What indoor temp and relative humidity do you have on a day like today?

sudzs

I live in a small house that is damp. I had a PIV unit fitted a few months ago but this week is the first time there's been wet weather for any length of time so can't really say yet if it's helping with the indoor humidity. But I'm really just wondering what sort of readings are other people getting on a damp muggy day like today. Indoor temp here is 21 - 22 C and RH is 82-85%. Would that RH be normal for a day like today??

LambshankRedemption

Relatively new build, ground floor apartment.

Temp: 23.5c, RH 65%.

Tree

2000s semi-d, all the windows open most days in the "summer", usual hole in the wall air vents, 22ºC / 61% rh according to the thermometer there on my desk (upstairs, just came in). Kitchen is 21/78, utiliy is 22/76, living room 22/63, another upstairs room 23/62
For refernce, met éireann says 18.4/80

sudzs

https://www.boards.ie/discussion/comment/122466777#Comment_122466777

A bit drier than here so. It's practically the same temp and RH outside as it is in. That's with windows closed. I don't think the PIV is helping.

LambshankRedemption

https://www.boards.ie/discussion/comment/122466800#Comment_122466800

It could be helping. Ive lived in two houses in the same area as I am now and both had serious damp problems. The top layer of the duvet felt moist to the touch in the morning. I dont know what the RH of either house was, but I'd imagine it was close to 100%. I'd recommend getting a dehumidifier too for which ever room you spend time most in.

denismc

The PIV is going to do very little in this weather as the humidity is basically the same outside as it is inside. It's like living in the tropics in Ireland at the moment.

Our house at the moment is at 76%, that's with all the windows open.

You will see the benefit of the PIV in winter when the outside humidity is much lower.

Alun

23.8°C and 73% RH in the living room at the moment with the windows open.

Hippodrome Song Owl

21-22C. Downstairs is 77% humidity with the patio doors open to keep the cat happy. Upstairs is 60% because windows are mostly closed (a couple on ventilation setting) and there's a dehumidifier running full blast for the past 3 hours to make it more tolerable. I have a dehumidifier downstairs too but no point when the cat insists on the door open. I hate high humidity and it's a battle to keep it below 60% in summer. Hasn't been as bad this summer overall tbf.

I use this to decide whether or not to open the windows (needing to open door for the cat aside):

https://www.richard-stanton.com/humidity-calculator/

sudzs

https://www.boards.ie/discussion/comment/122466812#Comment_122466812

That's awful about the duvet, sounds like you're in a much drier spot now.

sudzs

https://www.boards.ie/discussion/comment/122466799#Comment_122466799

Even with the temp difference your place is still a bit drier than mine. This is an older place though, concrete floors on ground that gets waterlogged. The back garden develops a shallow lake after heavy rain!

sudzs

https://www.boards.ie/discussion/comment/122466865#Comment_122466865

How do you find the cost of running the dehumidifier? I might have to consider one. I hate feeling the high humidity too. Even at 21 C it just feels horrible. But yes, most of the Summer has been fine, nice and dry even if on the chilly side.

banie01

1980's semi, temp 22.2⁰ and 61% humidity. No active cooling but occasionally running a ran for the Mrs.

Hippodrome Song Owl

https://www.boards.ie/discussion/comment/122466963#Comment_122466963

I don't notice the cost tbh. I live alone in a 1990s 3-bed semi and I'm a low user of electricity overall - under 2000 units a year. No idea what the dehumidifier contributes though. It hasn't been on much this summer other than drying clothes. It was on a lot last summer. I don't need it much once the heat is on in winter. I generally stick it on once the humidity goes over 60%.

Lumen

High RH isn't so much of a problem in summer, because there are no cold surfaces in the building fabric for the vapour to condense on.

10-10-20

https://www.boards.ie/discussion/comment/122467028#Comment_122467028

Key statement. 👍️

Here's mine:

Those are completely natural RH levels - no cooking or biological interference in the house so far this week. ShellyHT1 is the main bedroom.

Lumen

https://www.boards.ie/discussion/comment/122467028#Comment_122467028

Just to expand on this a bit. The important thing is the dew point temperature.

So, taking the example from the OP:

Indoor temp here is 21 - 22 C and RH is 82-85%

If you plug those numbers into a dew point calculator you get a dew point of 17C.

So condensation will happen indoors if there's a 17C surface to condense on, which…there won't be in summer, until you open the fridge. But condensation in and of itself isn't much of a problem. Everyone has condensation in a bathroom during a shower, but it dries out afterwards so there's no mould risk - mould requires constant dampness.

Real problems are in winter. e.g. if you have indoor 70% RH at 18C, you only need a 12.4C surface for condensation, and that's easy to achieve if there's cold bridging, poor ventilation, and the outdoor temperature is low.

Ventilation will fix that (because warming up outdoor air drops the RH), but because cold bridging and poor insulation are often in the same building, people (owners, occupiers) tend to reduce ventilation to combat poor insulation, and then you get the bad combo of big temperature differences and high internal RH.

I think.

The Continental Op

Old Cottage with no dpc. Stays the almost the same humidity year round 75% RH temp currently 20°C

The degree symbol for anyone that wants it » ° «

sudzs

https://www.boards.ie/discussion/comment/122468846#Comment_122468846

I'm big on ventilation. I try to follow the German way of opening all the windows for 10 minutes every day, sometimes twice, even in the depths of winter. So I'm not sold on this PIV unit at all. Can't see how it will help in damp weather, won't it just suck in the damp air in the roof space into the house. I noticed when the rain started yesterday that the RH was going up where the air inlet is. Other rooms stayed drier and warmer for longer. I suppose it might help to clear the humid air out but I don't think it will be much better than my window opening.

sudzs

https://www.boards.ie/discussion/comment/122466865#Comment_122466865

Thanks for that RH calculator, I'm loving it!

brokenbad

1980's 4 bed bungalow. Humidity levels hover between 70-80% this time of year. Inside temp currently 21°

Have intermittent problems with mould on ceilings and mildew on clothes - particularly in bedrooms.

Started putting dessicant packs in the wardrobes to absorb moisture.

Open small sash windows every day, and at night - i leave them partially open.

Run a dehumidifier every night and it collects approx 4 litres of water over a 12 hour period.

When humidity levels are high, the bedroom and bathroom doors also expand slightly and get stuck.

sudzs

https://www.boards.ie/discussion/comment/122473397#Comment_122473397

That is high humidity. What about during a long dry spell, doesn't it come down then? Could you have a water leak somewhere? My place can be down around 45 - 50% when it's warm and it hasn't rained for ages.

brokenbad

https://www.boards.ie/discussion/comment/122477475#Comment_122477475

No leaks that i am aware of. The bedrooms are the only rooms that have the highest levels of humidity. There are also no wall vents in these rooms which doesn't help with natural ventilation.

drury..

https://www.boards.ie/discussion/comment/122477601#Comment_122477601

That's your problem

L1011

Currently 51.4% RH in a bedroom, that has laundry baskets with towels that would have been damp this morning in it too.

Single room MHRV fitted, has made an incredible difference to humidity.

ted1

currently 55% in the hall, house built in 84, 100m from the sea ( east coast) windows open.

Upstairs bedroom do get far higher humidity so use a dehumidifier during autumn and winter in the box bedrooom with 2 external Walls.

howsshenow

Lumen re earlier post with digital line chart recording of Humidity levels.. Could I please ask what kit you are using for this?

Thank you.

The Continental Op

Don't know what Lumen uses but I have airthings monitors because I wanted to check on Radon Gas.

This might give more of an idea https://automatedhome.com/reviews/review-airthings-wave-plus-smart-indoor-air-quality-monitor-radon-detector.html

Lumen

https://www.boards.ie/discussion/comment/122486585#Comment_122486585

That wasn't my chart 🙂

10-10-20

https://www.boards.ie/discussion/comment/122486585#Comment_122486585

It's Home Assistant connected to any of the temperature and humidity IOT sensors such as these Sonoff models:

https://www.domadoo.fr/en/heating-air-conditioning/7052-copy-of-sonoff-zigbee-temperature-humidity-sensor-with-support-snzb-02p.html

You can also attach Zigbee sensors to Ikea's IOT hub and generate very basic graphs too.