condensation, insulation and trickle vents

[savedave]

Hi all.

This is my first time posting. I am trying to work out the right balance between insulation and ventilation.

I recently bought a flat. It's a relative new build, about 8 years old, with double glazed timber windows and balcony doors. The doors were petty draughty; they may have been fitted wrong or were too short, so I have spent a while fitting various types of draught excluder. I'm keen to reduce my winter fuel bills and keep the place warm.

Broadly speaking I have been relatively successful. But now I notice I get some condensation on the windows, about 4cm, along the bottom of the windows, and some on the bottom lip of the door's threshold (forgive me if I use the wrong terminology there).

I have trickle vents which are currently closed, because I cannot understand why I would have them open to lose heat in the winter, after spending ages dealing with draughts. On the other hand I don't want my timber windows to rot.

So, what is the right balance between insulation and ventilation. How much draught or condensation should I live with, or is there a way to eliminate both?

Thanks kindly,

Dave

 

[freddiemercurystwin]

No there is no way eliminate both, open those vents up, at his time of year they should be open. The only gauranteed way to eliminate condensation is to have air conditioning or open your windows more. So if you want to minimise condensation you have to maximise ventilation. Sorry but these are two ends of the spectrum that do not gel well in modern dwellings and you have to compromise somewhere.

 

[savedave]

Thanks for your reply. So your opinion is that it's better to lose heat than to have condensation, is that right? And the vents should be open 24/7/365? Is this the general consensus, and would you mind explaining why? Sorry if this is basic stuff, I am a first time property owner!

I've always been obsessed with keeping my home warm, as I really feel the cold, and the financial pinch. The thought of losing heat that I am paying for bothers me!

Is there ever a time to close the vents?

To clarify, the condensation on its own doesn't bother me much as it just gathers on a small area of the windows and doors. It's only if it may cause damage to the paint, wood, walls etc that it would worry me. Could it?

Thanks again

 

[savedave]

To add to this, I have had the vents open now for a few hours, and I wiped off the condensation bit it has reformed anyway, the same amount roughly. I suppose I do have laundry drying and it is minus two degrees outside, but shouldn't the open vents be enough to prevent the condensation?

Maybe I am being too impatient!

 

[Gazman16]

I started compiling some information on ventilation a few years ago on an old now pretty much dead forum:

http://www.double-glazing-forum.com/topics.aspx?ID=34

There is some good information on this link and links to some more sites.

I hope posting external links is allowed here

 

[JohnD]

I do have laundry drying and it is minus two degrees outside

you mean you're adding a couple of litres of water to the air, and you're surprised you get condensation on a cold surface?

What do you suppose is the main cause of condensation, damp and mould in UK homes?

//www.diynot.com/wiki/building:condensation_in_houses

 

[savedave]

thanks for these replies and links - I have had a read.

So I understand the problem a lot better but still am not sure what I am meant to do, in terms of achieving the balance of heating efficiency with not allowing condensation to damage my property.

I have no choice but to dry my laundry indoors - I dont have a tumble drier and have no outside space.

I have trickle vents - if they are critical, why can they be closed at all? Or is there a time to open them and a time to close them (for example, open them always in summer and in winter only when a room is not being used?)

I dont think I have an autovent or any other type of formal ventilation, except for extractor fans in the kitchen and bathroom (in the bathroom it is automatic).

So all in all, what is the best strategy? Is seeing a small amount of condensation ok, or is any condensation a problem? when should you open and close trickle valves? And what should be done if the trickle valves are open and you still get a small amount of condensation?

Thanks loads - I find this confusing so your advice is really helpful

dave

 

[JohnD]

If you drape wet washing around your home, it will release a lot of water into the air, so you will have to ventilate a lot to get rid of it.

If your bathroom has an effective extractor fan, you can hang the washing over the bath, perhaps on a roll-away line, and leave the fan running, with the door and window shut, until it is dry.

Even without added water, you should leave your trickle vents open at all times.

 

[savedave]

Thanks - that's an idea, re the laundy, though leaving the light and fan on in the bathroom all night feels wasteful.

So are you really never supposed to close trickle vents? Why are they closeable then?

 

[freddiemercurystwin]

You can close them whenever it is appropriate, all properties are different, my missus has washing draped over a clothes horse 24/7, its a modern house we have the vents all closed off yet we don't get any condensation anywhere. My last house was modern too, as a bachelor I did washing once a week and dried it on a clothes horse, had all the vents open and had a bit of condensation on the windows/reveals. Its really very unpredictable. You put up with condensation or change your living habits.

 

[JohnD]

a typical bathroom extractor fan will run for 50 hours on 14p worth of electricity.

A typical energy saving bulb, about the same.

 

[savedave]

Thanks everyone.

While I read in the various links the benefits of fresh air, and that severe condensation can cause serious problems in the materials of the house, is the small amount I experience (a few cm at the bottom of each window, and on the lip at the bottom of the doorframe/threshold) an actual problem?

thanks again for all your advice and comments