Best running tips for dehumidifiers

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AklBen

102 posts

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#272537 30-Jun-2020 13:06

It's been a week of rain in Auckland and the house is starting to feel a bit damp. Dehumidifier it is until we do more major work on the place solving issues properly.

Ideally we'd be wanting to run the dehumidifier in two spots, the lounge/dining area and also in our bedroom which has a connected ensuite and wardrobe: the ensuite is getting mould on the ceiling and a damp smell in our clothes in the wardrobe.

What have people found the best? I don't really want to run it 24 hours a day, but do people run it for 4-8 hours in their lounge and then move it around or what?

Thanks!

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#2515034 30-Jun-2020 13:14

Serious question: have you tried opening the windows? When it's cold outside the humidity is low, so if there's no rain actively coming in the windows opening them reduces your humidity.

wellygary

8328 posts

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#2515043 30-Jun-2020 13:46

bedroom which has a connected ensuite and wardrobe: the ensuite is getting mould on the ceiling and a damp smell in our clothes in the wardrobe.

Look at upgrading or installing a fan/opening the windows more in the bathroom, Its obviously the source of the moisture in the two adjoining spaces,

Running a Dehumidifier is an expensive wats to "band aid" a moisture problem, tracking down and eliminating the source of the moisture is the best option...

alasta

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#2515061 30-Jun-2020 13:54

Run your dehumidifier when you have heating on. Heaters work better with dry air, and dehumidifiers work better with warm air.

Hammerer

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#2515107 30-Jun-2020 14:11

alasta:

Run your dehumidifier when you have heating on. Heaters work better with dry air, and dehumidifiers work better with warm air.

This advice depends upon which type of dehumidifier you use:
Compressor dehumidifiers work better with warm air.
Dessicant dehumidifiers work much the same with cold-to-freezing or warm air.

We run our dessicant dehumidifier all day in the hallway outside our bathrooms and bedrooms. It works great except where bedroom doors are closed at night.

We move it into our living areas during a rainy period if we are drying/airing clothes we can't tumble dry.

Nate001

645 posts

Ultimate Geek

#2515112 30-Jun-2020 14:15

We generally open windows on nice days to get airflow. Close them in the afternoon/when we get home and start the dehumidifier and set to 55 RH and let it do its thing.

Don't forget everything in your house holds moisture so its a long term activity to get the moisture out. Your clothes, carpet, walls, furniture all hold moisture.

If possible shut off room, such as in your wardrobe, and run the unit in a smaller volume. Try get the RH down <50% to get things under control.

mudguard

2119 posts

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#2515117 30-Jun-2020 14:26

I live in Auckland too and leave the bathroom windows open virtually all the time. It will stay damp otherwise as the fan is tiny and poorly placed. But an open window deals to it. Fortunately they're on a second floor so the security risk is low.

I agree the dampness needs to be dealt with rather than pulled out by dehumidifier. I sleep with the window open nearly all year round too.

Blurtie

468 posts

Ultimate Geek

#2515120 30-Jun-2020 14:30

We turn it off overnight - mainly due to noise. We have a timer function to turn it on in the morning, so it'll usually run for about 16-18 hours a day. Combined with the heat pump we have in the adjacent lounge and keeping that door between the two spaces open, it helps to keep that partof our house between 18-21 degrees, so I do use it partly as a heater as well.. Last i checked, those things hardly use any power, but i guess it all adds up if you're using them constantly like I do.

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neb

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#2515121 30-Jun-2020 14:32

AklBen:
What have people found the best? I don't really want to run it 24 hours a day, but do people run it for 4-8 hours in their lounge and then move it around or what?

A dehumidifier works like a slow-acting sponge, it sucks moisture out of the air where it is over a period of several days, with the moisture slowly migrating towards the drier area over time until the level is fairly uniform over an enclosed space. So you need to run it continuously, and you need to keep it enclosed to prevent more moisture from migrating in.

timmmay

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#2515125 30-Jun-2020 14:39

mudguard:

But an open window deals to it. Fortunately they're on a second floor so the security risk is low.

A friend of my wife had people break into the second floor. Twice. The intruders bought a ladder with them.

mudguard

2119 posts

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#2515133 30-Jun-2020 15:01

timmmay:

mudguard:

But an open window deals to it. Fortunately they're on a second floor so the security risk is low.

A friend of my wife had people break into the second floor. Twice. The intruders bought a ladder with them.

I should add I've been working from home since February!

Blurtie

468 posts

Ultimate Geek

#2515136 30-Jun-2020 15:07

On a somewhat related note and apologies for the hijack, has anyone used their heat pump on 'dry' mode instead of using a dehumidifier? is it the same? Any pros/cons would be appreciated.

AklBen

102 posts

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#2515143 30-Jun-2020 15:12

"Serious question: have you tried opening the windows? When it's cold outside the humidity is low, so if there's no rain actively coming in the windows opening them reduces your humidity."

Yes, I am a big fan of opening the windows but we aren't home between 730am and 6pm during the week, and as it has been raining a lot you cannot always have windows open let alone leaving a window open which is visible from the street. Depending on the weather, unfortunately over the last two weeks I'd say the windows have only been opened a few times on the weekend.

"Look at upgrading or installing a fan/opening the windows more in the bathroom, Its obviously the source of the moisture in the two adjoining spaces,"

Yes, I will be getting the fan upgraded in the bathroom and getting a showerdome too.

Overall as I stated in the OP I am aware this is a band-aid. I cannot go all in now with other solutions as we're staging certain things that are more important (like a new roof).

Thanks for the other replies!

gzt

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#2515144 30-Jun-2020 15:14

Blurtie: On a somewhat related note and apologies for the hijack, has anyone used their heat pump on 'dry' mode instead of using a dehumidifier? is it the same? Any pros/cons would be appreciated.

Dehumidify setting on a heat pump is usually designed for warm weather. The function is sometimes referred to as reverse cycle. Makes cold inside I think.

In contrast, a standalone dehumidifier releases heat inside the house.

timmmay

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#2515150 30-Jun-2020 15:26

gzt:
Blurtie: On a somewhat related note and apologies for the hijack, has anyone used their heat pump on 'dry' mode instead of using a dehumidifier? is it the same? Any pros/cons would be appreciated.

Dehumidify setting on a heat pump is usually designed for warm weather. The function is sometimes referred to as reverse cycle. Makes cold inside I think.

In contrast, a standalone dehumidifier releases heat inside the house.

Some units cycle between cooling (to dehymidify) and heating to maintain the current temperature.

Nate001

645 posts

Ultimate Geek

#2515158 30-Jun-2020 15:35

AklBen:

"Serious question: have you tried opening the windows? When it's cold outside the humidity is low, so if there's no rain actively coming in the windows opening them reduces your humidity."

Yes, I am a big fan of opening the windows but we aren't home between 730am and 6pm during the week, and as it has been raining a lot you cannot always have windows open let alone leaving a window open which is visible from the street. Depending on the weather, unfortunately over the last two weeks I'd say the windows have only been opened a few times on the weekend.

Depending on your situation, the outside air on a rainy day could be drier...

Take for example your humid house, 21c at 80% RH. That equals 15 grams/m3 of water.

Outside raining might be 12c at 80% RH = 9 grams/m3 of water.

If you let that colder air in, let it warm up it contains the same absolute moisture but at 21c it is now 50% RH.

Have a play with this calculator yourself https://planetcalc.com/2167/ Make sure you set the pressure to something realistic such as 1010 hPa.

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