Jump to content

Garden office ventilation


MrMagic

Recommended Posts

Hey all,

 

As some might be aware a few years back I built a garden office/shed, insulated well and sealed it up as best as I could. Recently, when working in the office I had started to noticed feeling drowsey or 'foggy', sometimes headaches and certainly always in the afternoon (and this is without going to the pub for lunch!!)

 

Anyway, I purchased a Netatmo weather station with indoor Co2 PPM monitor (was on offer), only turned it on this morning but already it's showing Co2 being much higher than I imagined..

 

image.png.36fcbf4e324bc5f6005a680a3b37d088.png

 

Current peak is 2325ppm Co2. 

 

Now even allowing for the fact this is a consumer product so won't have the best of tolerances, it's still showing a level which I would consider 'high', and indeed various articles indicate a target of around 1000ppm or below would be best.

 

Volume is approx 20m3. I'd like to do it in a controlled fashion and where possible keep some heat in the office but open to all and any options at the moment. Windows are fixed so can't 'just open the window' ?

 

So - any thoughts on how I should go about ventilating this space?

Link to comment
Share on other sites

2 hours ago, Onoff said:

Small Ventaxia MVHR? Various models, some with humidistat etc. This link at random. I think about 70-80% efficient:

 

https://www.i-sells.co.uk/mob/prod_detail.php?Lw_wcB

 

Thanks @Onoff - I had looked at these after seeing @DamonHD s good review. My only concern was that it'd look stupid with such a long vent hanging out the side as my wall make up is probably only 150mm.

 

image.thumb.png.b15ab8bdf875b76fc412482611558b24.png

 

I guess it's either that or gas myself!... now up to nearly 3000ppm co2.. feeling pretty sluggish

 

image.png.490fe26ac986acff7cdf6fe555865a37.png

Link to comment
Share on other sites

11 minutes ago, MrMagic said:

now up to nearly 3000ppm co2

How many people are in this place, and what else goes on it it i.e. heating system, if factory connected to it.

May also be worth finding out what sort of CO2 is use.  Some only estimate based on other gases.

Link to comment
Share on other sites

@SteamyTea Just me, myself and I.. garden office, i.e. office in my garden :) Heating is via heat pump (air con unit)

 

Yeah I had wondered if it was g/CO2e but the spec sheet seems to imply it's a proper CO2 sensor (although hard to believe at a consumer price point).

 

Spec - https://www.netatmo.com/en-gb/aircare/homecoach/specifications

CO2 Meter:
Ranges from: 0 to 5,000 ppm
Accuracy: ± 50 ppm (from 0 to 1,000 ppm) or ± 5% (from 1,000 to 5,000 ppm)

 

EDIT: Heres a teardown of the internals - doesn't look likes theres any noticeable marks/codes on the sensor - https://www.fictiv.com/blog/posts/netatmo-weather-station-teardown-part-2-indoor-module

 

EDIT 2: Looks like it's a NDIR based sensor with variable results based on temperature. https://backend.orbit.dtu.dk/ws/portalfiles/portal/146097852/Untitled.pdf - Even allowing for +/- 600ppm, I've still got plenty of CO2 around it seems

Edited by MrMagic
Link to comment
Share on other sites

  • 2 weeks later...

Finally got this fitted, stating the obvious.. it only bleedin' works!

 

image.thumb.png.49a6d7ad2cee628715e7fba4567fbecd.png

 

Dotted line is the max of the previous week (prior to fitting the fan) with the solid line being yesterday. Whilst the PPM still rises to just over 1000ppm, it remains relatively stable and then the decay is much quicker with the air clearing in an hour or so after finishing for the day whereas previously it took all night for the "air to clear".

 

This is running it only on its 'fast trickle' setting of 9l/s 24x7. Next step is to try selectively switching on boost to see if I can keep the PPM down further.

 

Temperature wise, there is a slight cooling affect but nothing drastic considering it's pulling in 3degC air this morning so the heat exchange appears to be working well.

 

So in conclusion, if you seal it up tight, don't forget to ventilate right!!

Edited by MrMagic
  • Like 3
Link to comment
Share on other sites

19 minutes ago, SteamyTea said:

So how come the VentAxia is showing 1000 ppmv and the other sensor was showing 3000 ppmv?

Was it before mechanical ventilation?

 

Correct, peak of ~3000ppm prior to fitting the fan, it basically just went up and up until I finished for the day, whereas now with mechanical ventilation it appears to be holding stable at ~1000ppm with the fan running.

 

Bonfires - not too many round here, but I'm sure when I fire up the BBQ in the summer it may jump!! ?

Link to comment
Share on other sites

1 hour ago, SteamyTea said:

So how come the VentAxia is showing 1000 ppmv and the other sensor was showing 3000 ppmv?

 

AIUI, these are the same sensor: the Netatmo; there isn't a VentAxia sensor. Max values for the previous week (dotted line) are without mechanical ventilation, Feb 4th (solid line) is with VentAxia MV.

  • Like 1
Link to comment
Share on other sites

16 minutes ago, Ed Davies said:

AIUI, these are the same sensor

Right, thought the VA had a built in sensor.

I am internally debating about getting one of those cheap sensors. Just to add to all the other ones I have.

Need two really, one inside and one outside.

Link to comment
Share on other sites

  • 4 months later...
  • 7 months later...


@MrMagic Just wondering whether you have any photos of it installed? Like you, I want to introduce some ventilation into my garden room that has circa 200mm deep walls, which from the specs, don't seem to be deep enough for the unit you purchased. Did you do an interior or exterior build up to accommodate it? Cheers, Garry

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...