How best to combat condensation?

sir_shanahan

Perhaps I can ask this better. As long as there is any kind of temperature difference between the inside and outside of my flat, condensation will always form on the northern wall. This is simply due to poor design in the flat itself but is compounded by my breathing at night, when it is coldest outside. For security reasons I must have my bedroom window fully closed at all times when the flat is empty. When my girlfriend and I are home we require the flat to be warm enough to warrent us paying rent as opposed to living in a tent somewhere. It does not have to be warm enough to support a nudist lifestyle but it would be nice to be able to see the tv through our breath...
There are no window vents that can be opened that are not already opened. All interior doors are open all night to improve circulation between rooms and there is a small window in the bathroom as well as a larger window in the living room that stay open all night. Opening any more of the flat to the elements would mean that we would have to run heaters all night, at least in the bedroom.

If there is a solution to this problem using added wall or window vents then I'm sure that would be the cheapest and simplest solution in the long run, I just don't know what sort of impact that would have on the level of condensation. It would probably have an adverse effect on heating/insulation.

The flat has a built in Air Heating System. I am told that this will dry the air in the apartment sufficiently but is expensive to run and must be run for long periods of time to be effective.

Another possible solution would be to purchase a dehumidifier. These come in a couple of types. The cheaper ones really aren't all that cheap and at about 300W they don't look too cheap to run, given they have to be on for the best part of the day, all day... The cheaper ones also tend not to perform so well below about 45% humidity, or when ambiant temp drops below about 20C. Opting for a more advanced type I could overcome these constraints but would maintain the same running costs, meaning all in all more money.

As pure speculation I'd say that a lesser model dehumidifier would do, based on the the premise that my flat will rarely go below 20C and given that I live in England, the humidity should stay above 40% most of the time...

This is all I know about dehumidifiers so I am really reaching out to anyone who does know more. Or who knows much about Air Heating Systems (I've never used one), or even someone who has had (or still has) similar problems...

I'm well aware that there are all sorts or weird and wonderful ways to skin cats, what I am really looking for is an economical, effective solution that will make our lives a little more comfortable. If the only option available is to open the place up to the world then we may as well move the bed down to the garage and sublet the flat out. This is the United Kingdom we live in and the internet opens us up to the world. Surely we are not the only people to have encountered such a problem and I sincerely hope that there is someone (or some milliions) who know more about the science and technology of these solutions than I do...

Many Thanks...

sir_shanahan

Thanks Kittie

I'm trying to get my head around that. We already do as you suggest with the shower. I was considering getting a dryer form of heating and hoping to get rid of some of the moisture that way. The question then becomes 'how much difference does it make?' I won't know the answer until I try and by then I've already spent the money...
I think it's becoming clear that this is a problem I will have to spend money on to fix, all that remains now is to find the cheapest option...

Once again I put the question to the people...

Cardew

What do you mean by a small oil heater? A portable oil burning heater or an electric oil filled radiator?

As you are in a top floor flat, rising damp can be ruled out; therefore your problem of condensation is just lack of ventilation. You have either got to increase ventilation(We do understand your dilemma about heating costs) or use a dehumidifier.

Heating a room does not solve the problem of poor ventilation, it only masks the problem by the warm air holding more moisture.

Even cheapish dehumidifiers, big enough for your small flat, usually have the ability to set a certain humidity level(say 60%) and they cut out when that level is reached. However some can be quite noisy and I would not like to try and sleep near one whilst it is operating.

mummyroysof3

we have damp both upstairs and down in our house, we have 2 dehumidifiers so one is on at all times, i havent worked out how much more it costs but we pay £45 electic per month, there are 5 of us in a 3 bed house. the coldest part of or house is the front and side walls and in the winter we have a small oil filled raidiator we run in the boys room over night on the outside wall as our youngest child has a cot on that wall. by next winter they will have bunk beds so hoping that means we wont have to worry about that, i hope you find a solution to your problem but id think a dehumidifier will be needed.

charlotte

21stCenturyPioneer

There is a lot of info here, but I hope I can help.

Dehumidifyers come in 2 sorts, a decassident one (sorry not spelt right) or a comressor one.

I can thoroughly recomment the decassident type for several reasons, they are multi function devises, so may help you save a little. They of course dry the air out, but this kind of machine works by heating the air it releases back into the room, and they do make it noticably warmer while drying. The second function they perform is the drying of clothes and ours has a special dry function on, its great and clothes will dry in a few hours, so again you are killing 3 birds with one stone. Its drying, its heating and you will be saving on the tumble dryer.

Also you can set them onto AUTO and they will basically only come on when needed, and once the dampness is under control its surprising that it does not need to be on that much.

This auto control also saves pennies by it not drying all day, but its interesting to see the various things you do change the moisture content.

for example ours may be on idle, then someone takes a bath, the machine will start in a few mins so its interesting to see how fast it senses the various activities.

Also dampness migrates to dry areas so you can pop it into a central place / room and leave it there, it should then help the whole house.

I thin jyour problm is that you cannot leave the windows open in the day time due to security, since that is what we do to try and let the house dry out, it makes a big difference. then close them when it gets cold in the after noon.

Since you cannot do this then I really thin the dehumididyer is your only option, but if you pick the right one I think it will work out well as a dryer, heater and replacement for the tumble dryer.

We never paid them much mind before but its one item I would always have in the house now, and will be replaced when this one breaks down!

Pincher

Check out:

http://www.dealec.co.uk/acatalog/vent_axia_single_room_heat_recovery.html

Don't forget the PIR and humidity sensor versions.
The unit runs slow normally, and fast when it detects people and moisture.

"Mr. landlord, I want to drill a 152mm hole through your wall, and run a power cable to it." Good luck.

samtheman1k

Preventing condensation is quite simple, either get rid of the water vapour (ventilation), or heat the walls to prevent the vapour from condensing (or preferably, a combination of both). In in order to retain a certain temperature in your flat, then you will need to use heat for both options. That is physics unfortunately. There is no magic solution.

What is the power consumption for your warm air system? Is it more or less than your small heaters & humidifier combined??

Putting vents in walls/windows is not cheap, and probably will cost more than just putting your warm air system on! Perhaps look at getting storage heaters put in if you are that worried about cost, I'm assuming you don't have access to GCH??