Condensation and mould on windows... Vents open?

LoveABargain66

I seem to have an issue with condensation on my windows and mould growing around them as well. This is happening on every single window and also on the balcony door. All the trickle vents are open and I can feel cool air coming through them (I thought they were supposed to prevent this from happening but apparently not)

I'm not running the heating as it's not really cold enough yet. It's 2'c outside at the moment and 15'5'c inside (plus condensation is caused by warm air hitting something cold so I'd imagine that having the heating on will actually make the air warmer and make the situation worse... Correct me if I'm wrong though as this could even be the cause, I'm just guessing here!)

It's also a new build property finished in around April this year. I've read that new build properties usually suffer with mould and such for 12 months or so due to the amount of moisture that gets into them whilst they're being built (no roof, windows etc) BUT my neighbours aren't having this issue, just me!

I've read about how dehumidifiers can help, but I'd have to buy one for every room and at £40 just for a small ones that's gonna be very expensive (not too mention the electricity cost to run them!)

Does anyone have any advice or recommendations? Maybe something I'm not doing that I should be or vice versa? Thanks in advance.

This is what one of the windows looks like with condensation all around the trickle vent, it'll be all over the glass in the morning! 

FreeBear

LoveABargain66 said: I'm not running the heating as it's not really cold enough yet. It's 2'c outside at the moment and 15'5'c inside (plus condensation is caused by warm air hitting something cold so I'd imagine that having the heating on will actually make the air warmer and make the situation worse... Correct me if I'm wrong though as this could even be the cause, I'm just guessing here!)

Try turning the heating on and getting the place up to 19°C or even 20°C. Then pick up a dehumidifier (second hand one from Facebook/ebay/gumtree) such as an Ebac and place it somewhere central in the house. Landing or hallway for example. Get some thick thermal curtains to hang over the windows and pull them in an evening.

Yes, a new build will take a while to dry out thoroughly, But if the walls & windows are cold to start with, any moisture will condense out - Get the temperature up, let the dehumidifier suck up the worst of the moisture during the day, and the problem should clear up. Those little £40 dehumidifiers are OK for small spaces such as caravans & campers, but don't really have the capacity for a larger room (I had one myself).

badmemory

At those temps I suspect even your carpets will feel damp in a new build.  You could even just move the dehumidifier around, as in a couple of hours here a couple of hours there.  This is probably against most normal advice but if you get a decent dehumidifier, turn up the heating & close the vents then it should soon get sorted & you can go back to open vents & the draft they cause.  Can you tell I hate drafts?

Doozergirl

badmemory said:

At those temps I suspect even your carpets will feel damp in a new build.  You could even just move the dehumidifier around, as in a couple of hours here a couple of hours there.  This is probably against most normal advice but if you get a decent dehumidifier, turn up the heating & close the vents then it should soon get sorted & you can go back to open vents & the draft they cause.  Can you tell I hate drafts?

Why close the vents?  They'll still do their job with a dehumidifier running.  

It's a new build house, the air quality will
be dreadful with the vents closed, plus the owner is constantly producing more moisture by living in it, so you're not saving the dehumidifier a job by closing vents, you're just reducing air movement.  There is a requirement under building control for new build houses to not be draughty, it's actually measured before the house can be signed off.  What they do need is ventilation, not just to prevent mould, but to provide fresh air for the health of the inhabitants.  No trickle vent should feel like a draught in a new build. 

When do I get to stop constantly sticking up for trickle vents?! 

tacpot12

Warmer air hold more water vapour, so you get less condensation, plus warmer air means warmer surfaces so less condensation again. 15.5C inside is too cold and is promoting the condensation. 

I'm another fan of trickle vents and have fitted them when they were not present. 

If the dehumidifier doesn't stop the condensation after a year, I'd suggest you look a positive input ventilation systems (PIV). These systems move damp air from the house to the outside, via the trickle vents. It's like having a small extractor fan in every room. They are not that expensive and can be fitted by an electrician.  

Bendy_House

LoveABargain66 said:

I seem to have an issue with condensation on my windows and mould growing around them as well. This is happening on every single window and also on the balcony door. All the trickle vents are open and I can feel cool air coming through them (I thought they were supposed to prevent this from happening but apparently not)

I'm not running the heating as it's not really cold enough yet. It's 2'c outside at the moment and 15'5'c inside (plus condensation is caused by warm air hitting something cold so I'd imagine that having the heating on will actually make the air warmer and make the situation worse... Correct me if I'm wrong though as this could even be the cause, I'm just guessing here!)

It's also a new build property finished in around April this year. I've read that new build properties usually suffer with mould and such for 12 months or so due to the amount of moisture that gets into them whilst they're being built (no roof, windows etc) BUT my neighbours aren't having this issue, just me!

I've read about how dehumidifiers can help, but I'd have to buy one for every room and at £40 just for a small ones that's gonna be very expensive (not too mention the electricity cost to run them!)

Does anyone have any advice or recommendations? Maybe something I'm not doing that I should be or vice versa? Thanks in advance.

This is what one of the windows looks like with condensation all around the trickle vent, it'll be all over the glass in the morning! 

Good chance that much/some of this is down to what you suspect - the house is still effectively drying out from its build stage.

You say that none of your neighbours are suffering from this issue, so the simple Q is - what are they doing differently?! I suspect most of them have had the heating on, as ~16oC is quite chilly. Most folk want ~20oC in living areas, and ~18oC elsewhere.

Why is the condensation forming on the trickle vents and windows? Because that's the coldest parts of your house. Yes, the vents are doing their job - allowing a trickle of through ventilation - but that also makes the actual vent the coldest single item in your house other than your fridge and your mum-in-law's heart (oops, let slip...)

Why are you having cond when your neighbs are not? Because keeping cond at bay is a combination of temp and vent. Even if you have a similar amount of internal humidity being created as your neighbs (fabric of house, washing, cooking, breathing, etc), your house is colder, so the air cannot hold as much of that moisture in suspension, so more of it is released and condenses out on the coldest surfaces.

You solve this by either raising the temp a bit, or by increasing the ventilation even further. Possibly a comb of both.

~15oC, eh?! You like it cold! Ok, then, pal - turn your heating off all the way, and open a few windows ajar for a few hours. What will you have? A hoosie at around 8oC - brrrrr - that'll be bone dry.

So, if you really must have the heating as low at 16oC, then you need to vent away the resulting extra condensation too. It's a balance.

Hopefully this is a temp situation, and it will improve - over next Summer should certainly sort it.

You also need to check your living style compared to your neighbs - are you doing anything to create more moisture than them? Not extracting shower/cooking steam, airing damp clothes indoors, stuff like that?

twopenny

A house I'd lived in for years I tried to save money by closing up a couple of rooms without heating.
To my horror I found the oak door knobs and books were mouldy.
I put the heating on all day at around 15/16. It was economical as the boiler seldom kicked in. No mould. Condensation only early morning in bedroom and living room because the windows were behind thermal curtains so no heat reaching the glass.

koalakoala

Your house is way too cold. You'll ruin the structure of it.
i would guess your neighbours all have heating on.

valerie77

A dehumidifier is probably your best solution, I've managed with one while I've been trying to replace my old windows

GDB2222

I’d suggest opening the windows, to give the place a good airing. 

aoleks

let the place heat up properly, 15 degrees is not a normal temperature for a house. a house is meant to be warm and cosy.

open the windows during the day, for at least several days, to allow the place to ventilate, that will take the humidity out.

keep the heating on at 19 degrees at night, 21 degrees during the day. next to the trickle vent, crack the smallest window in each room a bit, to allow more air to circulate.

use a dehumidifier for a few weeks, until you're back in line and enjoy the flat. but not at 15 degrees, that's madness...