Condensation Bedroom Windows

TheCyclingProgrammer · 6 October 2017 at 3:36PM

Your humidity levels taken this afternoon seem perfectly reasonable, presumably as a result of ventilation.

You need to keep an eye on it over several days to see if you can figure out what's causing the huge jump. Anything over 70% for a long period of time is cause for concern. The only time I ever see RH levels like that indoors are in late Summer when it's very humid outside (and so opening the windows doesn't help) but as it's only short term and during the day it doesn't cause any problems.

Also your indoor temperatures seem a bit high considering the outside temperature and your thermostat temperature. Do you have a TRV in the spare room? If so I'd turn it down a notch.

saintscouple · 6 October 2017 at 4:28PM

TheCyclingProgrammer wrote: »

Your humidity levels taken this afternoon seem perfectly reasonable, presumably as a result of ventilation.

You need to keep an eye on it over several days to see if you can figure out what's causing the huge jump. Anything over 70% for a long period of time is cause for concern. The only time I ever see RH levels like that indoors are in late Summer when it's very humid outside (and so opening the windows doesn't help) but as it's only short term and during the day it doesn't cause any problems.

Also your indoor temperatures seem a bit high considering the outside temperature and your thermostat temperature. Do you have a TRV in the spare room? If so I'd turn it down a notch.

Thank you, yes just checked and the TRV has set to the highest 5, i've bought this down to 3.
Do you think it would best to leave the windows ajar as they are now, or close them when we go to bed and just leave the ventilation to the trickle vents?
The wife sleep with a fan on, so leaving them slightly open wouldn't be problem.

Thank you again

saintscouple · 7 October 2017 at 11:18AM

Well woke to no condensation on the windows this morning, but it was warmer than the night before and also today we have had rain and it's very damp outside, still haven't changed anything from yesterday, windows still ajar. Temperature coming down in the bedroom, perhaps a result of turning the TRV down a couple of notches. Don't know if that's good or not, but the condensor tumble dryer will be going on in that room shortly.... having the window ajar should help with that though, we will see.
Perhaps it's worth noting the spare bedroom is west facing, the main bedroom, east.

shortcrust · 7 October 2017 at 11:39AM

I'm as obsessed as you about this stuff!:)

You might want to get one of these or similar:

https://www.amazon.co.uk/gp/product/B01NBVV2ZI/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

It shows dew point as well as RH%. Dew point doesn't change with temperature so you can tell if you're really getting rid of moisture as opposed to just heating the air. The readings update instantly rather than taking a few mins like the other meters you've got. This means it's helpful for identifying 'wet spots' as in a damp wall, leaking window - I think the readings are a bit odd in your spare bedroom and I wonder if water is getting in from somewhere.

I've got one of these dehumidifiers:

https://www.amazon.co.uk/gp/product/B0194MCV0G/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

It was a godsend a few days back when the air outside was damp and warm (i.e. no point opening windows!). I sometimes also use it in my bathroom for an hour after use if it's really cold outside and I don't want to open a window.

TheCyclingProgrammer · 7 October 2017 at 11:54AM

The readings in your master bedroom seem fine to me.

There’s definitely something odd going on in your spare bedroom that is causing the RH to get too high.

saintscouple · 7 October 2017 at 3:39PM

Thank you both, I'll keep the readings going for a week and then present them to the housing for them to make their investigations. Here's the latest with the tumble having been on a couple of hours....

I think the main bedroom is pretty constant, a little rise in temp and humidity from tumble being on just across the hall in the spare room is to be expected.
But the spare room's humidity levels have dropped with the tumble on....... wasn't expecting that.

TheCyclingProgrammer · 7 October 2017 at 6:19PM

The RH has dropped because the temperature has increased. You would need to work out the absolute humidity to see if it has changed.

saintscouple · 8 October 2017 at 5:06AM

shortcrust wrote: »

I'm as obsessed as you about this stuff!:)

You might want to get one of these or similar:

https://www.amazon.co.uk/gp/product/B01NBVV2ZI/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

It shows dew point as well as RH%. Dew point doesn't change with temperature so you can tell if you're really getting rid of moisture as opposed to just heating the air. The readings update instantly rather than taking a few mins like the other meters you've got. This means it's helpful for identifying 'wet spots' as in a damp wall, leaking window - I think the readings are a bit odd in your spare bedroom and I wonder if water is getting in from somewhere.

I've got one of these dehumidifiers:

https://www.amazon.co.uk/gp/product/B0194MCV0G/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

It was a godsend a few days back when the air outside was damp and warm (i.e. no point opening windows!). I sometimes also use it in my bathroom for an hour after use if it's really cold outside and I don't want to open a window.

I wake up at 4.30am to watch the F1 and part of my brain wakes up remember the many, many, many years ago when i went to technical college and had to calculate dew to work out the size of window needed for ventilation in a room...... now have to try and search that part of the brain that has the calculation formula.... or perhaps google is my friend.

Ahh indeed it is.... http://www.dpcalc.org/

I've started to look at what dehumidifiers are available preowned in my area, if i can find a cheap one that i can put on for a couple of hours in the morning / evening that may be a start and a help. I found if you buy a dehumidifier preowned, as long as it's working, you can sell for pretty much the same price you paid.

saintscouple · 8 October 2017 at 7:20AM

Just come across an article https://www.diynot.com/diy/threads/dehumidifier-or-piv-system.474384/ where it mentions a permanent solution by installing a PIV unit, something like this, https://www.amazon.co.uk/gp/product/B01MTP2LQW
Anyone read or considered one of these?
The bloke from housing mentioned this system when looking at the condensation issues last year.

tacpot12 · 8 October 2017 at 9:39AM

The PIV units are very effective, especially in properties that have trickle vents on the windows. The positive pressure moves damp air out of the whole property replacing it with dry air, whereas an extractor fan pulls the replacement air from rest of the property into the room it is fitted in. If this air is already damp, the damp room dries out more slowly.

I looked at fitting a PIV unit into a rental flat that was having a bit of a damp problem in the bathroom, but held off as the tenants were changing and I wanted to see if the tenants made a difference. I even looked at building my own PIV unit but cost of the parts was only a few pounds less that a Nuaire Flatmaster so I gave up on that idea.

Condensation Bedroom Windows

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