Cheapest Way to Sort Out Condensation

kittycatface

We live in a stone wall house (rented) with aluminium framed glass front door, aluminium bay window and two huge aluminium window frames on the first floor. We have had problems with damp and mould ever since we moved in 2months ago. Landlord has been in with experts but the worst thing is the condensation which pools in the window frames to the point where I am mopping up more than twice a day.
He is saying it is condensation caused by us, which it may be as we can only afford to have heating on for 2hrs each day (tbh I don't even want it as much as that due to cost).
We are living on £5,000 grant money for my studies plus a couple of thousand savings and partner is currently jobhunting with a vengeance. We pay £65 to Coop each mth for dual fuel.
Landlord has lent us an oil filled radiator (no idea how much that costs to run).
At the moment we have no airing cupboard to dry our clothes, radiator racks only and still the clothes aren't getting dry.
We can't afford to heat the house more and he is saying we should air the rooms more (its freezing up north(!) and we are worried about losing valuable heat if doing this in evenings.
Every time I cleaned the mould even with biological washing powder solution it keeps coming back.
We only dry clothes once a week and use extractor fans in bathroom and kitchen. What are we doing wrong and how can we do it better and cheaply!?
Would it be:
Cheaper to use laundrette to dry and or wash clothes?
How much does oil filled 600w radiator cost to run?
Is it cheaper to turn off some of the radiators in the house and only keep one on in room where there is a mould issue?
Cheapest place to buy radiator foil?
PS: Our boiler takes around half hour/45min to heat any water is this normal?
thanks for reading the essay! any advice gratefully received.

grizzly1911

Two ways to stop condensation, keep water vapour down to minimum and ventilate, even trickle ventilation is better than nothing. Open the kitchen bathroom window for a while when you have finished until you can see you face in the mirror and leave the ventilation fan running longer.

Heater depends on your tariff but up to 10p/hour wouldn't be far off.

Use diluted bleach on the mould, maybe an old toothbrush to get in the cracks, and wipe off after 30 mins it will kill the spores.

If the tank is cold then 30mins+ would be fair to have a reasonable amount of water, probably not fully warm through though.

Cooking foil stuck to some suitably sized cardboard box would be the cheapest way to create a radiator reflector.

Consider spreading your washing out over the week so you don't have a lot damp all at once. If you have a lot of heavy stuff, towels/jeans and you can't air dry a little then a launderette drier might be a good idea for those items.

Keeping the heat on lower and concentrating heat in one room especially if the oil rad has a thermostat may be the best option.

Cardew

Ventilation is the key to preventing condensation - not heating. All heating does is enable the air to 'carry' more moisture(humidity) that moisture will still form on cold surfaces. In fact condensation is more of a problem in sub-tropical climates where properties getting too warm rather than too cold is the problem.

The best solution is to get a dehumidifier. These 'suck' out the moisture and at the same time produce some warmth.

ariba10

Have a read of this. It worked for me.

http://www.harfordsonline.com/downloads/condensation%20info.pdf

grahamc2003

Instead of a 600w electric heater, you could run a 600w dehumidifier. You'll even get more heat from the dehumidifier than you would a heater of the same rating. In addition of course, the dehumidifier would be doing what you require, and taking water out of the air in your room. I'd go with a dessicant type, avaliable new for £110 or so, since they work at low temperatures and give out more heat than compressor types, which don't work at low temps (say below about 8C, but the extraction ability drops off well before that).

Drying clothes next to a rad is of course doing the opposite of what you need - you're putting lots of water into the air, likewise drying wet towels in the bathroom after a shower, or drying inside the cloths you've used to mop up the condensation off your windows.

You could by a hygrometer to measure the humidity - I just got one off ebay for a couple of quid. If it reads over 80% relative humidity, you're likely to keep getting mould whatever else you do. 50%-70% RH is the recommended 'comfort' level - don't expect to reach those levels quickly, could take weeks since the whole fabric of the house and funriture will hold lots of water if you've had a damp problem for a while.

rogerblack

Several misunderstandings in this thread.
Firstly, that you shouldn't have condensation single glazed windows in a non-damp property.
This is totally incorrect, some degree of condensation is normal.
http://en.wikipedia.org/wiki/Dew_point - specifically the chart -

With single pane windows, when there isn't any external wind, the temperature of the window reaches halfway between the internal and external temperature.
If the outside temperature is 5, and the internal temperature is 25, then the window will be at 15C.
Looking at the chart above.

To the left of the leftmost blue line, water is condensing out, as the air can't hold any more.
So, at what temperature will air at the 50-70% start condensing water?
Find the 25C line, now count down to the fourth blue line - this is 70% humidity.
Now, how far to the left - low down in temperature can you get before hitting the left blue line where it'll start to condense?
At about 18C.

And at 50%? 13C.
The original poster has it significantly worse, they've got aluminium windows, presumably without a thermal break.

In any slight wind, the outside of these will be efficiently cooled.
This means that the frames will be close to air temperature outside.

Using the graph in a different way, and looking at 10C outside temp, with a wind blowing on the frames, you need a humidity of only 40% for the frames to start getting moist at 25C internal temp.
To get to a point where you're not seeing condensation at 5C, you're looking at more like 20%.
This is desert-like.

Secondly, on desiccant dehumidifiers.
These are essentially useless.
A normal mains one takes out around 10l a day (this varies of course).
Unless you are buying literally a bucket-full of desiccant a day, and disposing it out of the house, you can't remove this much water.

Unfortunately, there isn't a good answer to the original poster.
The building they are in, unless well heated, will be damp unless they ventilate significantly - and by significantly I mean have a window open enough to drop the temperature noticably.
If the building was heated to 20C, then it would be lots drier, and most of the problems would 'dry up', as the moistness can be removed by fairly small amounts of air removed.

If it's not heated to those levels, the amount of moisture will be significantly higher.
Dehumidifiers will help reduce the amount of condensation - but only once the building is adequately heated, they won't do much otherwise.
In addition, someone mentioned that mains dehumidifiers don't work very well under 8C. This is a misunderstanding.The amount of water in the air has fallen dramatically by 8C, even at 100% humidity, so the dehumidifier has to process more air to get the same amount of water, and its output drops.
from http://en.wikipedia.org/wiki/Relative_humidity

The left-hand axis is the amount of water in the air.
The most the air can hold at 25C is about three times that at 8C.
This is why mains - or any other dehumidifiers start to suck as you go lower in temp.

One thing I found useful, when living in similar conditions.
I was drying the washing in the bathroom, with the addition of a fan heater, and a dehumidifier.
This allowed it to dry quite rapidly.

The only things the OP can do are:
Try to work out some means of drying that will not release moisture into the house.
Reduce the amount of steam you produce when cooking.
Pay attention to pots, cover them, turn them down so they do not steam, but simmer, covered.
Do not reduce anything on the stove without a window open.
Ventilate a little more, wear more jumpers.

Wow - this was a bit longer than I'd thought.

Ben84

grahamc2003 wrote: »

Instead of a 600w electric heater, you could run a 600w dehumidifier. You'll even get more heat from the dehumidifier than you would a heater of the same rating. In addition of course, the dehumidifier would be doing what you require, and taking water out of the air in your room. I'd go with a dessicant type, avaliable new for £110 or so, since they work at low temperatures and give out more heat than compressor types, which don't work at low temps (say below about 8C, but the extraction ability drops off well before that).

I've been really pleased with my dehumidifier, it helps a lot for the difficult to avoid moisture. They do emit some heat, but I would question how it could be more than a radiator of the same wattage? While they don't use electric elements and rely on a CFC cycle like a fridge, which emit more heat per unit of energy input, the air passes over the cooling pipes then over the heating ones, making the extra heat emitted appear to vanish as you're moving heat rather than generating it. Running any process that moves heat within a sealed room space will have no overall net gain. Of course the condensing water vapour emits heat when it changes state, but to be honest while my dehumidifier is rated at roughly 380 watts, placing my hand next to the vent when it's running I find the air to be slightly warm at best. So, I wouldn't consider it a very good heater and don't believe I'm getting much more than 380 watt of heat from it. However it does remove a lot of water from the house every day.

A side benefit may be that less water in the air means less condenses on the windows and transfers useful heat to the glass and out of the house.

grahamc2003

Ben84 wrote: »

I've been really pleased with my dehumidifier, it helps a lot for the difficult to avoid moisture. They do emit some heat, but I would question how it could be more than a radiator of the same wattage? While they don't use electric elements and rely on a CFC cycle like a fridge, which emit more heat per unit of energy input, the air passes over the cooling pipes then over the heating ones, making the extra heat emitted appear to vanish as you're moving heat rather than generating it. Running any process that moves heat within a sealed room space will have no overall net gain. Of course the condensing water vapour emits heat when it changes state, but to be honest while my dehumidifier is rated at roughly 380 watts, placing my hand next to the vent when it's running I find the air to be slightly warm at best. So, I wouldn't consider it a very good heater and don't believe I'm getting much more than 380 watt of heat from it. However it does remove a lot of water from the house every day.

A side benefit may be that less water in the air means less condenses on the windows and transfers useful heat to the glass and out of the house.

Any dehumidifier will give out more heat than a heater of the same rating, simply because to condense water the latent heat of evaporation is released on top of the heat from the conversion of electrical energy. (The heat generated by any electrical appliance is the same as its electricity used, whatever else it does - e.g. my surround system uses about 35W, so it produces 35W of heating, even though some of the energy has gone through an intermediate state of vibrating the air and my eardrum before the heat is released).

Likewise, to see the heat produced by a dehumidifier, you simply add up the latent heat of the condensed water to the power rating (say 250w for a refridgeration cycle type, or 400W-800W for a dessicant type) (I should mention here that a previous poster trashing dessicant dehumidifiers simply doesn't know what they are, and also has some terrible and inaccurate advice too). A resistant heater simply produces heat at the same rate as its power rating, obviously.

In your case, 350W of heating (I assume yours is a fridge cycle one) in an airflow isn't very much at all, so the exhaust air will only be slightly higher than the room air temperature, but it may even feel cooler due to the 'wind effect', where moving air feels colder than stationatry air.

Dessicant dehumidifiers have heating elements, and depending on the setting, can throw out about 800W of heating (plus the latent heat of course), and that can easily be felt in the exhaust air.

Your final point is correct. The lower the humidity of the inside air, the lower the dew point temperature, and the less chance of getting condensation on the windows (with the consequent loss of latent heat conducted through them).

grahamc2003

rogerblack wrote: »

In addition, someone mentioned that mains dehumidifiers don't work very well under 8C. This is a misunderstanding.The amount of water in the air has fallen dramatically by 8C, even at 100% humidity, so the dehumidifier has to process more air to get the same amount of water, and its output drops..

Roger, you state several times that people on this thread are 'misunderstanding' the situation regarding humidity and condensation. I'll just take this one point from your error-filled post to illustarte that it is you who demonstrate 'a little knowledge is a dangerous thing'.

The reason fridge-cycle dehumidifiers stop working around 8C is due to them freezing up - the coils get to a sub zero temp, and instead of condensing (that is going from gaseous to liquid state) the water deposits (that is, goes from gaseous to a solid state, i.e. ice). The coils ice, and sensors turn the humidifier off.

Dessicant dehumidifiers (and you need to google to see what they are instead of saying they are cack when you don't even know they exist) work in a different manner, and don't experience icing at all, and efficiently extract water down to zero degrees.

While the absolute amount of water capable of being held in air lowers as the air temperature does, then exactly for the same reasons, conmdensation becomes a much worse problem the lower the temperature. It's probably more important to extract less water from cold air than it is more from warm air, if condensation is a problem.

Pincher

Have to say we used to open the windows to ventilate and wipe the condensation from the double glazed aluminium frames without too much effort. The central heating was on, but we opened the bathroom window with the bathroom door closed after a bath. The toilet had a permanent vent.

If you really don't want to open the windows.


Traditional bathroom fans:

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


If the landlord is willing to bring an "expert" in, maybe he is willing to fork out for one of these:

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


Most of the distribution air ducts are in place for this stuff in my house.

http://www.dealec.com/acatalog/wholehouse_ventilation_and_heat_recovery_systems.html

Cardew

The problem as stated in post #5 is that once a house/flat has been damp for a long while, the very fabric of the building(walls/ceiling/floor) and the furniture becomes damp and it can take months for this moisture to be extracted. Just ask the people in the West Country who had their houses flooded; a year on and they still aren't habitable, despite all carpets and furniture being thrown away.