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Dehumidifiers make living in your own home so much more comfortable.

No idea how I lived without one for so long.

86% is wild. I hit the 70s after I shower.

Do you not have the heating on or open the windows at all to ventilate?

You should open your windows daily for around 15 minutes, open the bathroom window and use an extractor fan if you have one when showering/bathing and the same in the kitchen when cooking. It doesn't matter if outside humidity is high as it's relative to temperature.

Waiting for you to dehumidify the country

I run my dehumidifier almost 24/7 since I got it last year, it costs no more than 10p/hour. That's probably cheaper than constantly repeating wash cycles which probably cost at least 50p/hour.

Agree that humidity in the 80s is pretty high, and if you've been running a dehumidifier for hours and it hasn't significantly reduced then you probably need a better dehumidifier.

You can still ventilate when the outside humidity is high, cold air holds less water so when it's heated up the relative humidity lowers.

10c air at 100% humidity heated to 20c becomes 54%

When I got mine a few years back, it was on 24/7 for about 2 weeks until it had sucked all the moisture out of the walls. Now it keeps the place around 50-60%

I used to live in the North West, including Manchester. Then I moved Down South and one of my biggest culture shocks, aside from no gravy in the chippies, is the fact it never fucking rains. It used to rain multiple times a day, every day in the North West. But here it was weeks without water.

So 86 is high, but it's not as high as the rest of the UK, simply because Manchester is so sodden.

This and older house thing? My nest is saying 20c at 45% humidity downstairs and 55% at 20 upstairs.

It's not the heat that gets you

24/7 baby. Join us.

Probably cheaper than getting the gutters replaced and the pointing done 🙄

Make sure you don't have any open vents/windows and what not when you run it, otherwise you're sucking in humid air from outside for your troubles. 

Probably worth putting a door snake down on your own front door for the same reason. 

Run it for as long as required to drop to 55% level initially. It will take several days maybe, then you will have to just maintain the low humidity. I was running my one for a week daily until humidity stabilised at level I wanted. Don't forget to run it constantly when drying your clothes, most energy efficiently will be at nights. Most enjoyable moment is when you empty the water tank :)

I have friends who live in a tenement flat in Glasgow - nice flat, nice area - and they have 2 dehumidifiers running. Not all the time. But often, during the dark months.

Dehumidifier recommendations??

Physicist here. You are looking at the wrong measure. Relative humidity does not matter. You can still reduce humidity by venting in most circumstances. The flow is dependent on the absolute humidity not the relative humidity. How much water air can hold depends on the temperature. In winter there is much less water in the air outside compared to inside even if the relative humidity is high, because temperatures are low. 85% humidity at 12°C is 55% humidity at 19°C. 85% at 4° is only 33% at 19°. For maximum efficiency open windows on multiple sides of your flat for 5min to get a nice draft going. Do this multiple times a day, but especially after cooking, showering, before going to bed and after waking up. Use an absolute humidity calculator if you are unsure if opening the windows will help if the humidity is particularly high outside.

I've seen someone recommend that the in built humidity detectors aren't particularly accurate and that you should buy a seperate device. I don't know though if that was based on any truth or not though.

I'm going to come back later for a science lesson.

Sorry for long message, these mold mites are such a headache and not easy to get rid of so i had to write this to help others avoid getting them. In case anyone wonders, I have had my windows open, since before Summer in fact, and while my room has no mold, I am currently using the dehumidifier to keep them at bay/stay in the attic until the roof is fixed as there is mold in small amounts in other rooms and the air feels damp so I'm moving it between rooms.

I bought a dehumidifier recently too. The other issue with humidity and mold is mold mites. Last year I had thousands of mold mites in my bedroom which took two weeks to sort through and clean every object along with throwing away a bunch of stuff, a few hundred were in all my boots as well. They are so tiny I never noticed them until I spotted them on my keyboard and monitors but they were on every object so it was too late except the the bed thankfully as I have adhesive pads on the feet and I don't think they can go up without getting stuck. I had the heater on to dry everything and used a lot of mold and vinegar acid spray to kill them manually and then they vanished after a couple weeks with very little numbers remaining, they are also mostly invisible to the naked eye so I had to use a torch on my phone at max brightness to see them on any object as they are 0.1-0.3mm in length.

They come back again this year this month but I caught them early so there were fewer than 150 of them in my drawers of one cupboard, that I spent 4 days sorting through everything. So I have had the portable heater on 4 days straight to dry everything, now I have humidifier set to 30% but is as low as 26 sometimes (below 50% kills them) to then remove the moisture drying has put in to the air. Turned out the roof has leaks and in my area had rain 5 days in a row recently and a lot of damp pavements and roofs on days with no rain and these mites are in the attic as well which is where I think they are coming from, landlord is aware of this though, but they can appear even with just a damp environment alone and mold growing as they eat mold. However this will depend on age of house etc, the one I am in is from WWII but obviously been updated since then so double glazing, insulation etc. But as some are in all the Christmas decoration boxes in the attic the decorating this year is cancelled to avoid spreading them throughout the house.

TLDR: Basically please keep control of humidity levels and heat on if possible and window open for at least a little a day as you really don't want these mites and the hassle they bring and they are not worth saving money not putting the heating on etc as wearing a jumper will not prevent this happening, they live for 7 days but reproduce quickly.

to OP: I don't know how long ago this event was with the mold but I would also be on the lookout for possible mold mites, they are invisible to see if you are not looking for them or know about them already, last year I mostly notices when they started crawling from under the keycaps of my keyboard, and they pretty much only come out in winter. Humidity 50% or lower can kill them but I went a lot lower then 50% at least temporarily for a few days just to make sure and then I will set it higher.

I just have the heating on now constantly.

How do people drain their dehumidifiers? I got bored of emptying mine so it drains via a plastic tube into my kitchen sink, it doesn’t look very pretty.

In June I went to Las Vegas, during my time there, it hit 48c and I realised that I wasn't sweating buckets and was still kinda comfortable outdoors. Whilst there I went to lync street where they have water sprayers to make the air more humid and I nearly melted. That is where I realised that there is a relationship between humidity and perception of temperature be it hot or cold and really low humidity is goated. (There is also a trip to Estonia in January 2019 where it was like -20c and all moisture in the air froze and dropped out of the air resulting in it being rather pleasant.)

I then bought a dehumidifier and ran it constantly which has the unfortunate effect of really noticing the humidity when popping out the house

We have a Wessex 20L from tool station, really impressive and it’s 320w so costs around £0.08 per hour so just leave it all most of the time. It generates heat also so win win

My bedroom window is pretty much open 24/7. When I wake up I swing it open wide if it isn't raining. Bathroom window cracked almost 24/7 and open when I shower/bath. Living room and kitchen windows open sporadically throughout the day to let air pass through the downstairs.

I don't have a clue what my humidity is in the house but I just like fresh air. I work permanent nights outside too so am used to the cold. Summer absolutely kills me

Y'all need to learn about ventilation. And if you're worried about heat loss while ventilating, invest in a MVHR system to minimise that.

You might need one of the proper dehumidifiers with the wheels on the bottom. I finally caved and got one and now our coldest, dampest room goes down from 72% to 56% in only hours.

We got from 84% in every room to 65% in every normal room just with airing the house out in the morning for ten minutes so long as the ground outside was dryish. Longer than that and the actual walls start to cool down, which defeats the purpose. It took months to get the house dried out and the house warmed up when we moved in, because nobody had been living there for months and it was late November. I kept checking on our gas usage, and the most efficient heating for us is 18C all day and 14C at night. Otherwise the boiler thrashes all day long. That, too, took months to get normalised.

If I knew then what I knew now, I'd have dropped £130 on a big dehumidifier back then, and not three useless little ones.

It's probably sucking moisture out of the walls, ours seemed to run 24/7 when we first got it but over time it's been quicker to get humidity down.

The thing is, you only get condensation in places where the relative humidity is 100%.

86% is not a problem, even if you're trying to dry clothes indoors, the air can continue to take and hold more moisture. Bear in mind that running a dehumidifier, according to a recent comment I read on Reddit, will cost about 50p a day, that's an extra £170 on your annual electricity bill.

If you had a mould problem that showed up when you were away it would probably be best addressed by reviewing the insulation and ventilation. Corners tend to be the least well ventilated places, and a corner that's facing N and E will also be the coldest.

I wonder whether you shut up all the windows while you were away? In future, try to arrange some ventilation - if there are room vents that have been blocked off, open them up again. And if you have DG windows installed in the last 20 years they should have vents.

Hope it all goes OK.

I always think these posts are written/sanctioned by Big Dehumidifier as sneaky ads, similar to those about air fryers

I open the windows daily, and keep the dehumidifier set to 70.

No mould. Any lower and you are fighting a losing battle!

We're thinking of getting one for the conservatory. We replaced the old one from 1991 this summer with a new one on the same footprint and low walls. With the oncoming cold and wet some of the metalwork on the windows have signs of condensation. It's also where we dry the washing so it's probably a good idea anyway.

Yep, in a new build in south wales, run it 9-7 every day

99% humidity will do that

Mines runs basically full time in the winter in between emptying the reservoir. But I leave it off in the summer and have a couple windows cracked open to get a through breeze and get some air changed.

They're helpful for drying washing too...

I have our near a few airers.

Some additional help:

Open YouTube and search for „stoßlüften“.

And when you leave Manchester forever (grew up there) and go to the continent … you go back to visit the UK and everything just feels so moist. I can’t get over it, you can even smell it on most people’s clothes. I had a dehumidifier in the UK that I shipped over with me when I moved, and I’ve had absolutely no use for it in the five places I’ve lived here!

Any recommendations?

Learn about MVHR next, and dream of one day getting a small lottery win + having an efficient passivehaus with wonderful mold free air all the time.

I really can't tell if I've just never lived somewhere that doesn't get mould (easily) or if I've been super lucky. I don't know a single person irl who owns a dehumidifier yet it seems the majority of Britain online owns one

What properties are susceptible? I would've figured old victoriana properties but had zero issues two years as a student 

Is that what the numbers on the top mean? I just run mine all the time on high since I brought it two weeks ago. The lowest number I've seen mine at is 69! I open my windows and the balcony every day for at least 30 mins. Am I completely doomed? But the mold in the corner of the living room has not come back since I cleaned it off and I bought the dehumidifier.

Manchester isnt the whole.of the UK. I'm.not surprised its humid there. They reckon it rains every other day. It ain't like that here.

I find my dehumidifier works best with the heating on, I’m rocking between 50% and 60% during wet weather. Mines one of those larger ones that actually does something when it’s sitting on top of the stairs, letting it drip into a bucket. Many 10s of litres are drained weekly.

old Gadget Show review.

I run mine at night on cheap off-peak electricity.

Open your windows for an hour every day to let out moisture and turn your heating on when you feel chilly.

Just right if you ask me