Naturally decreasing humidity?


If you have a humid climate all year round, how would you decrease humidity in a house without using a dehumidifier? I know cactus take water from the air but I assume the effect is quite negliable. The same I guess for passive dehumidifiers.


We are doing a project in Kenya and the biggest discomfort is humidity in that region.

Oct 7, 16 1:30 pm

Cross ventilation and elevating the building off of the ground.  Stale air is the worst in a humid environment...  Look at some vernacular buildings in extreme humid climates... 

Oct 7, 16 2:04 pm  · 
Non Sequitur
Something something about orientation to prevailing winds.
Oct 7, 16 2:14 pm  · 

ad desiccants.  lots of silica gel.

Oct 7, 16 2:28 pm  · 

Earthen plasters will help modulate RH. I don't know of any passive system that will actually remove atmospheric moisture.  

Oct 7, 16 3:22 pm  · 
You'll need something to cool the air, leading to the moisture in the air to condense. Then you'll need something to heat the air back up to a temperature that is comfortable for your building.

In a hot climate the second part shouldn't be an issue, just mix the cold air with the warmer existing air. It's getting the existing hot, humid air to cool down that is the problem.

The plus side is when you do figure it out, you'll also have a source of water.
Oct 7, 16 3:40 pm  · 

High ceilings, operable windows above the interior doors, interior doors lined up to facilitate breeze flow-through the entire house, use of fireplace flues to aid in venting rooms, ceiling fans, extensive use of large trees and shrubs near the building for shade and evaporative cooling effect. Long porch along the south/west side to provide shade along that side as well.

Oct 7, 16 5:54 pm  · 
1  · 

I hate to be "that guy" but only a few of these suggestions are actually addressing what the OP asked ... how to decrease humidity. To decrease humidity you have to pull moisture out of the air. Allowing for breezes and moving air doesn't do this. Neither does providing for shade. They do make tolerating humid environments easier, but they aren't dehumidifying the air.

Also, evaporative cooling doesn't really work that well in a humid environment because the air already has a lot of moisture in it ... it works great in hot arid climates, but not hot humid ones. Plus, evaporative cooling adds moisture to the air, so it's actually doing the opposite of what the OP wants. 

Oct 7, 16 7:06 pm  · 

Unless you are storing artwork, humidity control isn't the end goal - that goal would be thermal comfort, So while the proposals above don't lower humidity, they certainly help make the space be more comfortable without an active environmental control system.

Oct 7, 16 7:21 pm  · 

Two other suggestions, on south and west windows that are in the path of the noon and afternoon sun, use Bahamian shutters that are hinged at the top to keep sun light out while letting air in and, if you have a metal roof, paint it white, rather than leaving it the silver bare metal - that makes a big difference.

The houses in Charleston, SC, and Key West, Florida, were influenced by the houses in the Caribbean, particularly, Barbados. The Audubon House in Key West is worth a detailed look on its own, both for the architecture and landscaping. It was designed by a sea captain. Go figure.  

Oct 9, 16 8:32 am  · 

Surprised no one mentioned thick walls for high thermal mass.

Oct 9, 16 10:55 am  · 
^ that's because it doesn't work for humid climates.

Using thermal mass to regulate heat in buildings is appropriate for hot arid climates where there is a large diurnal temperature swing. In hot humid climates there is not enough of a temperature swing to make the use of thermal mass effective.
Oct 9, 16 11:19 am  · 

What Everyday Intern said.  The only passive solutions for hot/humid environments are ventilation and shading, and as a result low mass construction is preferred.

Oct 9, 16 5:57 pm  · 

They use stepwells in India and asia, the water is evaporated and used to cool enclosed spaces.

Limit the amount of light coming in using smaller light thresholds, in Vietnam and several Asian countries a light material is used to cover the window to allow light to penetrate but reducing it.

I read that in the middle east they create "wind tunnels" to cool down buildings.

Oct 10, 16 8:26 am  · 

In the design of homes in the Charleston Battery they aligned the rectangular "single" homes with the small end facing the waterfront which allowed for ample side yards and gardens unusual for an urban area. The full-length, often two story porches, opened up to the garden. The idea was to get the breezes flowing not only through the house but alongside the houses and to the second and third rank of homes that were built behind them.

Oct 10, 16 10:40 am  · 

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