Dehumidifiers and air purifiers

Life Technology
1

What is the best brand of dehumidifier in Taiwan?
It should have an air cleaner function too.
Best value for money?

2

I have a Westinghouse that works pretty well. I know dehumidifiers seem a little pricey, but I would advise against buying a used one. I bought a used one and it lasted about a week. I friend of mine got a used one and it melted into the floor when he left it running.

The major brands make two types, A or B. The store will recommend which one to get depending on the area you live in.

As my doctor told me, if you are allergic to mold like I am, the first thing you want to get is a dehumidifier. A dehumidifier, however, is not an air filter. I would rely on a separate HEPA air filter for that. Hope this helps.

3

There’s somethingnot quite right about the air in our room. It’s a bit to ‘stuffy’ or something, but doesn’t really seem humid either. AC on high is OK, but I don’t want that anymore.

So anyone got experience with dehumidifiers or air purifiers? What do you think would be the best to try?

Brian

4

I haven’t tried an air purifier yet, but I was quite happy when I had a dehumidifier. My house at the time would get extremely humid, yet still be cool. Water would condense at the bottom of the doors on the refrigerator.

I would probably use a small fan and a hepa air purifier. See if you can borrow one and then try it out as they are expensive.

Okami

5

The problem with dehumidifiers in Taiwan is the constant high humidity. Buying one is a waste of money unless your apartment is very well sealed off from drafts or other places air can flow in and out. Nearly every apartment I have lived in is not “air tight.” Usually, the laundry area opens to the air and the doors and windows never seat properly; trying to dry the air is like trying to dry the air of the entire city – a losing battle.

6

Our dehumidifier works fine. The only complaint is it puts hot air into the room. Dehumidifier + AC are a good combo!

7

[quote]Dehumidifier + AC are a good combo!
[/quote] = $$$$

8

So a dehumidifier’s no good with the windows open then? I think maybe the problem is the air doesn’t circulate well. Anyone tried an air purifier? Any other ideas?

Brian

9

An air purifier wouldn’t change the humidity at all. An air purifier just filters out the particulate matter in the air (which is mostly tiny pieces of carbon soot).

As for a dehumidier, it would definitely make the room drier as long as the windows are sealed and the doors are closed, but it will also heat up the room unless you turn on the a/c every time you turn on the dehumidifier. I measured the air coming out of my dehumidifier and it was 40 degrees! The reason why a dehumidifier produces hot air is because a dehumidifier is actually the same as an air conditioner except that the whole machine is inside the house instead of having half inside and half outside. A dehumidifier cools down the air and then the water vapor in the air condenses because air at a lower temperature can’t hold as much humidity (which is the same reason why things that you take out of a refrigerator become wet right away).

For example, look at this chart of “absolute humidity” (which is the amount of water vapor in the air) compared to temperature. If the relative humidity is 90% (like it usually is in Taiwan), then the absolute humidity at 30 degrees is 32% more than it is at 25 degrees! (27.3 g/m3 compared to only 20.7 g/m3).

But getting back to the topic of dehumidifiers: Since the whole dehumidifier is inside the house (instead of half inside and half outside like an air conditioner), this means that after a dehumidifier cools down the air, then it heats the air back up when the air passes through the coils at the back of the unit. But the air heats up to be much hotter than it was originally because the compressor generates a lot of heat. (The compressor is composed of a piston inside a cylinder, much like a piston in an internal combustion engine except that there aren’t any spark plugs or valves.)

If you just turned on the a/c and not the dehumidifier, then the air would also get drier because the cooler the air is, the less humidity it can hold. But since the relative humidity in Taiwan is so high, an a/c plus a dehumidifier would dry out the air much more than an a/c by itself.

10

Bri, we’ve been using dehumidifiers and air purifiers for years. I don’t find the dehumidifier heats up the room that much. Just get a smaller one if you’re only concerned about one room. Or just open all the room doors and leave the dehumidifier in a central place. That’s usually what we do and it works quite well to dry out everything. In fact for general dehumidifying I find the dehumidifier works better than the aircon.

As for air filters we’ve been using Honeywell air purifiers with Hepa filters for about 4 years. They really help to take odors out of the air as well as suck up dust and cat hair. You should see the charcoal pre-filters after just a few months. :shock: On bad air days I close the windows and crank up the air filters for an hour or so on high and then leave them on low the rest of the time. If I step out and in again I can smell the difference in the air quality.

Sogo sells the Honeywells as does B&Q. Often there are sales - buy a larger one and get a smaller one for free. Given the design of your home, you should have one in the living room and a smaller one upstairs in the bedroom.

If you have any more questions, give me a call.

11

I use a HEPA filter because of my allergies which are really bad during the winter with all the dampness and mold growth. I have thought about getting a dehumidifier for this winter to slow down the mold although my current apartment seems much drier than my previous one. I have one large HEPA filter Honeywell in my bedroom which is open to the rest of the apartment and run my air conditioners in the other two major rooms to do some minor filtering. I also have small HEPA filter purifiers in my bathroom and kitchen that I bouht at B&Q. They have a night light on them and plug directly into the wall which can be a pain if you don’t have a lot of free plugs in your place, but they do a great job of keeping mold and odors down.

12

There is better technology out there then HEPA filters. And Honeywell purifiers pull alot of electricity. I’ve been using a new kind of air purifier for a year and have found a lot of my allergy problems have disappeared completely as well as any bad smells and stuffy air. Although not as cheap as a Honeywell it has solved all the problems. You need to look for a purifier that produces O3 as well as negative ion generation. If you need more info send me an email.

Dehumidifier’s have really only one purpose, to take the dampness out of the air.

13

[quote]You need to look for a purifier that produces O3[/quote]Are you sure about this ? I thought ozone is something you DON’T want inside ?

14

Thanks for all your replies. I think I’ll try an air purifier of some kind or other.

Brian

15

JeffG mentioned ionisers. By negatively ionising the air, they make the minute particles cling to surfaces. I can testify to this. Around a good ioniser, there will be an area of greasy dirt, and the walls of the room itself may need to be cleaned more often. Better that than breathing all the stuff in, surely.

Some of the more expensive ionisers sold in the UK have built-in fans and HEPA filters, so they circulate the air, cleaning it more rapidly and spreading the cleaned air, and they trap the dirt in the filter, saving you from that extra cleaning, presumably.

In addition to the air-cleaning, breathing negatively-ionised air is supposed to make you feel more relaxed and be able to concentrate better. We used to have one in the car that plugged into the cigarette lighter. It seemed to make a difference, but that might just have been a placebo effect.

JeffG also mentioned O3. Quick Google searches turned up this report by a physician;
geocities.com/Athens/Aegean/ … one99.html

and this commercially manufactured product;
ozonox.com/ozone_air_purifier_ozonator.htm

I know nothing about ozone but that the ‘invigorating’ smell at the seaside which is commonly held to be the smell of ozone is, in fact, the smell of rotting seaweed. Ozone itself is odourless.

16

Joesax,

My purifier has a fan which blows the negatively charged ions out into our apartment, I have never had greasy dirt stuck to anything.

And as to ozone’s healthful effects - ozone has been studied for years and research shows low levels of ozone to be greatly beneficial. See the following websites and article below for more info:

ozonio.com.br/bacteria.htm

appliedozone.com/references.html

trio3.com/moldsFungus.htm

fda.gov/OHRMS/Dockets/98fr/062601a.htm

aggie-horticulture.tamu.edu/exte … dec01/rrar
t1.html

ers.usda.gov/publications/ag … AO252C.PDF

sciencedaily.com/releases/19 … 051639.htm

Also see this article:

Much-maligned ozone can rid your home or office of modern pollution that can be more dangerous than outside air.

By Ron Rendleman

Most folks know ozone by name, especially since the upper atmosphere

17

[quote=“joesax”]In addition to the air-cleaning, breathing negatively-ionised air is supposed to make you feel more relaxed and be able to concentrate better. We used to have one in the car that plugged into the cigarette lighter. It seemed to make a difference, but that might just have been a placebo effect.

JeffG also mentioned O3. Quick Google searches turned up this report by a physician;
geocities.com/Athens/Aegean/ … one99.html

and this commercially manufactured product;
ozonox.com/ozone_air_purifier_ozonator.htm

I know nothing about ozone but that the ‘invigorating’ smell at the seaside which is commonly held to be the smell of ozone is, in fact, the smell of rotting seaweed. Ozone itself is odourless.[/quote]
I have never yet heard anyone try to tell me that the seaside smell is “ozone”. Rotting seaweed, yes; ozone, nope.

All I know is what I learned in chemistry classes, which is that ozone is a highly reactive molecule that damages your skin, eyes, throat, and lungs, among other parts – in short, any and all tissue exposed to it. Maybe the ionizers help to precipitate particles out of dirty air, but exposing yourself to the ozone that they produce is right up there with licking exposed electrical wiring.

The AV2500 ozone generator (commercial site you linked to) kills bacteria and mold, eh? I guess the manufacturer didn’t want to mention that it also kills you.

18

Sure, I don’t really know anything about it. Actually I didn’t have time to thoroughly read the physician’s article but it seemed to weigh up the opinions or evidence on both sides.

I thought ionizers and ozone producers were separate things. Negatively charged air isn’t the same as ozone is it?

I’ve owned ionizers but they didn’t say anything about ozone on them.

19

[quote=“JeffG”]Joesax,

My purifier has a fan which blows the negatively charged ions out into our apartment, I have never had greasy dirt stuck to anything.[/quote]

Does it have some kind of filter inside? I guess that could trap the dirt. The ionizers my family and I have had have been the cheaper variety without a fan. As I said, there’s a dark patch of dirt around them and then the walls and surfaces in that room tend to get a bit grimier as well. I see that as a positive thing - that’s so much dirt you’re not breathing in.

I repeat that I know nothing about ozone producers. Your post was the first I’d heard of them.

20

I thought ionizers and ozone producers were separate things. Negatively charged air isn’t the same as ozone is it?

I’ve owned ionizers but they didn’t say anything about ozone on them.[/quote]
My ex-girlfriend has several of them in her apartment, and uses them all the time. Hers are “ionic air cleaners” by Sharper Image, which is just marketdroidspeak for “ozone generators” in their case.

I tried to get her to quit using them – hey, it’s her life, but I’d like for her to have a long and healthy one – but she insisted on keeping them. Whenever I stayed at her place, if I started coughing and got a sore throat, it was invariably the case that she’d left the bedroom ionizer on by accident. (Well, except the time that it was strep, but we knew that in advance.)

Maybe other models are different, but you can smell ozone, so if you don’t know for sure, just turn yours on, stand next to it, and sniff. The ozone smells like there’s a thunderstorm brewing – kinda “fresh” and “sharp”. I’m not sure what else they could “negatively charge”; they’re limited to O2, N2, and Ar, which limits them to ozone and a few oxides of nitrogen, any of which are harmful.

If you want to use one of these things, I would recommend turning it off when you’re at home – and don’t use it around pets.