Inside humidity

tony3619

Hello, 

So I've recently been measuring the humidity in my house and over the last few days it ranges between 65%-73%

I've never had signs of mould or the smell of damp etc just the odd bit of condensation on one or two windows. 

It's a newish build built in 2017 and I'm assuming the readings are high due to ventilation. It's a strange set up as the living room and first floor bedroom dont have windows, just balcony doors that have trickle vents. 

In my stupidity I rarely open the doors and the trickle vents are normally closed so I guessing the readings are high because of this. 

I've since opened the vents and plan to open the doors every day for 10 mins to allow ventilation. This hasn't made a difference to the readings which currently sit at 67%. How long should I expect until the reading should drop and stay in the 55-65 range? 

rob7475

What is the temperature in the house?

I think outdoor humidity is only just starting to drop. My house is usually around 21 degrees and the inside humidity has been struggling to get below 60% for a while up until the last few days. It now drops to around 50% when the heating is on. We don't have any trickle vents but do have PIV running to stop condensation.

tony3619

rob7475 said:

What is the temperature in the house?

I think outdoor humidity is only just starting to drop. My house is usually around 21 degrees and the inside humidity has been struggling to get below 60% for a while up until the last few days. It now drops to around 50% when the heating is on. We don't have any trickle vents but do have PIV running to stop condensation.

Most of the day the temp is 16-18c with a couple hours of heating just to take the edge off. 

I typed the outdoor humidity and temp into one of those humidity calculators and it says based on this info humidity indoors should be around 62% so I'm assuming factoring in breathing, washing , cooking etc 68-70% is about right for the current climate? (UK obviously)

shiraz99

tony3619 said:

Hello, 

So I've recently been measuring the humidity in my house and over the last few days it ranges between 65%-73%

I've never had signs of mould or the smell of damp etc just the odd bit of condensation on one or two windows. 

It's a newish build built in 2017 and I'm assuming the readings are high due to ventilation. It's a strange set up as the living room and first floor bedroom dont have windows, just balcony doors that have trickle vents. 

In my stupidity I rarely open the doors and the trickle vents are normally closed so I guessing the readings are high because of this. 

I've since opened the vents and plan to open the doors every day for 10 mins to allow ventilation. This hasn't made a difference to the readings which currently sit at 67%. How long should I expect until the reading should drop and stay in the 55-65 range? 

Although the ideal RH range is between 40% and 60% I wouldn't say your readings of 65%-73% is that unusual given the current weather conditions and certainly wouldn't lead to big mould problems in itself. If you're regularly getting into the 80s and above then you should think about taking remedial action. You might consider a dehumidifier to keep it under 60% but good ventilation is key.

FreeBear

Indoor humidity here is currently ranging from 56% in the lounge to 68% in the box room (temperature is around 18°C). I would take the readings with a little bit of salt as the sensors have not been calibrated.

tony3619

So Ive been monitoring the readings for a few months now and during the cold spell last  month the RH would go down to 60%. 

Over the last few days where the temperature has gone Into double digits and we have had some rain the readings again are between 65-73% upstairs and 60-65% downstairs. I get a little condensation at the bottom of the windows in the morning but only a few drops. 

No matter how much I air the house or leave the heating on it never goes below 60%

Apodemus

tony3619 said:

No matter how much I air the house or leave the heating on it never goes below 60%

Where in the country are you?  Most of the UK has a very humid ambient environment, so you are expecting a lot of your house to try and keep RH levels at 60% or below!

tony3619

Apodemus said:

tony3619 said:

No matter how much I air the house or leave the heating on it never goes below 60%

Where in the country are you?  Most of the UK has a very humid ambient environment, so you are expecting a lot of your house to try and keep RH levels at 60% or below!

I am in Reading. So near the center of South England. So you would expect 60-70% in the current conditions?

Apodemus

tony3619 said:

Apodemus said:

tony3619 said:

No matter how much I air the house or leave the heating on it never goes below 60%

Where in the country are you?  Most of the UK has a very humid ambient environment, so you are expecting a lot of your house to try and keep RH levels at 60% or below!

I am in Reading. So near the center of South England. So you would expect 60-70% in the current conditions?

Well at the moment, the weather stations in Reading are all showing RH figures in the high 70s, so if you are airing the house at all, that is what is coming into the building.  How much that figure falls within the building will depend on a number of variables, but, personally, I wouldn't be losing any sleep at the figures you are quoting. 

_Sam_

According to Metoffice the humidity in Reading currently between 80 and 90%: https://www.metoffice.gov.uk/weather/forecast/gcpk9yegm#?date=2023-01-11

I read the explanations several times, but just can't get my head around the different humidity calculations

If you click on "i" next to humidity row on the table, it defines the readings as "humidity is the amount of water vapor in the air". This doesn't sound like RH?

Anyway here in the UK our climate tends to be more humid than not. I therefore think dehumidifier is a really useful appliance if you would like to maintain humidity around 40-50% in the house.

tony3619

_Sam_ said:

According to Metoffice the humidity in Reading currently between 80 and 90%: https://www.metoffice.gov.uk/weather/forecast/gcpk9yegm#?date=2023-01-11

I read the explanations several times, but just can't get my head around the different humidity calculations

If you click on "i" next to humidity row on the table, it defines the readings as "humidity is the amount of water vapor in the air". This doesn't sound like RH?

Anyway here in the UK our climate tends to be more humid than not. I therefore think dehumidifier is a really useful appliance if you would like to maintain humidity around 40-50% in the house.

My understanding is that if humidity outside is 80-90% at 8 degrees then opening windows will allow the colder air in. If this air is increased in temperature it can hold more moisture bring RH down.