How to reduce humidity inside the house (Ed.)

[Bobbyb89]

Really struggling with humidity levels in our house, trying to get a better understanding of it all. Keep reading to open windows, which we do but when humidity levels are 93 percent outside surely that will make the humidity levels worse in the house? If the house is sitting at 70?

 

[Wayners]

Our humidity is around 50. We don't open windows or the trickle vents.
We dry washing with dehumidifier in a room and run two small dehumidifiers in the evenings for a few hours.
This works for us but might not for you

 

[Deleted member 317777]

If your bathroom is full of steam etc what do you do ? Open the window.

Air exchange is important. Damp is mainly caused be lack of proper ventilation

 

[Wayners]

I've said before but our bathroom is at the centre of house so no window. Loft conversion above. This stops the condensation and mould forming as seems to dump on windows.
Dehumidifier stops that though now.

It's different solution for everyone it seems. Interesting subject though

 

[Deleted member 317777]

I've said before but our bathroom is at the centre of house so no window. Loft conversion above. This stops the condensation and mould forming as seems to dump on windows.
Dehumidifier stops that though now.

It's different solution for everyone it seems. Interesting subject though

An internal bathroom needs a proper fan. A dehumidifier is a last resort.

Negative pressure fan and a proper terminal

 

[noseall]

Really struggling with humidity levels in our house, trying to get a better understanding of it all. Keep reading to open windows, which we do but when humidity levels are 93 percent outside surely that will make the humidity levels worse in the house? If the house is sitting at 70?

Movement of air (air-flow) is important.

 

[StephenStephen]

Really struggling with humidity levels in our house, trying to get a better understanding of it all. Keep reading to open windows, which we do but when humidity levels are 93 percent outside surely that will make the humidity levels worse in the house? If the house is sitting at 70?

My understanding is that humidity levels are usually higher inside than outside - I found 'The Damp House' by Heatree a useful book to read.

 

[noseall]

It's different solution for everyone it seems. Interesting subject ththough

Correct. Highly idiosyncratic. You can have identical houses on the same street with wildly varying condensation issues.

 

[mattylad]

As I type my humidity level in my attic room is 69, it's often higher.
I do keep the velux vent open except on the coldest days/nights.

We open the bathroom window when we have a shower as we have no fan and keep the bathroom door closed afterwards.
We also have a large dehumidifier in the spare room (door open) going a lot to bring it down however it does not affect my attic room.

it has been suggested (by her) that the high level up here is partly due to the jungle of plants in my daughters attic room.

Hence I have had to invest in a lot of expensive airtight containers for my 3D filament to stop it absorbing all this moisture lol.

There was a little mold on the external wall in the spare room when my son lived in there and had his tower PC running most of the time next to the wall, since he moved out and we decorated it we have not had any and the dehumidifier seems to keep it away.

It's worse in the winter when drying cannot be done on the line outside, this I guess is the same in most houses apart from those that don't want the neighbours to see their knickers on the line

 

[noseall]

It's worse in the winter

because the walls are colder

 

[mattylad]

No, because in the winter we cannot use the washing line outside so all the drying is done inside

 

[noseall]

No, because in the winter we cannot use the washing line outside so all the drying is done inside

Winter habits aside - condensation related problems are much worse in the winter, simply due to the lower external temperatures. It's no secret.

 

[JohnD]

Really struggling with humidity levels in our house, trying to get a better understanding of it all. Keep reading to open windows, which we do but when humidity levels are 93 percent outside surely that will make the humidity levels worse in the house? If the house is sitting at 70?

Two points.

1) What you call "humidity level" is actually Relative Humidity. You meter is probably marked "RH"

This is the amount of water vapour, as a percentage of the amount that air AT THIS TEMPERATURE can hold. Hot air can hold more than cold. So a metre of hot air in the Sahara holds more water vapour than a metre of cold air in Manchester. But the air in Manchester feels damp, and has high RH, and the air in the Sahara feels dry, and has low RH. Houses in UK, especially in winter, are usually warmer than the outdoors air.

It therefore follows that if you replace some of the air inside your house, with air from outside, the outside air will contain less water, and the RH will drop when if warms up.

2) Houses do not create water. The activities inside the house put water into the air. In UK homes the biggest cause of damp, condensation and mould is water vapour from wet washing draped around or hung on radiators, followed by stesmy showers with insufficient extraction. Water vapour should he removed, quickly, at source. If you do not have a tumble drier, put wet washing in the bathroom and turn on the extractor fan. This will suck out the water vapour and prevent it drifting round the house.

Damp can also he caused by building defects such as spilling gutters, leaking plumbing and bridged DPCs, but these are less common and will be localised to the source.