Heat recovery unit reviews??

[hiking bear]

My pre war 2 bed bungalow suffers from Condensation, mostly in the morning. Ive tried the usual things including dehumidifiers which although collect plenty of water do not stop the condensation. Average humidity is 73% - 80%. As a last resort ive been looking at a loft mounted heat exchanger/ventilator. Obviously the manufacturers all give good write ups but i would like to hear from someone whose actually got or had experience with one and the end results. Im also open to any other suggestions and advice regarding condensation.

[Perry525]

This is something I wrote for someone else, it is relevent.

From what you write, it looks like a classical case of lack of ventilation.

To understand what is happening you need a decent hygrometer with an external sensor, where you can see whats going on and adjust the level of humidity in the home to reach a compromise between the recommended level and what you feel happy with.

I would guess that you keep all the windows closed to save on heating costs and manage to create a lot of water vapour in the home at the same time.

The solution. Any, or all of the following.
Leave the windows open for about an hour in the morning and evening.
(to start with and gradually reduce the time as the problem goes away
down to five minutes in the morning) This means loosing all your heat along with the water vapour. (expensive)

Stop turning off the heating, or stop turning it down. (This pushes up the cost but, leads to a warm, comfortable, pleasant to live in home.)


You need a quick result!
Buy a de-humidifiers with a 10 litre capture rate per 24 hours. (They don't collect 10 litres a day as you need perfect conditions for this, but will do the job.)
Plug it in and keep it running 24 hours a day.
They don't need to be in the bedrooms, just leave the bedroom doors open all the time.
Yes they will be noisy but, as they get the problem under control they will be on less and less.
You will be surprised to see that they will capture about two litres each, every 24 hours.
After a few days the amount will drop, and gradually as you run through the year the amount
will decrease until in about a year or so it will be down to perhaps half a litre.
And your home will feel nice again.

The problem is probably due to your life style habits.

I imagine you do not have a problem during the warmth of summer?

Do you have the windows closed all the time?
Do you leave the kitchen door open when cooking or after cooking?
Do you have a extractor fan over the cooker and do you use it?

Do you use the extractor fan while washing?
Do you leave wet towels on the radiator?
Do you leave the bathroom door open after washing?

Do you dry clothes on radiators?

Do you have a tumble drier that is not vented to the outside?

Do you have flowers and plants in the home?

The above are the main causes of water vapour in the air and condensation on walls, windows etc;

We all breath and sweat, and we all produce about 2.5 litres of water vapour every 24 hours,
active children and animals produce more, old people less.

At night we each produce around 330 ml of sweat just controlling our temperature and this goes
straight into our beds and bed clothes making the beds feel cold.

This moisture either needs to be vented to the outside, the outside is nearly always drier than
the inside of our homes, or it needs to be soaked up by a de-humidifier.

Water vapour in our homes, is precipitated by a drop in temperature.

When the heating is turned down or off, the water vapour in the air drops out and usually
forms condensation on our windows, window frames, or the reveals round the windows.
When we draw the curtains, the temperature in front of the windows drops and cools the
air and the water vapour drops out and causes condensation. This forms when the out
side temperature drops to 11 degrees C or lower and you see a slight misting in the corners of
the windows.
Condensation also forms behind cupboards and anything that stops the warm air in our homes circulating.
I hope that helps.

[big bruv]

Sorry to jump in perry525 but could you have a look at this thread for me (sorry i can't PM yet) damp-patch-on-out-side-of-exterior-wall-t15955.html many thanks