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.
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...
So what's your excuse now? Is Mercury out of retrograde? I personally blame the microchip in my vaccine. It's great for 5G but dang if that constant buzzing isn't annoying.
Good necro thread. That Everyday Intern guy was hot off some learning for the ARE on climate strategies as well as a Lstiburek seminar where during a portion we discussed HVAC, dehumidification, and the psychometric chart.
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 ·
·
JonathanLivingston
This is the closest answer here. Along these lines, I wonder if you could design a passive dehumidifier. I'm thinking something like a large air intake that directs incoming air down into a cold well in the ground where moisture condenses then a large tower where it can be heated and mixed with internal air before it enters the conditioned space.
Jul 27, 21 5:13 pm ·
·
JonathanLivingston
Maybe just a cold copper coil that circulates water into the ground, provides a condensing surfa
ce for air coming into space.
I suppose something along those lines would work, though the ones I've seen usually involve electricity to run a compressor and fans to push/pull air across the coils.
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.
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.
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.
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.
^ 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.
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.
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.
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.
People have explained very nicely above, yes, for a humid climate, we require an air circulation that would take out the moisture from the air, so the concept is to make the air in circulation, take the cold air in and let the hot air rise and get out from the operable ventilators (windows above the door level), Tress are helpful to make the air circulation.
Kindly add on this or make a discussion, it's great for everyone's knowledge.
Jul 27, 21 3:09 am ·
·
BabbleBeautiful
How do trees help with air circulation?
Jul 27, 21 7:50 pm ·
·
Volunteer
Transpiration, typically from the leaves, will cool the air in the immediate vicinity of the tree. The difference between the temperature of this airmass immediately around the tree and the airmass outside the tree boundary will create air movement by itself. Also the bare ground heats up significantly on a summer's day whether it be concrete, asphalt, or bare earth. The ground under a leafy tree does not heat up nearly as much. The air next to the bare ground is heated by the ground. The air next to the ground under the shady tree is not heated nearly as much. This also to a difference in localized air mass temperatures which also induces air movement.
Naturally decreasing humidity?
Hi
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.
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...
damn I was a wise one in my younger days.
Yeah, WTF happened to you?
don't know Chad... mercury must have been in retrograde back then.
So what's your excuse now? Is Mercury out of retrograde? I personally blame the microchip in my vaccine. It's great for 5G but dang if that constant buzzing isn't annoying.
I'm only at 4.3g.... damn canadian exchange rate.
Good necro thread. That Everyday Intern guy was hot off some learning for the ARE on climate strategies as well as a Lstiburek seminar where during a portion we discussed HVAC, dehumidification, and the psychometric chart.
ad desiccants. lots of silica gel.
Earthen plasters will help modulate RH. I don't know of any passive system that will actually remove atmospheric moisture.
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.
This is the closest answer here. Along these lines, I wonder if you could design a passive dehumidifier. I'm thinking something like a large air intake that directs incoming air down into a cold well in the ground where moisture condenses then a large tower where it can be heated and mixed with internal air before it enters the conditioned space.
Maybe just a cold copper coil that circulates water into the ground, provides a condensing surfa ce for air coming into space.
I suppose something along those lines would work, though the ones I've seen usually involve electricity to run a compressor and fans to push/pull air across the coils.
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.
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.
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.
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.
Surprised no one mentioned thick walls for high thermal mass.
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.
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.
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.
windcatchers
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.
People have explained very nicely above, yes, for a humid climate, we require an air circulation that would take out the moisture from the air, so the concept is to make the air in circulation, take the cold air in and let the hot air rise and get out from the operable ventilators (windows above the door level), Tress are helpful to make the air circulation.
Kindly add on this or make a discussion, it's great for everyone's knowledge.
How do trees help with air circulation?
Transpiration, typically from the leaves, will cool the air in the immediate vicinity of the tree. The difference between the temperature of this airmass immediately around the tree and the airmass outside the tree boundary will create air movement by itself. Also the bare ground heats up significantly on a summer's day whether it be concrete, asphalt, or bare earth. The ground under a leafy tree does not heat up nearly as much. The air next to the bare ground is heated by the ground. The air next to the ground under the shady tree is not heated nearly as much. This also to a difference in localized air mass temperatures which also induces air movement.
Sounds pretty good. In addition, high-quality ventilation is more useful than dehumidifiers and heaters, which also make the air drier.
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