Dehumidifier- A Lire A Day?

[Jennykenny]

Noticed some damp patches in a corner of the living room, on the wallpaper, so set up the dehumidifier and over the last five days have 'pulled' a litre of water out of the walls. Have it going for 6-8 hours a day.
This seems an excessive amount of water? But obviously it must be in the walls to come out.
Any thoughts?

[murraymints]

need a damp course ? builder will give you a sensible answer

[ivor4781]

most of that will from normal humidity

[ladybirder]

Jenny that is a tiny amount. I have pulled 5 litres a day out for 4 days when I rented a property a few years back.

[Jennykenny]

We had a sort of damp course installed before we moved in (it came up on the survey, and we noticed the sellers were using dehumidifers in some of the rooms). We had this Dutch system put in where they insert special bricks in the outside walls. This was over six years ago and I thought that was the problem sorted.

LB that must have been scary.

I'll continue until the amount starts dropping, hopefully.
Thanks all.

[Gizmonster]

We have 2 dehumidifiers constantly on.
The one downstairs doesn't need emptying that much (once every 3 to 4 days ish); but the one in the converted loft needs emptying almost every day - I think the tank holds 2.5 litres.
We haven't had any work done recently and we've lived here for over 11 years now, so I'd assume that it's pulling moisture out of the air which is rising up through the house with the warmer air.

[ladybirder]

Actually Jenny it was wonderful. I saw the large black spots of mould on the window blinds gradually diminish and disappear completely in those few days. Magic;-)

[The Builder]

Jenny. I've never put any faith in de-humidifiers, except in extreme conditions as in drying out after a flood.

Two people living in an average house can produce around 10-15 litres of vapour per day. This is from cooking; bathing; washing machines; kettles etc....... and breathing!

Your "collection" is almost certainly NOT being taken from the walls.
Your damp patches are probably condensation. It settles on cold surfaces. Very likely on poorly insulated walls.

The only solutions are warmth and ventilation, and, if possible a higher level of insulation.

[fiesata]

Firstly buy a hygrometer to measure humidity - a few pounds on Ebay or Amazon Here's an example
http://www.ebay.co.uk/itm/Amir-LCD-Digital-Temperature-Humidity-Meter-Thermometer-Mini-Digital-Hygrometer-/282424415739?hash=item41c1ce95fb:g:NaAAAOSwc-tY57E0
Humidity should be between 40-60% If over this level then this can cause damp by moisture condensing to the coldest part of the room which allows mould etc to grow
If too high open windows in summer and consider having a humidity reducing extractor fan fitted these wil remove excess humidity much faster and cheaper than a dehumidifier
Example here
Amazon.co.uk User Recommendation

Paul