What is a dehumidifier actually for? I know it extracts moisture from the air but does it prevent damp?

Question

I have a problem with damp on a wall in my flat and think that maybe its because of a lack of ventilation, would a dehumidifier help to prevent the dampness?

Answer 1

I think a dehumidifier would help but only if you firstly addressed the cause of the damp. I'd firstly sort the damp problem out and there are several ways you can do this. Is your wallpaper getting black damp spots on it? If so, I'd firstly, take the wallpaper off that part of the wall....strip right back to bare wall. You can buy damp-proof "paint" to paint on and then repaper that patch.

I've used a dehumidifier for about 20 years - I had a damp prob in my first flat and although the dehumidifier did help (ie once I'd washed the paper and cleaned the spots off), and ran the dehumidifier 24/7 in that room, the spots never returned. Instead of moisture being attracted to that part of the wall, it was attracted instead to the dehumidifier, which then distilled it into a little tank for me to empty. I use it now in my 4 bed house mostly in the autumn/winter, when you notice condensation on the windows. A few tips about them, they're really cost effective...they cost no more than an average light bulb to run. They will suck the moisture right out of everything so be prepared for your plants to get drier and you'll have to water these more often; you will wake up the first few days with a dry throat (but that goes once you get used to it). You'll feel a difference in your skin - it will be drier each morning you wake up so use a good night moisturiser! It's great for helping to dry your laundry, especially if you put it on an airer in the same room, or just hang something above it! They also give out a little bit of heat, not due to overheating, just that the fan turns out warm air rather than cold, so it actually adds a little more heating to the room!
My first one was an expensive Ebac (best known manufacturer) and cost about £240 about 20 years ago! Since then I've had a Tatung which is white and much smaller and cost about £80 10 years ago (and I haven't noticed a difference in quality...actually I think the Tatung works better). So, don't be sucked into the big brand names you see.....the lesser known, cheaper ones are just as effective. And mine is a really quiet one. If you can, get the salesperson to demo it so you can assess the noise level....it should run really quietly so it doesn't disturb your sleep. It should have just an on/off button and it should switch itself off automatically when the tank is full. Empty the tank and put it back in and it should automatically switch itself back on again. The only problems I've had with mine in the last 15 years are that the fan and filter tends to get very dirty/dusty and sometimes this can cause it to stop completely and you think it's broken. But I'm pretty capable of taking the side off and dusting that out. And it's worked again every time since. In 15 years I've done that about 5 times! And that's it basically.
I'd say try a dehumidifier....there are other advantages to it and it should help with your damp problem, especially if you keep it in the same room where the damp is. Cosmetically though, you need to actually address the cause of the damp as I said earlier because if it's a blocked vent or rising damp etc, something that will keep coming back, the dehumidifier will only slow it down, not prevent it. And I'm sure there are many more people in here who could give you advice on how to address the damp source.
I hope this has given you a little more info - I wouldn't be without mine now and I haven't got a damp problem, but it's great just to get rid of all the condensation on the windows during autumn/winter and for helping get clothes dry! Good luck with it.

Answer 2

This Site Might Help You.

RE:
What is a dehumidifier actually for? I know it extracts moisture from the air but does it prevent damp?
I have a problem with damp on a wall in my flat and think that maybe its because of a lack of ventilation, would a dehumidifier help to prevent the dampness?

Answer 3

Yes it will help prevent dampness. There is always moisture in the air, this is necessary for us to feel comfortable. However, most homes at one time or another suffer from excess moisture and, where there is insufficient ventilation in a house, moisture levels can build up to a point where damp becomes a problem.
Depending on the severity of the problem excess moisture may cause anything from water on the walls and pools on the windowsill to mould and peeling wall paper.
Dehumidifiers draw the excess moisture out of the air.
During our daily routine we can be adding more than 11.5 litres (20 Pints) of moisture into the air in our homes, this comes from:
Cooking / Bathing/ Washing machines and dishwashers/ drying clothes indoors/ open fires including gas flame heaters/ Breathing.If this moisture cannot escape it will build up and then find its way to cold spots in the house, for example a window, and condense (Turn to water.) That’s where problems start.
Dampness is caused when moisture laden air comes in to contact with a cold surface, such as a window or North facing wall or even inside a wardrobe in an unheated room. The air coming in to contact with these cold temperatures will deposit its moisture on the cold surface. The condensation then starts turning in to damp resulting in mould and a host of other problems.

Answer 4

The De-humidifier while it will REMOVE damp, It will not CURE it. The wall may be damp for a number of reasons. I guess this is an outside cavity brick wall. Check that any gutters/ pipes are sound, and not spilling water over the wall. Check the air-bricks are not blocked, from the damp proof course up. The damp-proof course should NOT be 'bridged' by anything, typically earth. It is also possible that if this presents as a patch, it is a wall tie bridged with mortar or such.
May also simply be a cold wall, being cold the moisture in the air will condense on it, thus air movement in that area will prevent /dry out moisture. DIY stores (Homebase, B&Q etc) sell a liner called "Warmaline" like thick polystrene wallpaper, the object being to create a warm barrier on the wall.

Answer 5

By condensing warm moist air on a cold surface, just like a cold glass in the summer will sweat. In the back of a dehumidifier there will be a coil that is cooled by a compressor (think small refrigerator). A small fan will circulate warm moist air over the coil and the moisture will condense and fall into a catch basin under the coil which needs to be dumped out. The cycle of blowing air over the coils will remove the moisture from the air and make the air "feel warmer", hence dehumidifying.

Answer 6

For the best answers, search on this site https://shorturl.im/ax5gv

A dehumidifier is similar to an A/C system it has a refrigerant compressor that sends sub-cooled refrigerant to an evaporator coil that is cold. The air goes thru the coil and it "sweats" removing the moisture out of the air., the difference is that it usually has the condenser coil in the same airflow stream to re-heat the air as it exits the dehumidifier

Answer 7

I own a property that is used infrequently as a workplace & I had a problem there with damp due to lack of ventilation. Popped in a dehumidifier & problem solved!! No more patches of mould or damp walls. Wonderful & fairly economical when you weigh up the problem it's solving - and solve it it certainly does.

Answer 8

I work for speedy hire centres and we hire these out what they are for is simple . They extract moisture out the air to prevent condensation . For example . you lay a new carpet while you are doing this you spill something on it . If the room is cold it wont dry out , A dehumidifer would suck all the moisture out the room and store it . So the answer to your question is yes it would prevent damp if you left it on for a few hours a day .

Answer 9

I guess as you can tell from the others the answer to your question is yes, however you are only treating the symptoms not the disease. it would be far better to repair the cause of the damp in the first place then use the de humidifier to dry out the room. without treatment the structure will deteriorate rapidly and you will eventually need more and more de humidifiers to keep up! very expensive!

Answer 10

I would think so.When you have newly plastered walls it makes them dry twice as quickly & you empty water out of a dehumidifier so it must help rooms dry out & help damp because its taking moisture out of the room.