many articles listed on this page: "Ventilation."

2. Expert Member
   BILL WICHERS | Jul 10, 2019 10:50am | #2

   Your dehumidifier won’t do anything to affect oxygen levels in your home. Dehumidifiers work by making a cold surface and condensing water out of the air. The only thing the dehumidifier will do is remove moisture from the air (some of the moisture, not all of it), and add a little heat into the space. Dehumidifiers do not alter the atmospheric gas makeup (oxygen, carbon dioxide, nitrogen, etc).

   Bill

1. 
   Jon_R | Jul 10, 2019 11:52am | #3

   In other words, if you were happy with air quality with just AC, you will be even happier with AC + dehumidifier.

3. 
   Koichan | Jul 11, 2019 08:20pm | #4

   Thank you all for your comments. I hope this is my last question on this topic. what is an easy way to purge carbon dioxide without a high energy penalty? would it be sufficient to open windows whenever you can when the temp and humidity outside are low, or crack windows even the temp and humidity are high outside?

4. 
   exeric | Jul 11, 2019 11:40pm | #5

   I agree with Martin and Bill (Zephyr). In a hot humid climate one really should keep the windows closed and use AC. AC is already a dehumidifier and if you need a dehumidifier in addition then you've probably got other structural problems in addition. But you live in the deep south where it's just stacked against you in summer. Ordinarily a dehumidifier seems just a band-aid if it's used in addition to AC.

   Keeping all the windows closed in outside hot muggy conditions just seems like good sense. In a situation like that an ERV is a good investment to decrease the CO2 buildup. They can be expensive initially but they won't consume a lot of electricity like a dehumidifier would. I lean towards the idea that there is something ineffective with the AC to need a dehumidifier if its in addition to AC. If the dehumidifier stands alone then that's a different story. Then go for it.

   Edit: due to the fact that I didn't see he actually lives in the deep south.

5. GBA Editor
   Martin Holladay | Jul 12, 2019 05:23am | #6

   Koichan and Eric,
   I might have misunderstood, but it sounds as if Eric's response implied that the use of an ERV can lower indoor humidity levels. It can, but only in winter. In hot, humid weather, an ERV won't lower indoor humidity levels. Only an air conditioner or a dehumidifier can do that.

   Q. "What is an easy way to purge carbon dioxide without a high energy penalty?"

   A. What you need is a ventilation system. "Easy" means inexpensive -- for example, a central-fan-integrated supply ventilation system or an exhaust-only system. But "easy" is in conflict with your other criterion: "without a high energy penalty." For the lowest energy penalty, you want an HRV or an ERV -- and that costs a lot to install (and is therefore probably not "easy").

   All of your options are laid out in the following two articles:

   "Designing a Good Ventilation System"

   "Revisiting Ventilation"

1. 
   exeric | Jul 12, 2019 12:23pm | #7

   Martin,
   No, I was answering off the implied info that keeping windows closed would decrease humidity in combination with an AC or a dehumidifier. Doing that in turn would increase CO2 levels. So it's best to use a ERV to get fresh air without increasing humidity. Also I suspected that perhaps opening windows was increasing the humidity inside and if he doesn't do that then he might not need a dehumidifier. I'm not there but that was my hope.