Posted by
tsuiwah
19 yrs ago
I knew my flat was damp but didn't realize just how damp until today. Some hardcover books from overseas are all warped out of shape after just 12 hours in my flat. Living room is around 200-300sf (not enclosed) with lots of windows. Would a high capacity dehumidifier work in getting the dampness out? (Anyone have an extra dehumidifier they don't need and want to sell?) I guess I could turn on the AC but it is still a little too cool for that. Thanks.
Please support our advertisers:
They work, but in a room like yours you will need a professional one (extracts 25 litres or more per day). Also, make sure it has a large drain tank (10 litres or more), otherwise you will spend your life emptying it. The cute little ones will be useless in that room. For example, see
http://www.wingonet.com/product/product_detail.php?lang=en&prod_id=3135
Please support our advertisers:
raincatcher, yes - location makes a huge difference. Two of my in-laws live in the same development on different floors, both facing the same direction. The one on the lower floor has humidity literally dripping from the ceiling; but the one 30 floors higher doesn't even need to use a dehumidifier at present. (Or maybe it's the other way round: two dozen pre-pubescent nephews and nieces all competing for the same toy in one small room can dull the senses somewhat!)
Please support our advertisers:
@: I am sorry to be blunt, but that is complete BS. What you describe is a “water-cooled air conditioner” - these are only used in greenhouses, stables, etc. For residential/commercial building air-conditioning units your description is completely false.
In fact, air-conditioning DOES have a dehumidifying effect, and a dehumidifier works in a very similar way to an air-conditioning unit.
“How stuff works” has pretty good explanations for laypeople:
On air-conditioning:
“An air conditioner is basically a refrigerator without the insulated box. It uses the evaporation of a refrigerant, like Freon, to provide cooling. The mechanics of the Freon evaporation cycle are the same in a refrigerator as in an air conditioner […]
This is how the evaporation cycle in an air conditioner works […]:
1. The compressor compresses cool Freon gas, causing it to become hot, high-pressure Freon gas […].
2 This hot gas runs through a set of coils so it can dissipate its heat, and it condenses into a liquid.
3. The Freon liquid runs through an expansion valve, and in the process it evaporates to become cold, low-pressure Freon gas […].
4. This cold gas runs through a set of coils that allow the gas to absorb heat and cool down the air inside the building.."
(reference: http://home.howstuffworks.com/ac.htm)
On dehumidifiers:
“A dehumidifier is simply an air conditioner that has both its hot and cold coils in the same box. A fan draws the room's air over the cold coil of the air conditioner to condense the moisture (which normally drips into a bucket). The dry air then passes through the hot coil to heat it back up to its original temperature. That's all there is to it!”
(reference: http://home.howstuffworks.com/question76.htm)
Please support our advertisers:
To answer the original question:
Even if you have air-conditioning, dehumidifiers tend to be worthwhile if you have humidity issues. They definitely work, generally have a higher capacity than air-conditioning units, and are more efficient (i.e., use less energy for the same degree of dehumidification). They also tend to have controls/auto-switches to turn on/off at certain humidity levels (akin to a thermostat in heating or air-conditioning) – not many air-conditioning units have this function.
As others have already pointed out, your need for/the benefits from dehumidifiers vary with location (sometimes within the same building). Many people get by without a dehumidifier (or rely on air-conditioning with a dry function) – but few people living, say, at or around Victoria Peak would be prepared to surrender their dehumidifiers.
Please support our advertisers:
what about those dehumidifier packets you can buy at the local supermarkets? You tear off the top and leave in cupboards - meant to be good for months, so they say? Are they any good?
Please support our advertisers:
kar
19 yrs ago
We live on a boat and we have three dehums that we run continually. One in each bathroom and one in our storage room (which is on the same level as our engine room).
Please support our advertisers:
hortons,
those little packets hold just 450ml or 750ml of water. By contrast, a good electric dehumidifier extracts 25 litres or more of water per day. So you would need to use several dozen of those little packets each day to achieve the same result! (The little packets are really designed to be put in wardrobes or storage boxes, not open rooms.)
Please support our advertisers:
@: No, no contradiction. The evaporation process takes place within a closed system (two connected coils with a compressor and expansion valve in between). The air never has direct contact with the freon (check the diagram at the link that I posted - click through to the second or third page on air-conditioning).
Please support our advertisers:
> , you can get them in Wing On (definitely Sheung wan branch, maybe others). They're in the same ground floor room as the vacuum cleaners and kettles.
Please support our advertisers:
My other half has just bought a dehumidifier. It works a treat and pulls 16L over a couple of days out of the air. 2K from Fortress.
Air Cons do remove the moisture from the air, however its not their primary function, its more of a added bonus - apart from when it drips on you in the street from a great height...
I used a de-humidi in the UK when I was drying out new plasterwork. Worked well.
Please support our advertisers:
Get the dehumidfier. It works well and will save you time and money replacing paper valuables and re-washing mouldy clothes (if you wash clothes at home). They are indispensible. I canliterally walk into my flat and instantly know it mine's been running or not. And it's great for sleeping because the bedding usually feels damp without it. Just my experience:)
DD
Please support our advertisers:
>,
for some reason, the only ones that work for us are the pink ones with a picture of an elephant with rosy cheeks on them - and Wing On dept store is much cheaper than elsewhere for them. I don't know why, but only the 450ml ones seem to work - the 750ml ones don't, with us.
Please support our advertisers:
I wonder if one of those smaller ones at Wing On (for under $2K) would be sufficient for a 680 sq. ft. apartment? Also, does anyone know how efficient they are? My guess is that they'd be like a small a/c unit
Are they noisy?
Please support our advertisers:
weh
19 yrs ago
Interesting discussion but no one has yet explained humidity and relative humidity (RH). Humidity is a measure of the amount of water vapour in the air. RH is a measure of the amount of water vapour in the air compared with what the air CAN hold. Hot air can hold a lot more than cold air. A RH of 90% at 33 degrees means a lot more water in the air than a RH of 90% at 15 degrees C. Now, Cool that hot air down (with an air con) and the RH may stay the same but a lot of water is removed - yes to the drip tray under the aircon and down the proper outlets (if the air con is maintained well). Therefore an aircon DOES remove water AND cool hot air.
A dehumidifier only does one of those jobs and not as efficiently as an aircon WHEN THE AIR IS HOT. Running an aircon in winter is just a waste of money. It draws cold air over cold tubes and cannot have much effect on the air temp. Therefore it cannot have much effect on the RH. Why would anyone want to waste money (and power resources) doing that???????
There is a good argument for running a dehumidifier during spring but aircons should be much more efficient in summer. People who complain of high humidity despite running aircon in summer should look atw ays to reduce the amount of water getting into their rooms. Are windows left open?
Please support our advertisers:
I'm pretty sure A/C still works even when it's not cooling the air, because that's how I always used to defog the windows in my car. Just turn in the A/C and crank up the heat - you get nice warm air coming out, and defogged windows.
But that's a great post about Humidity contrasted to Relative Humidity, and it makes a lot of sense to me.
In the spring or winter, it would probably be enough to just close the windows
Please support our advertisers:
>,
no - never used them... you have to have had the foresight to have put your wardrobe near a power socket and to have drilled a hole in the back of the wardrobe big enough for a plug!
Please support our advertisers:
C
19 yrs ago
You can find them in Wing On Sheung Wan, they are called damp catchers (or something like that)
Please support our advertisers:
Does the dry function of split a/c do the same job as a stand alone dehumidifier? Which uses more electricity? Is it still worth getting a dehumidifier if we have split a/c in each room?
Please support our advertisers:
cd
19 yrs ago
Well, judging by our electricity bill in the warmer months when we have some aircons working, to this time of year when we just have 1 or 2 dehumdifiers working, I'd say the dehumdifiers are much cheaper to run.
Please support our advertisers:
You must be logged in to be able to reply.
Login now
Copy Link
Facebook
Gmail
Mail