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i seem to think we've done this fairly recently but cant find a thread on it that still allows me to post, so.....
we're pretty pleased with the bathroom extractor we've had in for a couple of years and we use the dehumidifier regularly. we dont seem to get mouldy corners any more, so i thought id take a punt on another 'moisture-meter' as the last one conked out on the digital readout.
google says a satisfactory reading in the house should be between 40-60%, so we've kept monitoring. now and then we get 50ish, its usually around 60% or just above tho.
bedroom is usually around 72% when we wake up, so we open windows, let a bit of breeze through until it gets too cold and we're about 60%.
today tho, i just looked late morning with the windows open and it was 79%. opened the back door too, quite a breeze coming through, it actually went up to 80%.
okay i thought, i'll stick it out in the garden and see what humidity the 'best air that we can get' is. i watched it slowly rise to 89%!!
so, im thinking that is now probably malaysian rainforest territory and my meters not lasted more than a few weeks again. that right? or could that reading on this balmy, breezy day actually be accurate?
cheers
yes, ive just been googling, seems at the moment we have a higher humidity than both malaysia and thailand! 😮
so it would seem that opening windows and letting the air flow through when its that high just makes things worse. dehumidifier it is then, and windows closed!
any other tips that might help keep it down throughout the house when its so high outside?
This may be obvious but its a relative measure. Cold air can hold less moisture than warm air. So if you want to reduce the relative humidity you can warm the room up.
It's quite common to have high humidity with cold air. Our standard atmospheric conditions at work used to be 25C 50% RH or 10C 80% RH.
This may be obvious
I think not given the OPs incredulity at outside humidity.
I think not given the OPs incredulity at outside humidity.
😆correct!
id maybe expect it on a rainy day, but i was pretty surprised that on a dry, warmish, breezy day it would be that high. i would always have expected open windows and a breeze to improve conditions in the house.
you live and learn, even at my age.....
It's one of those things that I'd never given any thought to until we were doing something at work that depended on the total availability of moisture not the relative amount. Someone gave me the diagram and I had the same reaction as you.
I’ve driven myself to the brink of insanity using moisture meters in the house.
Today we also noticed an increase in internal humidity when we opened the windows 🤦🏻♂️ to air the house - curse you warm wind 🌬
Humidity accuracy is not great. I remember attending a climatic testing course 20+ yrs ago and I think it is +/5% at best. Anyone who tells you anything different is talking crap.
This may be obvious
No, it hurts my head.
Say I have a Meaco dehumidifier in my cellar, where I keep (say) bikes and tools and shizzle. In order to stop things rusting, do I set it to [1] which is cool or [2] which seems to be heated?
I’m sitting in bed and due to a smart thermometer/ hygrometer can tell you that the humidity in our shop is 73.2%. That’s the highest since we’ve had the gadget.
Today we also noticed an increase in internal humidity when we opened the windows 🤦🏻♂️ to air the house – curse you warm wind 🌬
well im pleased its not just me thats been bamboozled by this. got to say im really surprised at how high it is when its not raining (or even looking like rain). just googled the humidity in my local area and its 90% today!
so......still not sure if its better to have the windows open and have 'moist' air moving through the house so theres no 'dead air' that can grow mould, or batten down the hatches and hope that the (slightly) dryer air inside is of greater benefit (plus dehumidifier in hallway and room doors open). thoughts?
Humidity accuracy is not great. I remember attending a climatic testing course 20+ yrs ago and I think it is +/5% at best. Anyone who tells you anything different is talking crap.
well after getting the meter and seeing that its actually 20-30% higher than i would have guessed, im happy with a 5% variant in accuracy.
What you need is a Sling psychrometer, accurate to 2%Rh from memory. You look like a demented football fan from the past though.
In a different life I spent weeks calibrating humidity sensors at a large hospital wth one.
I got a few Bluetooth cheapies from Amazon.
Has at app that reads them. And the are data loggers too.
One outside, one inside and one in the basement.
They can be hacked aswell apparently so might have a play with some sort of automation.
got to say im really surprised at how high it is when its not raining (or even looking like rain). just googled the humidity in my local area and its 90% today!
you need to get your head around the fact it’s a relative measurement that depends on the temperature of the air. Warm air can hold more moisture so imagine a cube of outside air at 11degC and 90% RH. Bring it into your house and warm it up to 19degC and that same cube of air will be ~55% RH.
hmmmmm......mebbes getting a bit too techy for my little brain now. i suppose from historically having mould problems on ceilings in places where i didnt expect it (mould right above an open window in a bathroom?? mould around the air vents that we had installed in our bedroom to prevent mould on the ceiling??), im just more interested in doing what i can to prevent mould growth. and that would appear to be aiming for the sweet spot of around 50% humidity inside our house, irrespective of temperature outside or in.
so, readings in the house of >70% and finding out that the air i thought i could bring in to help reduce this is actually 90% rings alarm bells.
EDIT: as its so blowy outside ive opened all the doors and windows and got a good bit of wind blowing through the house this morning, just feels the right thing to do whether the meter reading creeps up or not.....
90% outside is not 90% inside…
90% outside is not 90% inside…
even when the doors and windows are open, equalising the temperature? at present my moisture meter says its 16 degrees inside, its probably about the same outside. draught blowing through the house, 75% moisture.
and with energy prices sky high at present we're trying not to use the heating that much, so theres not going to be toooo much difference in temperature in/out during the day. just tend to put it on for a few hours in the evening then off again.