Are Dehumidifers Dangerous?

[Jennykenny]

Got a few damp patches round the house.
Any suggestions on the safest way of dealing with this.
Are the chemicals used in the non-electric types dangerous?
Should I just pay more and get an electrical one?

[gingejbee]

I think that the most likely advice on here is....find out what's causing the damp patches and deal with them. Using a de-humidifier is very "second best" and may not even improve the problem.

[ivor4781]

i think the non type are mainly used to keep windows clear and not very good at that, electric ones are more efficient and dont that use much power, but get one that has a humidity sensor to switch on and off otherwise they will run till you turn them off

[ivor4781]

gingejbee has good advice check whats causing it before laying out the money

[retrocop]

I paid out for an electrical de-humidifier for preparation of a wall for remedial work. Our eaves bedroom cupboard was letting in damp so we bought quite an expensive de-humidifier and had it on in the cupboard for several days.This was as a result of the plasterer/decorator's recommendation. It collected not one thimbleful of water. Waste of money and sitting redundant in our garage.

[Jennykenny]

This advice comes from my builder.
He uses them in his home. He reckons that because we have our houses sealed so tightly with double glazing, loft insulation etc, then we can't help but have some damp.
I have had the Dutch system of bricks on all the outside walls installed, and one of the kitchen pantries and under the stairs stripped back, sealed and replastered.
When we bought the house we noticed that the seller had dehumidifiers in some rooms. It's a lot better than it was then but still a relatively small problem, which I can't get to the bottom of.

[chiaroscuro]

Dehumidifiers that use a compressor work very poorly at low temperatures so if it's going to be used in an unheated room you need one that uses a desiccant wheel. This type is always used to keep cellars, boats, caravans etc from getting damp.

[The Builder]

Ginge has it right in my opinion. You're dealing with the symptoms rather than the causes.

I take your builder's point, but modern "sealed" properties are no problem at all as long as the fabric of the house is kept at a reasonable, steady temperature, and EVERYTHING that produces water vapour is ventilated.

Bathrooms; showers; cookers (especially gas); tumble driers; clothes drying etc. It's not practicable to stop breathing, but window trickle vents do help with that ;o)

[Jennykenny]

Thanks, The Builder.
I open the bathroom window after every shower, but I do dry clothes on the radiator.
I have a gas cooker with a hood, but rarely use it.
Don't have a tumble dryer.
Don't know what a window trickle vent is but will look into it.
Many thanks to all for your comments, suggestions.

[ummmm]

When we had a flood (burst water tank in the loft) we were provided with a dehumidifier by the insurance company. It was a massive industrial one that was on 24/7. It still took over two weeks for the walls to dry out. The amount of water was quite shocking.

[chiaroscuro]

I had to laugh at TheBuilder's advice to replace your double glazing with the latest sort fitted with trickle vents when you were agonising about paying for a dehumidifier - best of luck with that.

[The Builder]

No, no, Chiaroscuro. Trickle vents can be fitted to existing windows :o)