How best to combat condensation?

sir_shanahan

Hi All,

My girlfriend and I have just moved into a new flat. It is only a small 1 bed flat, probably no bigger than 12M x 12M split into a bedroom, bathroom, hallway and living area.
As the bedroom faces north it never sees the sun. A noticable amount of condensation collects here every day and even after 2 weeks we are noticing the early signs of mould.
The flat is double glazed throughout and on the top floor so we manage to be quite comfortable with only an oil heater on for an hour or two a night.
We have been looking at dehumidifiers and would like to find a cheaper alternative if possible. We live in the south UK so we are just coming in to winter. This means that the average indoor temperature will be about 15 to 25 degrees with outdoor humidity about 85% relative...
From what we have been told this would mean we would have to opt for a more expensive dehumidifier or heat the flat while running a cheaper one...
Neither of these options sound very cheap. We have several questions we would really appreciate some help with:

1. Given these conditions, what sort of dehumidifier would suit us best?

2. For a small flat, would it be possible to run a very small dehhumidifier? ( I doubt very much we'd need the 7-10L extracted every 24hrs, as many advertise)

3. The flat has an in built air heating system. We have avoided using it due to the cost of running it as opposed to a small oil heater. If we now have to run a 300W dehumidifier all day every day our savings will amount to nothing (if not negative). Would we be better advised to use the air heating system ( I can only imagine that it would help control the humidity, I am no expert)

4. If niether the Dehumidifier nor the Air Heating System is our most econimical solution, what other solutions can anyone suggest?

Any help would be greatly appreciated, many thanks.

-Shanahan

suki1964

You need ventilation, open the windows a wee bit or open the vents on them

My last flat had the same problem, the lass who lived there before me sealed all the air blocks and vents and used oil heating. Mould everywhere

sir_shanahan

Yes that was my initial thought. Sadly only the bathroom window has a vent built into it. We have been leaving a small window in the bathroom open at night (also on the north wall) as well as leaving a bigger window ajar in the living room (southern wall). While there appears to be no damp related problems in either of these areas there is still a large amount of condensation in the bedroom and it's getting too cold now to leave the window open at night...

suki1964

sir_shanahan wrote: »

Yes that was my initial thought. Sadly only the bathroom window has a vent built into it. We have been leaving a small window in the bathroom open at night (also on the north wall) as well as leaving a bigger window ajar in the living room (southern wall). While there appears to be no damp related problems in either of these areas there is still a large amount of condensation in the bedroom and it's getting too cold now to leave the window open at night...

This is where you need to open the window. The two of you in there at night is causing the condensation to form on the cold windows, so either open that window or dont breath

An oil filled rad on low would also help keep the room dry.

Took out the rubbish about the oil as in this case you are talking of a sealed heater and for some reason I was thinking calor gas

sir_shanahan

Hmmn Ok... So I think what you are saying is that it is a lesser of two evils situation? Basically I can pay a huge amount for a dehumidifier (80 to 300 pounds) and then foot the bill to run it all day or all night but not worry too much about heating costs... Or I can sleep with the window open, dramatically increasing my heating costs and bypassing any positive effects that double glazing might have on my flat?

If I seem a little unimpressed with this then I hope you realise I appreciate your help and direct any discontent at my landlord

I take it from your response that you either don't know about air heating systems or you have ruled it out as a solution?

Would a possible alternative solution be to install window and/or wall vents? I realise that this may also have an adverse effect on the insulating qualities of double glazing but I'm sure that the impact would be less that openning the window fully...

susank

CAn you open the window on a catch just a little overnight - I live north east scotland and we sleep with window open summer and winter as hate a warm bedroom and it does help with the condensation - sometimes there is ice though!!!!!!!!!!!!!!!!!!!!!!!!! if its really really cold!

sir_shanahan

It would be very cold with the window open all night and the big frosts are just starting... I too don't mind the cool air if I have a warm blanket but the missus is more the indoor type, sadly....

macman

Leaving a window open a fraction at night is not going to increase your heating costs unless you run the heating all night...

sir_shanahan

No, I understand that. What I am trying to get at here is that leaving my window open all night is not an option. I have offered several possible solutions here but as I am not fully versed in all these matters I was hoping that someone with a bit more knowledge of such things could shed some light on the matter and help me come to a decision.
I already have windows ajar all night in two of the three rooms that make up my flat. This has no effect on the condenastion in my room even if my bedroom door is open. In my opinion in order to draw enough air out of my window at night to seriously impact the level of condensation in my bedroom, I would have to open my window significantly. This is due to the fact that one whole side od my flat never sees the sun. So while there is added condensation in the bedroom at night from our breath, there is also condensation forming through the morning as the warm side of the flat cools on the northern wall.
As has been mentioned I could sleep with the window open and go with whatever humidity the elements throw at me (85% relitive at the moment) but I would still get a certain level of condensation due to the corridor on the north wall ALWAYS being colder than the rest of the flat. It's true I would be less damp but I would also be very cold a lot of the time... Or yes, I could stop breathing. Sadly this too is only half a solution as my breathing is not the sould source of humidity in Britain, so it's only real effect would be my demise...

Does anyone know anything about any of the other possible solutions I have put forth here? It really would be a big help...

macman

Leave the bedroom door open at night so that the water vapour produced by breathing is dispersed more evenly?
Somehow you need to improve the air circulation in the whole property.

[Deleted User]

you have to make some choices. First of all google `condensation` and get some basic info on how it is formed and the solutions will then become clear. Either: you need to reduce the amount of water vapour in the air if it stays cool ie without more heating. Take your shower in the morning and leave the window open afterwards is one suggestion or You need to increase the ambient temperature during the cooler hours as cool air holds less water vapour and any excess will condense. I would buy a de humidifier as mould can be a killer besides ruining clothes and furnishings. It is a big cause of asthma in susceptible people