Condensation problems after changing heating system

annem · 10 Dec 2008

We have recently changed over to gas central heating after 20+ years of using solid fuel.
During this cold spell I have noticed that first thing in the morning two of the bedroom windows are completely covered in condensation. This never happened with solid fuel. The fire would lay dormant during the night and the upstairs radiators would keep warm.
Besides leaving a window open (which I am reluctant to do because it's so cold) is there anything else I can do?

PerryOne · 10 Dec 2008

I am sure your home feels warmer since you changed to gas, open fires pull air from all sorts of holes and these drafts are what kept your home dry.
There are several solutions.
You can open the windows and let the water vapour out. (and the warmth)
You can stop breathing, as this creates 100% water vapour.
You can buy and use a de-humidifier, one that takes out about 5 litres of water per 24 hours should do the trick, as I would guess your home is otherwise dry?
You can keep the temperture steady, water vapour only drops out of the air on a drop in temperature. ie: air at 20C holds 18 ml of water per metre3, air at zero C is almost dry 5 ml.
Each of us adds 2.5 l of water to the air by breathing and sweating every 24 hours, animals more, old people less.

annem · 11 Dec 2008

Thanks.
I don't think the 'stop breathing' suggestion is an option at the moment

I've got a lot of living to do yet

I'll definately price up a de-humidifier; meanwhile I'll open the windows whenever the sun is shining and we think it's warmer than it actually is

Cheers

JohnD · 11 Dec 2008

in case of condensation, add ventilation.

If it isn't cured, add more ventilation.

Start with trickle vents, and opening the bedroom windows in the mornings.

Bedroom window misting is probably a combinbation of breathing all night, and recent very cold weather.

I hope you use extractor fans in bathroom and kitchen, and you don't drape wet washing about the house.

Make sure there are no water leaks adding to the moisture load, especially if you have had plumbing work done, and the boiler fumes and the condensate pipe are not leaking into the house.

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

annem · 11 Dec 2008

Start with trickle vents, and opening the bedroom windows in the mornings.

Bedroom window misting is probably a combinbation of breathing all night, and recent very cold weather.

I hope you use extractor fans in bathroom and kitchen, and you don't drape wet washing about the house

I find the smallest bedroom (with 1 large youth in it!) is the worst for condensation.
I've had the bedroom windows open all day today seeing as I'm on holiday from work.
We do use extractor fans in the bathroom and kitchen, but as there are 4 of us in the house, there is usually a towel draped over the bathroom radiator

I have been looking at de-humidifiers online and intend to buy one (which has decent reviews) tomorrow. Are they meant to be placed in a central point, for example would it be effective if placed on a landing?
Thanks for the link.

stuart45 · 11 Dec 2008

The problem with the small bedroom is that even though you open the window all day, it is probably closed at night when most of the condensation is produced by the large youth. By the time you open the windows it has already soaked into the plaster.

annem · 11 Dec 2008

Prior to us changing to gas central heating we had extra insulation put into the loft. Thinking along the lines of adequate ventilation, could this be another reason why we have condensation?
Can anyone recommend a decent reasonably priced de-humidifier?

JohnD · 11 Dec 2008

opinions differ, but I reckon ventilation (even allowing for heat loss) will cost less to install and run than a dehumidifier.

What are your windows made of, and do they already have trickle vents?

A dehumidifier is best used in a single room with the doors and windows closed (else it is trying to dehumidify the world)

annem · 11 Dec 2008

What are your windows made of, and do they already have trickle vents?

Windows are made of upvc and they don't have trickle vents. There is an option to lock the window at a certain point which allows about 1cm of ventiliation - I call it 'fresh air mode'

Do windows usually have trickle vents as standard?

JohnD · 11 Dec 2008

I'm not a window enthusiast, but I though they all did these days. You can actually drill the frames and fit little trims. If you post a photo of your frames someone will know more.

annem · 11 Dec 2008

Thanks.
I'll wait for daylight and take a picture - complete with a full pane of condensation no doubt...

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Condensation problems after changing heating system

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