Sun, 14 Jun 2026 20:30:20 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248119#Comment_248119 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248119#Comment_248119 Sun, 09 Oct 2016 07:37:18 +0100 SteamyTea Posted By: fostertomWow, I thought worldwide atmospheric CO2 had only just peaked thro 400.The growing season is over, so tends to be rising until the spring.
http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.html

I am intrigued as to why the readings are so high in an unused room. Could one of you (Ed or CX) put on in an outdoor building (shed or garage) and see what the readings are.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248129#Comment_248129 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248129#Comment_248129 Sun, 09 Oct 2016 09:54:06 +0100 Ed Davies
I am a bit surprised that it's so high here as we're at (well, just passed) the global low-point for the year at the end of the northern hemisphere growing season so you'd expect NH concentrations to be comparatively low to bring the global average down. However, looking at charts of the world COâ‚‚ distribution it seems to be right. This is something I want to find out more about but suspect it's because COâ‚‚ is produced mostly on the northern hemisphere land but absorbed by the southern hemisphere ocean. Not sure about that, though.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248131#Comment_248131 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248131#Comment_248131 Sun, 09 Oct 2016 11:34:00 +0100 Ed Davies Posted By: SteamyTeaCould one of you (Ed or CX) put on in an outdoor building (shed or garage) and see what the readings are.Just put it in the shed to try that while I'm out today but the WiFi doesn't seem to reach which is a pity but not too surprising with two heavy stone walls in between. Might try something a bit more complicated later but have other things to do today.

These are the toys, by the way. Black box: USB power bank; grey box: USB hub to draw enough power that the power bank stays switched on; white box: COâ‚‚ monitor.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248133#Comment_248133 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248133#Comment_248133 Sun, 09 Oct 2016 13:07:02 +0100 CX23882
I left it in the bedroom last night - door open, 1 occupant, window trickle vent open (with Drimaster PIV unit in the hallway ceiling):
- before going to bed 780ppm
- 30 minutes after going to bed, it quickly climbed to 1100ppm
- throughout the night, fluctuating between 1100 and 1300
- quick fall off to 900ppm within 15 minutes of getting up
- left the house for 2 hours, and bedroom levels slowly dropped to around 550ppm
- changed the bedding in the bedroom - quickly rose to 1000ppm within 30 minutes of being in there
- moved it to the utility room, which I haven't been in, and got 650ppm.

As an experiment, I've hung it out of a ground floor, road-facing window. CO2 settled at around 500ppm.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248139#Comment_248139 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248139#Comment_248139 Sun, 09 Oct 2016 16:02:46 +0100 dimengineer
Just pointing this out.

I work in the pharmaceutucal industry and it is ferocious for insisting that measuring devices are properly accurate and calibrated. If they aren't, you really are flailing around in the dark... IMHO its always a good idea to distrust readings from instruments until you have build up a good set of data. Cheap stuff off Ebay can be horribly wrong....]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248146#Comment_248146 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248146#Comment_248146 Sun, 09 Oct 2016 17:25:52 +0100 djh Posted By: dimengineerAll - Calibration, Calibration, Calibration. How do you know your unit is accurate
Hire a calibrated meter for a week (about £60 IIRC) and use that to [approximately] calibrate your own.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248149#Comment_248149 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248149#Comment_248149 Sun, 09 Oct 2016 17:43:07 +0100 Ed Davies https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248150#Comment_248150 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248150#Comment_248150 Sun, 09 Oct 2016 17:59:19 +0100 tony
How does the meter measure, is it an optical device?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248151#Comment_248151 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248151#Comment_248151 Sun, 09 Oct 2016 18:11:56 +0100 RobL The assumption for most CO2 sensors is that over a few days they will sometimes be left in an unoccupied room, and so get a reasonable background reading.
If this is the type of calibration, then it can't give a useful background level of CO2, as it will always give around 400ppm as the answer.
We have a CO2 meter too - the numbers I see here seem ok. Ours normally says 500-1100ppm, easily over 1000ppm if breathing on the unit itself. By 2000ppm air feels "stuffy" to me, YMMV.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248161#Comment_248161 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248161#Comment_248161 Sun, 09 Oct 2016 20:47:52 +0100 Ed Davies
Yep, but that's a selling point of these sensors; they don't need that background low level.

http://shop.vair-monitor.com/index.php?rt=product/product&product_id=130
http://www.figaro.co.jp/en/product/feature/cdm7160.html

“We have a CO2 meter too - the numbers I see here seem ok.”

Ta, good to know.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248171#Comment_248171 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248171#Comment_248171 Mon, 10 Oct 2016 00:08:18 +0100 Gotanewlife Posted By: RobLMost CO2 meters for home use have ABC - Automatic Background Calibration.Yup mine does, took me a while to realise it had never experienced a proper outside level and had crept big time. I had to leave it outside hooked up for a week to get it back to normal. Good for "it's gone up 1000ppm" not for "Oh look it's 550, so it must be the local power stn or the approaching Ice Age"]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248609#Comment_248609 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=248609#Comment_248609 Fri, 21 Oct 2016 16:51:02 +0100 borpin
Going to turn up the MVHR though and perhaps actually check the air flows properly. Next I need to automate increasing the MVHR wrt CO2 ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250054#Comment_250054 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250054#Comment_250054 Tue, 15 Nov 2016 12:08:50 +0000 jfb
cheers]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250058#Comment_250058 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250058#Comment_250058 Tue, 15 Nov 2016 13:37:32 +0000 Ed Davies
To configure it you plug it into a USB port on your computer where it appears as a serial port. There's a Chromium app which does the setting which works well (when you chose the right one [¹]).

The main protocols it can use to push the readings are making an HTTP request with the values in the URL (usually as query parameters) or via the MQTT prototcol [²]. There are tabs in the configuration app to set up well known public “cloud” services for this or you can point it at your own computer's web or MQTT server.

[¹] http://forum.vair-monitor.com/showthread.php?tid=1

[²] https://en.wikipedia.org/wiki/MQTT]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250153#Comment_250153 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250153#Comment_250153 Wed, 16 Nov 2016 23:04:31 +0000 SteamyTea Was reading 418ppm when we went to look at it.
He made the unit himself.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250156#Comment_250156 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250156#Comment_250156 Wed, 16 Nov 2016 23:35:46 +0000 Gotanewlife Posted By: SteamyTeaHe made the unit himself. Obviously and probably a little helicopter to take the unit around the house automatically and log all the data ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250165#Comment_250165 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250165#Comment_250165 Thu, 17 Nov 2016 08:21:07 +0000 jfb https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250168#Comment_250168 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250168#Comment_250168 Thu, 17 Nov 2016 08:43:30 +0000 SteamyTea Posted By: Gotanewlifea little helicopterI did spy a drone too ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250296#Comment_250296 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250296#Comment_250296 Sat, 19 Nov 2016 09:05:10 +0000 borpin Posted By: SteamyTeaI was over at our old mate JSH's place today. He has a CO2 meter sitting in his livingroom. Was reading 418ppm when we went to look at it. He made the unit himself.I got one of the sensors he bought from him a while ago but never used it.

However, those units need calibrating regularly (one of the reasons I never used it) and that level suggest it needs calibrating as it is below the normal background levels outside. I have my sensor outside now and it is reading 450 which is (I gather) about right so unless JSH has managed to develop a CO2 capture device....]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250304#Comment_250304 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250304#Comment_250304 Sat, 19 Nov 2016 09:58:32 +0000 SteamyTea
I wonder if a lime plaster, which can absorb CO2 in some situations, lowers internal levels.
Just a thought that, I know very little about chemistry and want to know even less.

“All science is either physics or stamp collecting.” Rutherford]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250332#Comment_250332 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250332#Comment_250332 Sun, 20 Nov 2016 09:57:22 +0000 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250333#Comment_250333 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250333#Comment_250333 Sun, 20 Nov 2016 10:05:12 +0000 SteamyTea https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250355#Comment_250355 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=14342&Focus=250355#Comment_250355 Sun, 20 Nov 2016 16:42:30 +0000 gyrogear
gg]]>