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Indoor Humidity

  • 11-02-2021 10:19am
    #1
    Registered Users Posts: 1,640 ✭✭✭ green123


    What is your indoor Humidity currently?

    With this East Wind it is at a very low level for me.

    Currently 41%.

    Sometimes it is up in the 80s for me indoors depending on the weather.


Comments

  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 16,106 Mod ✭✭✭✭ DOCARCH


    My Netatmo is saying 51%.


  • Registered Users Posts: 17,664 ✭✭✭✭ JCX BXC


    47% here

    Not something I'd ever have really considered before!


  • Registered Users Posts: 7,255 ✭✭✭ kenmc


    Surely it also depends on your house and whether you have mhrv or Windows open or wall vents, your heating level and if you've been cooking\showering\drying clothes etc?
    For what it's worth, my kitchen currently 34%, high of 52 over last 7 days.


  • Registered Users Posts: 8,199 ✭✭✭ Gaoth Laidir


    Quoting relative humidity means nothing unless you state the temperature too. Then the r.h. depends on the dewpoint outside.

    In the past few days, dewpoint has been down around -5 °C. For a room that's at a constant 22 °C, that relates to a r.h. of around 16%. If the room is 18 degrees, r.h. is more like 21%.

    In summer, with a typical dewpoint of 15 °C the same room at the same temperature of 22 °C would have a r.h. of 65%, or 82% if it's at 18 °C.

    That's why people tend to exaggerate high humidities in hot countries. "It was 40 degrees with 100% r.h." That's impossible, as it would require a dewpoint of 40 °C, which has never been recorded. Any 100% r.h. value was probably from early morning, when dewpoint and temperature were probably both around 25 °C, which is widely the case in many warm countries.


  • Registered Users Posts: 1,376 ✭✭✭ Reckless Abandonment


    I got 39% humidity inside. Its a killer for indoor plants


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  • Registered Users Posts: 1,640 ✭✭✭ green123


    kenmc wrote: »
    Surely it also depends on your house and whether you have mhrv or Windows open or wall vents, your heating level and if you've been cooking\showering\drying clothes etc?
    For what it's worth, my kitchen currently 34%, high of 52 over last 7 days.


    Yes, all of that matters.
    Thats exactly what affects indoor Humidity.

    Most of that stuff you can control somewhat.

    But even when you are doing your best to control humidity, keeping the stuff you mention in mind, the weather has the biggest influence.

    Makes me wonder if there is there any point in getting a Dehumidifier?


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 16,106 Mod ✭✭✭✭ DOCARCH


    green123 wrote: »
    Makes me wonder if there is there any point in getting a Dehumififier?

    Or a humidifier?

    Ideally indoor humidity should be between 40 and 60% for a healthy environment.

    I have a humidifier running in my office, in winter/when heat is on, to increase the humidity.


  • Registered Users Posts: 17,664 ✭✭✭✭ JCX BXC


    DOCARCH wrote: »
    Or a humidifier?

    Ideally indoor humidity should be between 40 and 60% for a healthy environment.

    I have a humidifier running in my office, in winter/when heat is on, to increase the humidity.

    Could you not say, boil a kettle for the same effect?

    Granted not a great option when you need it for any length of time.


  • Registered Users Posts: 1,640 ✭✭✭ green123


    DOCARCH wrote: »
    Or a humidifier?

    Ideally indoor humidity should be between 40 and 60% for a healthy environment.

    I have a humidifier running in my office, in winter/when heat is on, to increase the humidity.

    I am more interested in a Dehumidifier.

    I thought that I might have a bit of a damp problem because I often see humidity in the 70s or 80s.

    But it was nice to see 40s for the last while.

    And now I am beginning to wonder if I actually need a Dehumidifier.

    I probably don't have damp and the high humidity readings are all down to weather conditions


  • Registered Users Posts: 20,855 ✭✭✭✭ Alun


    I remember when I lived in Germany and the Netherlands we had little porcelain or plastic containers that hooked over the radiators which you filled with water to increase the humidity. I don't know if you can get anything like that here. Probably cheaper than an electrically powered humidifier.


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  • Registered Users Posts: 1,640 ✭✭✭ green123


    Quoting relative humidity means nothing unless you state the temperature too. Then the r.h. depends on the dewpoint outside.

    In the past few days, dewpoint has been down around -5 °C. For a room that's at a constant 22 °C, that relates to a r.h. of around 16%. If the room is 18 degrees, r.h. is more like 21%.

    In summer, with a typical dewpoint of 15 °C the same room at the same temperature of 22 °C would have a r.h. of 65%, or 82% if it's at 18 °C.

    That's why people tend to exaggerate high humidities in hot countries. "It was 40 degrees with 100% r.h." That's impossible, as it would require a dewpoint of 40 °C, which has never been recorded. Any 100% r.h. value was probably from early morning, when dewpoint and temperature were probably both around 25 °C, which is widely the case in many warm countries.

    This is interesting, thanks for that explanation.

    Any thoughts on the benefits of a Dehumidifier?

    I am thinking now that I might not have a damp problem at all.


  • Registered Users Posts: 8,199 ✭✭✭ Gaoth Laidir


    green123 wrote: »
    This is interesting, thanks for that explanation.

    Any thoughts on the benefits of a Dehumidifier?

    I am thinking now that I might not have a damp problem at all.

    Dehumidifiers are absolutely useless unless you have them in a very sealed room or a cupboard. They just can't compete with natural atmospheric humidity. If that rises then nothing can take the water out of the air at a high enough rate to overcome that.

    If you have a damp problem at home then it's because the area is getting too cold, so its r.h. is rising to 100%, not because any water vapour is being added, just that the area has cooled down to its dewpoint.

    The radiator yokey things that are used on the continent to humidify rooms may or may not work, again depending on how sealed the room is. These are generally small containers (~100 ml) filled with water.

    A dewpoint of 5 °C relates to a water vapour mixing ratio (concentration of water vapour in the air) of about 5.4 g/kg of air (i.e. about 1 teaspoon of liquid water in a volume of around 0.86 m³). To rise the dewpoint to 10 °C means you need to add a further 2.2 g/kg of water vapour. For a typical 4 x 4 x 2 (32 m³) room you'd need to add around 82 g of water vapour, assuming the room is completely sealed. Difficult to do that in reality.


  • Registered Users Posts: 9,775 ✭✭✭ Effects


    I have a studio space, that isn't massively in use at the moment due to covid. Temp over the past while has been 8°C and 48% humidity.
    I generally keep my smallish dehumidifier running 24/7 in the space. It's got thick stone walls. I find it pulls a couple of litres a day out of the atmosphere. Which is good for the paper and equipment I have in good condition.

    At home I have MHRV, and find humidity is around 60% a lot of the time. We still get issues with mould in the wardrobes and storage areas though.
    System was put in by some cowboys, so I need to look into getting it properly balanced as well.


  • Registered Users Posts: 20,855 ✭✭✭✭ Alun


    I just found some of those radiator humidifiers on Amazon, different sizes but seem to be around 500ml. Might get a few and see if it improves things a bit.

    We've got the opposite problem to others here in that humidity is around 17-20% at the moment.


  • Moderators, Home & Garden Moderators, Science, Health & Environment Moderators Posts: 16,106 Mod ✭✭✭✭ DOCARCH


    Alun wrote: »
    We've got the opposite problem to others here in that humidity is around 17-20% at the moment.

    That would suck you dry! :eek:

    As above, between 40% and 60% is what's comfortable/healthy for indoor environment.


  • Banned (with Prison Access) Posts: 2,254 ✭✭✭ Nqp15hhu


    39%.


  • Registered Users Posts: 6,033 ✭✭✭ Oneiric 3


    Davis V2 console says 48%. Davis weatherlink console says 39.5% (which is right beside the V2) and La Cross digital thermo in hallway says 34%. Accurate humidity readings are far harder to capture those of basic temp.

    New Moon



  • Registered Users Posts: 5,362 ✭✭✭ highdef


    Home Office, temp is 24.3°, humidity is 28%


  • Registered Users Posts: 20,855 ✭✭✭✭ Alun


    I've just bought a humidifier. I placed the device I was seeing values of 20% on (OWL energy monitor) next to it and there's a huge difference between the readings. The OWL is now showing 35% and the humidifier 62%.

    Not sure what to believe, but purely based on health symptoms like itchy eyes and throat and dry flaky skin, I'm still sure it was too low. Remains to be seen if the humidifier helps in any way.


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