How do you keep humidity under 70% in the UK?

ProTofik

Alright so I have recently became a home owner. The house I bought was built in the 90s. It has brand new doors and windows installed by the previous owner in 2014, I insulated loft up to 300mm, blocked off fireplace (leaving a tiny vent as advised by the chimney sweep), and did few other things which really helped with heat retention. 

One problem I can't find a quick fix for right now is indoor humidity. When the house is at around 19-20C, RH indoor is constantly at around 70%. On a dry sunny day if I vent the house for 10 mins I can usually knock it down to around 60% for few hours, but if it is like it has been here for the past week or so (constant rain), opening doors and windows makes humidity worse.

My previous place was built in 2010s and had MHRV. Thanks to it the humidity there never exceeded 45-50% and I really do miss it. I will get MHRV installed here next summer but right now, I need to find a way to comfortably get through this winter.

Lidl seems to have those 10L dehumidifiers that draw around 200W per hour. Would that be able to decrease humidity to around 50% in a 10m2 room? If so, how long it would have to run to achieve it assuming the door is closed? Those are the questions I can't seem to find an answer to on google.

alanobrien

Our place is a 1970's build well insulated and double glazed but with 4 in the house the  RH does rise above 70 especially when its been raining non stop.    To reduce the RH to 60 or less we use two Ecoair DD1 desicant dehumidifiers one upstairs one downstairs and we run them with the doors open.   Works well for us even with washing drying in the kitchen over the winter period.  

gozaimasu

What do you use to measure your indoor humidity?

badmemory

Humidity of 70% does seem very high.  The only room in my house that gets that high is the bathroom after my son has had a 30 minute shower.  We have a dehumidifier to deal with that.  Even the room I run a tumble drier in doesn't get that high even without putting the "hose" out of the window.  Are you sure you don't have any damp issues?  Cooking with a gas cooker seems to put the humidity up higher though.

knightstyle

Just living in a house raises the humidity, washing, drying etc.  Ventilation is the answer.

daveyjp

Why do you need to keep hunidity below 70% in the UK?

My hygrometer is currently showing 92% outside, 72% inside, never worried me its above 70%.

ProTofik

gozaimasu said:

What do you use to measure your indoor humidity?

Small Xiaomi thermometers, on in every room and hall connected to home assistant.

daveyjp said:

Why do you need to keep hunidity below 70% in the UK?

My hygrometer is currently showing 92% outside, 72% inside, never worried me its above 70%.

To feel warmer, fresher, and not to have to wipe down windows every morning.

knightstyle said:

Just living in a house raises the humidity, washing, drying etc.  Ventilation is the answer.

I know I mentioned MHRV in my first post but after spending few hours yesterday reading on the topic, I think PIV is the answer to my problems. £350 and an hour or two to install.

Rosa_Damascena

ProTofik said:

gozaimasu said:

What do you use to measure your indoor humidity?

Small Xiaomi thermometers, on in every room and hall connected to home assistant.

daveyjp said:

Why do you need to keep hunidity below 70% in the UK?

My hygrometer is currently showing 92% outside, 72% inside, never worried me its above 70%.

To feel warmer, fresher, and not to have to wipe down windows every morning.

knightstyle said:

Just living in a house raises the humidity, washing, drying etc.  Ventilation is the answer.

I know I mentioned MHRV in my first post but after spending few hours yesterday reading on the topic, I think PIV is the answer to my problems. £350 and an hour or two to install.

Is it really necessary when you could open a window?

Hopingforthesimplelife

My family of 4 live in a 1870 build and have similar RH levels to you. Don’t really have a quick fix apart from the meaco Zambezi dehumidifier which does the job (but is quite costly to both buy and run with the current electricity rates I should imagine)

Hopingforthesimplelife

daveyjp said:

Why do you need to keep hunidity below 70% in the UK?

My hygrometer is currently showing 92% outside, 72% inside, never worried me its above 70%.

Mould grows at >70% rh.

https://www.oxford.gov.uk/info/20271/guidance_for_private_tenants/1129/preventing_damp_and_mould

FreeBear

ProTofik said:

gozaimasu said:

What do you use to measure your indoor humidity?

Small Xiaomi thermometers, on in every room and hall connected to home assistant.

A mix of cheap ebay sensors here (modbus & 433MHz). Humidity is in the 55-75% range depending on day & room.