PIV unit in a 27sqm flat overkill?

hang3r

I have recently moved in to a small studio flat (27sqm including bathroom) with an open plan kitchen. Even though I haven't cooked or dried any clothes yet and I keep bathroom door closed, I've noticed every morning I wake up to both windows (the living room and kitchen one) completely soaked top to bottom with condensation. A couple of times I tried leaving the windows slightly ajar the whole day, which reduced the humidity by evening (to 60%), but by morning it woud be back (to about 85%).

The flat does have access to a loft, so I was considering installing a PIV unit (example link below) in the kitchen (marked red on the image). Is it overkill? Would I be able to hear it at night on the other end of the flat where my bed is (since no walls), or would the fridge in the kitchen drown out the noise? And, would it significantly reduce the temperature of the whole flat?

https://www.amazon.co.uk/Nuaire-Drimaster-Eco-LC-Control/dp/B07Q3616PK

As an alternative, I am considering getting a powerful dehumidifier that I can set on a timer to run for a few hours a day while I'm at work with a pump so I can drain directly to kitchen drain pipe and be basically maintenance free. However, the flat is small and would like to avoid moving it around every day, so it would need to sit underneath the breakfast bar in the kitchen (green in the image), and would be surrounded by the counter above it and walls on 3 sides (with some clearance, of course). Hence, I thought if I got something more powerful than I need, that should balance out the poor placement? For instance this 50l/day one:

https://www.amazon.co.uk/iOCHOW-50L-Electric-Compressor-Dehumidifier/dp/B0CFTMGWR7

QrizB

Are the windiws double-glazed (or better)? I would expect single-glazed windows to run with condensation at this time of year, and wiping them down was always part of my morning routine.

If they're double-glazed, you might have other problems.

hang3r

Double-glazed, wooden windows. The rubber seals on them look quite old and some are cracking or are loose.

The bathroom also has some mould on the tiling, so am also planning to install a more powerful fan as well there (again, perhaps one of those loft-mounted ones). Doesn't look like the flat was well looked after by the previous tenant.

Newbie_John

In my case the main source of humidity is bathroom, the air goes through the gaps or when the door is left open.
We do have fan, but it doesn't really do such a great job tbh.

We have a 12l Meaco dehumidifier which runs over night and it removes 95% of window moisture. It's fairly quiet and we're able to sleep with it - just sounds like a fan.

hang3r

Newbie_John said:

In my case the main source of humidity is bathroom, the air goes through the gaps or when the door is left open.
We do have fan, but it doesn't really do such a great job tbh.

We have a 12l Meaco dehumidifier which runs over night and it removes 95% of window moisture. It's fairly quiet and we're able to sleep with it - just sounds like a fan.

Interesting, my bathroom door does have quite large gaps, and currently the fan sounds like a helicopter, so possibly clogged up or close to dying, the other reason why I wanted to replace it.

GDB2222

People exhale around 250ml of water overnight. That’s enough to make the windows quite wet. 

There may be other sources of moisture in the flat, but don’t underestimate your own contribution! 

We sleep with the windows open, and the house is rather old and draughty, anyway. I think that we would need a dehumidifier otherwise.

Newbie_John

hang3r said:

Newbie_John said:

In my case the main source of humidity is bathroom, the air goes through the gaps or when the door is left open.
We do have fan, but it doesn't really do such a great job tbh.

We have a 12l Meaco dehumidifier which runs over night and it removes 95% of window moisture. It's fairly quiet and we're able to sleep with it - just sounds like a fan.

Interesting, my bathroom door does have quite large gaps, and currently the fan sounds like a helicopter, so possibly clogged up or close to dying, the other reason why I wanted to replace it.

My one is quiet, it does work OK - when I put sheet of TP flat it sucks it from my hand - but even so windows are every wet.
The dehumidifier gets up to 2l every day - as GDB says, multiple breaths add up + good insulation and double glazing .

No idea what could work here - leaving windows open sounds like heat waste which is way more costly than dehumidifier, stronger fan? 

Grenage

What temperature do you keep the flat?

Emmia

hang3r said:

Newbie_John said:

In my case the main source of humidity is bathroom, the air goes through the gaps or when the door is left open.
We do have fan, but it doesn't really do such a great job tbh.

We have a 12l Meaco dehumidifier which runs over night and it removes 95% of window moisture. It's fairly quiet and we're able to sleep with it - just sounds like a fan.

Interesting, my bathroom door does have quite large gaps, and currently the fan sounds like a helicopter, so possibly clogged up or close to dying, the other reason why I wanted to replace it.

If you replace your bathroom fan, get one with a humidistat which will turn the fan on if the moisture level goes over a certain point - I'd actually try this before a dehumidifier or the PIV.

This type of bathroom fan dealt with our damp / humidity problems better than our Meaco dehumidifier, will work without you needing to do anything and take up no room. (We have Vent Axia extractors which are very quiet)

Incidentally is the loft space demised to your flat? If it isn't you shouldn't be putting things up there like PIVs

ThisIsWeird

Hi Hang3r.
I would suggest that, yes, a PIR would be overkill here. In any case, you can crudely replicate what one does by leaving a decent extractor fan running in your bathroom, and you should fit one of these in any case.
Bro has just fitted a couple of 'Smart' extractors, which are fully controllable, near completely silent in main use, App controlled, and even responds to 'smells'. I'll get the model - they 'retail' at many £100s, but can be got around £150. *
Then look at your temp control. I presume you have heating at normal, comfy levels during 'living' times? And then what overnight and when you are out? I presumed turned down or even off? How well insulated is your flat - how quickly does it respond to a heat demand? What type of CH system is it?
How many of you are in the flat? I ask 'cos you'll need their general agreement for the following...
See how opening your windows during the day dramatically reduced your humid levels? Well, the exact same will happen overnight. And you can prove that in one single night; turn the heating right down, say to 10oC, before bedtime, open the kitchen window ajar, and your bedroom window to at least 'vent', but ideally an inch open. Make sure you and your bed are warm - toggie duvet, and an overnight leccy blanket if you really must.
Wake up to a very chilly - but almost certainly bone dry - flat. So, there's your answer, and it costs nothing.
Of course, have your heating set to come on before you actually wake up so you have a welcoming flat, then first thing close the windows whilst you get ready for the day. When you go out for reasonable periods - a few hours, say to work - then heating right down again to a level it's easy to recover from - 10o or a bit more - and 'vent' the windows again. Once home, windows closed (or perhaps to 'trickle'), and heating to comfy level.
Just bear in mind that whenever you have the flat heated for 'living' in, Ie 18+o and with windows closed, the humidity levels will be climbing rapidly, with a large amount of water being held in that warm air, so you'll need to vent it away if it ain't going to end on your windows when the heating is off.

Two ways - ventilate it away as described above, or buy a dehumidifier. But who the heck wants a dehumidifier if it ain't actually needed?

* Vent-Axia PureAir Sense Extractor Fan with Odour Sensor 479460

moneysaver1978

ThisIsWeird said:

Hi Hang3r.
I would suggest that, yes, a PIR would be overkill here. In any case, you can crudely replicate what one does by leaving a decent extractor fan running in your bathroom, and you should fit one of these in any case.
Bro has just fitted a couple of 'Smart' extractors, which are fully controllable, near completely silent in main use, App controlled, and even responds to 'smells'. I'll get the model - they 'retail' at many £100s, but can be got around £150. *
Then look at your temp control. I presume you have heating at normal, comfy levels during 'living' times? And then what overnight and when you are out? I presumed turned down or even off? How well insulated is your flat - how quickly does it respond to a heat demand? What type of CH system is it?
How many of you are in the flat? I ask 'cos you'll need their general agreement for the following...
See how opening your windows during the day dramatically reduced your humid levels? Well, the exact same will happen overnight. And you can prove that in one single night; turn the heating right down, say to 10oC, before bedtime, open the kitchen window ajar, and your bedroom window to at least 'vent', but ideally an inch open. Make sure you and your bed are warm - toggie duvet, and an overnight leccy blanket if you really must.
Wake up to a very chilly - but almost certainly bone dry - flat. So, there's your answer, and it costs nothing.
Of course, have your heating set to come on before you actually wake up so you have a welcoming flat, then first thing close the windows whilst you get ready for the day. When you go out for reasonable periods - a few hours, say to work - then heating right down again to a level it's easy to recover from - 10o or a bit more - and 'vent' the windows again. Once home, windows closed (or perhaps to 'trickle'), and heating to comfy level.
Just bear in mind that whenever you have the flat heated for 'living' in, Ie 18+o and with windows closed, the humidity levels will be climbing rapidly, with a large amount of water being held in that warm air, so you'll need to vent it away if it ain't going to end on your windows when the heating is off.

Two ways - ventilate it away as described above, or buy a dehumidifier. But who the heck wants a dehumidifier if it ain't actually needed?

* Vent-Axia PureAir Sense Extractor Fan with Odour Sensor 479460

Sorry to jump in but that smart fan sounds great! I wonder if they work with Alexa/Siri...