Talk to me about condensation

[HeyMacWey]

Since autumn has appeared overnight I woke up this morning to find condensation on all the windows.

How can I minimise it?

Central heating is not yet on. House is double glazed bar two windows and generally warm in the mornings.

Have a woodburner and the last few days have been putting it on about 2ish and then putting load of coal on at about 5pm so it simmers gently all evening and ensures that it's warm when dh gets in about 11ish.

Today I've kept the upstairs windows open a few cm to keep air flowing to see if that makes a difference.

Should I keep them open all night?

Clothes have been line dried and then finished off on an airer in the bathroom with the extractor on (door closed).

I've been squeegeeing the water off first thing and then noticed condensation building up on the unglazed windows when it gets dark.

Should I put the central heating on for an hour or would that not make a difference?

Any tips most welcome

Thanks I'll try that! Where the mould is worst in my bedroom I never have damp washing . I do have a washer dryer but for some reason the dryer has stopped working and while the washing machine part is still working I'm not going to change it! Plus the cost! I'll look into building guarantee though as it shouldn't be this bad! It was like it in the summer too and there wasn't the condensation then!

Go out and buy a condenser dryer , open window after shower or bathing

Never mind all the kafuffall just do it. Never in the history of this pensioner have so many condensation droplets been exterminated.

Roneik I wish I could open windows I don't have any! And I don't have the money to buy a dryer I'm a single mum. I do think my flat should have been built with windows and proper ventilation

Sorry , I am staggered no ventilation or windows

What about a second hand dryer? Anyway I am sorry

Hi PJ

We have a Worcester Bosch boiler installed last year, with British Gas Hive active controls. Thermostat is in the hall in the coldest part of the house.

The house runs at 16 overnight and 20 during the day as we have a small baby.

Are there any downsides to using a dehumidifier? The amount of condensation on our double glazed wooden windows seems to increase each winter so I am now reading up to find the best solution. I live in a barn conversion built onto the ground and I swear damp comes up from the ground! No mould anywhere though. There are lots of wooden beams (and old bricks!) and just wanted to check that we'd not damage these by drying out the air?

I do open upstairs windows after a shower and leave open most of the day everyday. Too cold to have them open at night now and the condensation on the windows upstairs this morning was awful.

I do dry washing in the house downstairs on a Molly Maid type airer. This has lots of wet washing on it each day although I use the tumble dryer for bedding & towels.

We have extractors in the bathrooms but I don't think they vent outside - I think they vent into the roof space (maybe wrong about that).

Thinking best bet is to buy a dehumidifier (as an investment) and use around the house to reduce levels initially and then keep it in the laundry room to suck up water from wet washing. Or should we have it upstairs by the bedroom?

When we go away (and therefore windows all closed for a few days) I can smell moisture as soon as I come in the front door. It reminds me of the smell of walls soaked with warm water before scraping off wallpaper when my parents were decorating! That's not caused by wet washing though as it's when we have been away.

Fantastic thread!

We have problems in DD2's room - we are in a bungalow and are out all day, so flinging the windows open is not always practical. DD1's is almost as bad.

The room has two external walls and a very large window - one of the walls gets horrendously cold, wet and mouldy, although the windows don't steam up much. We have moved furniture away from the wall and scrubbed with mould remover, and have just installed a dehumidifier, which is already pulling moisture out of the air.

But how can we warm up the wall? If we replaster, then it would make sense to install insulation-backed plasterboard, but would it be worth looking at cavity wall installation? I don't think we have it at the moment (1930s bungalow).

More money-spending opportunities....

I'm staggered that there is a new build without windows, just patio doors!

With my windows I can open them a crack and then lock them. Is that an option?

Yes, and it is not expensive. See if your gas or electricity supplier has a scheme, or BG if not. IMO they are more reliable than doorsteppers.

You also need to upgrade the ventilation, and avoid wet washing.

(That was to Cointreau)

I have cavity wall insulation and very pleased as there are no houses on one side of the street and the wind howls in winter.

Some of the plugs look ugly though where they inject it. I cannot understand why they didn't drill and inject on the mortar joints and not through the bricks. That way it could have been made to look invisible with a dab of mortar

I think perhaps it is an extractor fan not a dehumidifier. There is (should be) a duct taking the steam outside through a gable wall, or the eaves, or though a special tile.

The duct is in the cold loft, so the steam is condensing inside the duct.

Things to fix:

Rigid duct is smooth inside and may catch less dust and condensation than the flexible hose.

If the duct slopes downwards towards the wall or eaves, condensation will run outwards, instead of towards the bathroom.

If the duct is wrapped in loft insulation, it will be warmer and so less prone to condensation.

A powerful fan with a run-on timer has more chance of clearing the moisture than a weak one.

It is possible to fit condensation traps, but how would you empty them?

We have terrible condensation in our bedroom, when we wake up the windows are dripping wet. I wipe them down with towel then open all the windows and close the bedroom door. I leave it like that for an hour, and there's no more problem during the day.

We're getting secondary glazing fitted in a couple of weeks, so I'm hoping that will make a difference.

Can I please jump on the bandwagon with a quick question. We're in a 1930s detached house with single glazing all round. This year, so far anyway, the condensation has been awful. We have the fanlights open all night, but there have been pools of water on the windowsills these last couple of days.
The windows are in a right state so we're just in the process of getting double glazing quotes... will this make a big difference with regards to the condensation? I don't dry clothes inside at all. I don't remember it being this bad last year

Have you got a water meter?

Me? Yes we have....

Turn off the taps.

Look at the meter.

Is the bubble still turning?

PigletJohn - apologies for not directing my question a few posts back. Do you have any insights that would help me please? Or anyone else?

Draped washing is a bad source of condensation, damp and mould. If you have to dry it in the house, put it in a room with an effective extractor and close the door and window until it is dry.

We are looking for the source of the water which is causing the damp.

A modern build or conversion ought to have a damp-proof floor, but the floor may be damp if there is a plumbing leak, or if the outside ground level is raised, or sometimes if there is penetration e.g. from water running downhill towards the house. If it is a concrete floor, tape a piece of clear plastic tightly against it and see if water forms underneath. Sometimes radiators or their pipes leak. This is easily detected if you have an unvented boiler with a pressure gauge on the front, as the pressure will drop.

Really enjoying this thread. Learning so much but I also have a question for PigletJohn (or basically anyone with more knowledge than me).

I have a humidity sensor (bought from Amazon for about £4, I love it). At the moment it's showing 67% inside. The link to the MetOffice site up thread (excellent link, thanks so much for posting that, can't remember who it was) is currently showing 76% for my area. Does that mean that I SHOULDN'T open the windows to air the room? Surely then cold, damper air gets in and hot, drier air escapes?

All the advice seems to be to open the bedroom windows when you get up, but that seems to be the dampest part of the day. This morning it was 95% and raining so opening the windows then would have seemed counter productive. Hope that makes sense.

open the windows.
as piglet has already explained, cold air cannot hold as much moisture as warm air which is why you get condensation on cold surfaces, as the air cools down and has to gef rid of the water.

as long as inside it's warmer than outside the warm moisture rich air is exchanged with colder dryer air (which is why heating as well as ventilating is important)

the number for humidity is expressed as RG % (Relative Humidity), being the amount of water it contains, proportional to the amount of water it could contain, at that temperature. If you hang a wet pair of socks on the line in low RH, they will dry quickly. In high RH, they will stay wet.

The RH varies with temperature. On a frosty day, when all the water has crystallised into ice, there might be about no water left in the air, yet RH might be about 100% because water will not evaporate into it (your socks will not dry much in frost). Bring that cold air into your house and warm it, and the RH figure of that air will tumble, even though the amount of water in it has not changed.

This is why a cu.m of hot dry air (low RH) in the Sahara contains more water than a cu.m of cold damp air (high RH) n Glasgow.

"is expressed as RH %"

Marvellous science lesson!