Condensation & dehumidifier questions

Apodemus

Devongardener said:

I use a Karcher window vac for condensation on windows, much quicker and cheaper than waiting for a dehumidifier to do the job.  I also use it in the shower cubicle, including the surrounding tiles and base, and as much of the rest of the bathroom surfaces I can reach.   

I’d say try to spend less time showering, 15 minutes is a lot!

I'd be wary of assessing household condensation only by what is on the windows.  Sure, you can remove the water from the windows with the Karcher, but that doesn't do much for the overall humidity - apart, perhaps from letting the windows act as an inefficient dehumidifier.  You are simply removing one of the visible signs of the humidity.  All the rest of the household fabric is still exposed to the humidity that was sufficient to allow the condensation to form on the windows.  A dehumidifier will address the problem, not just mask one symptom.

ss2020jd

I am monitoring an intermittent problem with condensation on some windows on the coolest part of the house. 

After reading lots of articles and threads I have tried a variety of things (detailed below) and at the moment have had no condensation, although obviously it’s been so mild that I’m not sure if it’s that, or anything I have done.

As @Apodemus says it’s not just the condensation on the windows that needs addressing its worth knowing the humidity as it could cause further problems if it remains high. 

I got some small quite reasonable hygrometer/humidity meters which have been invaluable. The readings in the bedroom hover around 60 which is at the high level. In the mornings after sleeping and breathing that increases to 64. Before the monitors I used to open the windows every morning and tried sleeping with them cracked open at night but it didn’t seem to improve much. I then read that sleeping with the bedroom door ajar and curtains open can help as well so have been doing that recently.
I run the dehumidifier in the bedroom (with the windows closed) for between half an hour to an hour after I get up until it gets below 60.
 I still open the windows when it’s dry, for ventilation, but sometimes it makes the humidity rise so I just monitor that. 

The heating is not on at night and on and off intermittently during day, trying not to drop below 17.5. 

I need to see what happens when the cold snap hits as I’m sure it will reappear then. 

Other more clever scientific people talk about dew points and temperatures but I haven’t quite mastered that yet.

Apodemus

ss2020jd said:

I need to see what happens when the cold snap hits as I’m sure it will reappear then. 

You might be surprised.  While a cold snap means a bigger difference between indoor and outdoor temps, it also tends (in UK) to mean drier outside air.  So while you might get condensation forming on your windows at a lower indoor humidity level than before, the opportunities for alleviating this by opening a window might increase.  

In our house, the worst period of the year for household humidity is the late summer, when the outside ambient air is warm and damp.  With no heating on in the house, it is difficult to do anything to bring down the humidity and that is when the doors swell and it is most difficult to fully dry the bathroom after a shower.  In contrast, during winter, with central heating and woodburner running, we are not only heating the property, but taking huge quantities of damp air out through the CH and woodburner flues.   

Devongardener

Apodemus said:

Devongardener said:

I use a Karcher window vac for condensation on windows, much quicker and cheaper than waiting for a dehumidifier to do the job.  I also use it in the shower cubicle, including the surrounding tiles and base, and as much of the rest of the bathroom surfaces I can reach.   

I’d say try to spend less time showering, 15 minutes is a lot!

I'd be wary of assessing household condensation only by what is on the windows.  Sure, you can remove the water from the windows with the Karcher, but that doesn't do much for the overall humidity - apart, perhaps from letting the windows act as an inefficient dehumidifier.  You are simply removing one of the visible signs of the humidity.  All the rest of the household fabric is still exposed to the humidity that was sufficient to allow the condensation to form on the windows.  A dehumidifier will address the problem, not just mask one symptom.

I agree,  I meant this as a quick fix for the bathroom condensation problem until the OP can get an extractor fan fitted. Just using the vac in the shower and tiles areas collects a good pint of water which would otherwise add to the air moisture in the house.

shiraz99

Apodemus said:

ss2020jd said:

I need to see what happens when the cold snap hits as I’m sure it will reappear then. 

You might be surprised.  While a cold snap means a bigger difference between indoor and outdoor temps, it also tends (in UK) to mean drier outside air.  So while you might get condensation forming on your windows at a lower indoor humidity level than before, the opportunities for alleviating this by opening a window might increase.  

In our house, the worst period of the year for household humidity is the late summer, when the outside ambient air is warm and damp.  With no heating on in the house, it is difficult to do anything to bring down the humidity and that is when the doors swell and it is most difficult to fully dry the bathroom after a shower.  In contrast, during winter, with central heating and woodburner running, we are not only heating the property, but taking huge quantities of damp air out through the CH and woodburner flues.   

This is true. Cold snaps are usually brought about during periods of High Pressure so the outside moisture content will be less, however if you keep all your windows closed then clearly RH in the house is going to increase and end up condensing on the now cold surfaces of the windows etc.

IM

Apologies for piggy-backing on this thread, rather than starting my own - but I've got a dehumidifier question too...

We have an upstairs utility room with washing machine and (vented) tumble dryer. 

We have an extractor fan which we always turn on whenever one of the machines is running.

However, when the weather gets a bit cold and damp, we always have a visible patch of discolouration on the external wall.

I'm not overly concerned about it, as I'm reasonably confident it's a legacy issue/a residual level of dampness within the plaster.

(We've replaced the guttering outside, and the house was re-pointed a couple of years ago).

At some point, when I run out of other things to spend my time and money on, I'll strip the plaster and whack some nice fresh stuff up.

Notwithstanding that, and with Black Friday coming up, I was thinking of a dehumidifier - but am frankly bamboozled at the options.

We've previously had one of those tiny ones and that was as much use as a fart in a space-suit - but at the same time I don't want to end up with something too big, powerful (and energy consuming) for the room*.

*It's approx 2 meters x 2 meters.

All recommendations gratefully received. 

BUFF

desiccants tend to be cheaper to buy, work better at cooler temps but cost more to run (perhaps 2x) than compressor dehumidifiers. I would suggest that you consider the temperature where you intend to use it & for how long at a time  & choose type accordingly. You can then narrow down to make/model.

IM

BUFF said:

desiccants tend to be cheaper to buy, work better at cooler temps but cost more to run (perhaps 2x) than compressor dehumidifiers. I would suggest that you consider the temperature where you intend to use it & for how long at a time  & choose type accordingly. You can then narrow down to make/model.

The room is unheated, so all it will get is the ambient heat from the rest of the house, plus whatever the washing machine/tumble dryer.

In terms of running time, I thought you ran them all the time at a low level?

shiraz99

When you run the the tumble dryer how close is it to the external wall? I have one in my kitchen and used to have issues with mould on the back wall after prolonged use and have found pulling the machine out away from the wall a bit both during and after use stops the condensation on the wall.

shiraz99

IM said:

BUFF said:

desiccants tend to be cheaper to buy, work better at cooler temps but cost more to run (perhaps 2x) than compressor dehumidifiers. I would suggest that you consider the temperature where you intend to use it & for how long at a time  & choose type accordingly. You can then narrow down to make/model.

The room is unheated, so all it will get is the ambient heat from the rest of the house, plus whatever the washing machine/tumble dryer.

In terms of running time, I thought you ran them all the time at a low level?

It's worth getting some cheap room thermometer/hygrometer to check the temperature and RH in that room. If the ambient temp is over 16 degrees I's stick with a compressor dehumidifier, if the temp drops quite low in there get a desiccant model but, as mentioned they are more expensive to run in comparison.

https://www.amazon.co.uk/ThermoPro-TP50-Digital-Thermometer-Temperature/dp/B01H1R0K68/ref=sr_1_6

or the ones I got:

https://www.amazon.co.uk/gp/product/B08DJ6M3HV/ref=ppx_yo_dt_b_asin_image_o02_s00