Dehumidifiers, are they worth running? How big?

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TeaLeaf

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Topic # 229201 12-Feb-2018 14:31

We are currently between homes and renting. And In Auckland its damn humid. I use to live in Qld so Im use to it but mould is less of an issue there due to sunlight. 27 feels hot with high humidity as well (although Im use to 40+ with 99% in qld).

Ive never bought one but the Mrs wants one.

For a bedroom flat what size is needed?

Does that mean you have to keep the windows shut all the time, ie no cooling?

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Reply # 1955772 12-Feb-2018 14:45

My Mitsubishi Oasis has an 'air purifier' mode, which essentially runs the fan and cycles air through the filter with the dehumidifying function disabled. So when it's hot I leave the front door open with the machine on air purifying to circulate the fresh air, and otherwise I run the machine on its normal operating modes.

TeaLeaf

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Reply # 1955817 12-Feb-2018 15:58

Thats exactly what Im after, I wonder if most have that kind of mode.

What size is yours?

alasta

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Reply # 1955861 12-Feb-2018 16:13

I think it's the VX16 - still a current model. For what it's worth I've had mine for six years and never had any problems even with daily usage. The filter needs to be washed every three months and replaced every two years but it's only about $45 to replace and no other maintenance is required.

timmmay

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Reply # 1955872 12-Feb-2018 16:20

TeaLeaf:

Does that mean you have to keep the windows shut all the time, ie no cooling?

Pretty much, you can't dehumify the world. You could try to get a portable air conditioner. You might be better off opening the windows and having a fan blow hot air out.

alasta:

My Mitsubishi Oasis has an 'air purifier' mode, which essentially runs the fan and cycles air through the filter with the dehumidifying function disabled. So when it's hot I leave the front door open with the machine on air purifying to circulate the fresh air, and otherwise I run the machine on its normal operating modes.

Wouldn't this make the room warmer? Given warm air can carry more moisture it could make things more humid.

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TeaLeaf

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Reply # 1955889 12-Feb-2018 16:42

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timmmay:

Wouldn't this make the room warmer? Given warm air can carry more moisture it could make things more humid.

That was my concern, but what else can you do given you want fresh air and the only way without air con is to have a breeze via open windows etc.

So its catch 22, yes it makes things more humid but thats the idea of a dehumidifier.

Having lived in Air Con 24/7 for 15 years of my life I definitely dont like air con, but I do like being cool.

The ultimate would be to have air con, dehumidifier stuck into a wall to let fresh air in. But not buying this pad so not doing that :-)

alasta

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Reply # 1955893 12-Feb-2018 16:52

I have always been told that opening doors/windows reduces dampness even though the outside air is more humid than the inside air. I don't really understand the science so I've just taken that advice.

timmmay

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Reply # 1955974 12-Feb-2018 20:02

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All a filter will do is remove dust, and add heat. Open a window, point a fan out, or get an air conditioner IMHO.

alasta:

I have always been told that opening doors/windows reduces dampness even though the outside air is more humid than the inside air. I don't really understand the science so I've just taken that advice.

Why would the outside air be more humid? People and cooking produce humidity. Heat and humidity will generally come to equilibrium unless there's something else going on.

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jonathan18

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Reply # 1955982 12-Feb-2018 20:34

timmmay:
All a filter will do is remove dust, and add heat. Open a window, point a fan out, or get an air conditioner IMHO.

alasta:

I have always been told that opening doors/windows reduces dampness even though the outside air is more humid than the inside air. I don't really understand the science so I've just taken that advice.

Why would the outside air be more humid? People and cooking produce humidity. Heat and humidity will generally come to equilibrium unless there's something else going on.

That’s not my experience from my highly scientific (joke) examination of the humidity readings on our indoor/outdoor thermometer. It’s been crazy humid the last few days, both inside and out, but never have I seen it more humid inside than out. I mean when it’s raining the humidity outside is registering well into the 90s, whereas it was damn high inside (as we had all doors and windows open) but only in the 70s. I’d hate to see what a house with 95% humidity inside was like...

alasta

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Reply # 1956008 12-Feb-2018 20:42

jonathan18:
timmmay:

All a filter will do is remove dust, and add heat. Open a window, point a fan out, or get an air conditioner IMHO.

Why would the outside air be more humid? People and cooking produce humidity. Heat and humidity will generally come to equilibrium unless there's something else going on.

That’s not my experience from my highly scientific (joke) examination of the humidity readings on our indoor/outdoor thermometer. It’s been crazy humid the last few days, both inside and out, but never have I seen it more humid inside than out. I mean when it’s raining the humidity outside is registering well into the 90s, whereas it was damn high inside (as we had all doors and windows open) but only in the 70s. I’d hate to see what a house with 95% humidity inside was like...

Yeah, the humidity inside my place sits around 60-70%, whereas weather reports usually indicate upwards of 70% outside in Wellington.

As for the filter I figure it might help a bit with my hayfever, and it must produce bugger all heat or it would catch fire given the material it's made of.

tdgeek

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Reply # 1956018 12-Feb-2018 20:54

jonathan18:
timmmay:

All a filter will do is remove dust, and add heat. Open a window, point a fan out, or get an air conditioner IMHO.

alasta:

I have always been told that opening doors/windows reduces dampness even though the outside air is more humid than the inside air. I don't really understand the science so I've just taken that advice.

Why would the outside air be more humid? People and cooking produce humidity. Heat and humidity will generally come to equilibrium unless there's something else going on.

That’s not my experience from my highly scientific (joke) examination of the humidity readings on our indoor/outdoor thermometer. It’s been crazy humid the last few days, both inside and out, but never have I seen it more humid inside than out. I mean when it’s raining the humidity outside is registering well into the 90s, whereas it was damn high inside (as we had all doors and windows open) but only in the 70s. I’d hate to see what a house with 95% humidity inside was like...

Rain is 100% humidity. I read on Stuff its been really humid in AKL, but its not the norm, so I'd live with it. Im in ChCh where its not often humid, but Ive spent time in new Orleans where you can feel the warm wet air, like a warm mist. AKL's current time is not normal, neither is snow, hail, 39C etc, just let it pass as best you can, I cant see the point buying an asset for a rare event, aside from a snow shovel.

mdav056

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Reply # 1956040 12-Feb-2018 21:49

I run an ancient (>10 years) deLonghi DS 105, a condensing dehumidifier (the best sort) and it's been running continuously for many years under my house. It's pretty essential down here. The best aspect of this is that you can attach the water catcher to some plumbing, and I sit it next to a sink and never have to worry about emptying it (great when you're on holiday). Only drawback -- it's bloody heavy!

gml

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Reply # 1956044 12-Feb-2018 22:04

When we were renting in Auckland, we got a portable air con unit, and had a "cat door" sized hole cut in the dining room window, and poked the portable exhaust out that. (We did have permission from the Landlord).

During the day whilst we were at work we set the AirCon to dehumidify, then when we got home we opened all the windows up. If it was particularly unbearable, we'd close up the house and run the air con. During the night we would close everything up again and usually run the unit in cooling.

The reason for locating in the dining room was simply due to noise - in a portable air con unit, the noisy parts are all inside the house.

We used to use a dehumifier, but the portable air con was worth it simply because of it's ability to cool the house. (During winter we used it to help heat the house as well.)

Aredwood

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Reply # 1956077 13-Feb-2018 00:22

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@TeaLeaf Dehumidifiers are far better during winter. As the temp gain from running a dehumidifier helps to offset your heating costs. (both from waste heat, and due to the latent heat of the condensed water). And you will also have the indoor temp rise due to solar gain to contend with as well.

Just get a fan or an aircon system as already mentioned.

And yes, I hate this Auckland humidity as well. Have had to resort to sitting in the van with the engine running and the aircon going a few times. Did that today, and there was a continuous trickle of water coming out of the condensate drain pipe. Which shows how crazy humid it was.

Would like to get aircon installed in my house, But have had to abandon that idea. As would have to get units moved again later due to future renovations.

Shindig

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Reply # 1956165 13-Feb-2018 09:30

I'm tempted to get a couple of oscillating fans, have just have the air moving around the lounge and dining room.

The little things make the biggest difference.

TeaLeaf

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Reply # 1956372 13-Feb-2018 14:43

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Air Con isnt really needed in NZ imo outside the 40 degrees days in Canterbury. It does however take away the feeling of humidity.

It feels hot in Auckland because of the humidity. 27 is not hot. If your house is full of moisture it feels hot because not only are you warm but you are dank. Get rid of the humidity and that 27 day feels more like 22, room temperature.

In saying that, I enjoy 22 and enjoy Air Con, I just know its not healthy 24/7. Very nearly bought a portable air con too. But once we hit march the temps drop but the humidity doesnt.

The real problem is how do you get the humidity low whist getting fresh air.

A lot of the humidity isnt in the air its trapped in your mattress, your couch, your clothes etc etc. Thats why it takes so long initially to get it to a human acceptable state 40-60%. I think the idea then is to air the house out then run the dehumidifier.

Anyway we ended up with the Mitsubishi 22l Recommended. I like that you can run it in winter with the technology inside, unlike old dehumidifiers with anything below 18degrees you are starting to waste your time. I also like that it has a hose which can be used instead of the jug.

I looked at last years monthly chars, one day hit just above 70%, Id say 90% of days were above 80% and 15% in the 90s, that is one humid country.

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