# Passive cooling



## homesteadgirl (Feb 28, 2017)

Trying to prepare for the summer in the desert. What would you say is the easiest/cheapest methods for installing passive cooling? Links to good websites are welcome.


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## A Watchman (Sep 14, 2015)

Here ya go ... 25 Forum Posting Etiquette Tips


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## Smitty901 (Nov 16, 2012)

First it to break up sun light. Shade makes a big difference Second air flow movement of air. If you can get deeper in the ground you will find cooler temps.
You would be surprised a now much just camo netting alone will drop temps.


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## Slippy (Nov 14, 2013)

A Dog Trot style house (also known as Southern Vernacular Architecture) with a central breezeway is a tried and true form of passive solar used before Air Conditioning. I suggest using deep porches to keep direct sunlight from hitting the exterior walls and windows. A wrap around porch works best and orient the breezeway to take advantage of the prevailing winds. 

Since cooking in the kitchen and doing laundry make these two rooms the warmest, design the floorplan of the house so that the kitchen and laundry rooms are on one side of the "Trot" (Breezeway) and the bedrooms are on the other side.


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## Chipper (Dec 22, 2012)

Dig a hole and live under ground would be the cheapest.


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## dwight55 (Nov 9, 2012)

You might also look up the term "swamp cooler", . . . they are falling out of favor in many places, . . . but the do work if you live in a place where the humidity is pretty low, . . . which of course is normal in the desert in the summer months.

My first experience with one was in Big Spring, Texas, . . . went in to an electrical contractor's office for a meeting, . . . it was blazing outside, . . . super cool inside, . . . later asked one of his employees about the A/C, . . . he laughed and told me it was a swamp cooler.

Another thing is tall ceilings, . . . heat travels upward, . . . leaving cooler air below. That is one of the reasons the architecture of the South often incorporates 10 and 12 ft ceilings. We did that in our house in Ohio. . . . made a world of difference.

May God bless,
Dwight


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## OrneryOldBat (Feb 10, 2017)

Not passive, but if you go with the tall ceilings, breezeways, and porches - an attic fan is wonderful, especially if you've got a basement to pull extra cool air out of during the day. I grew up in TX without a/c and we were very comfortable.

Look at some of the designs people lived in before a/c in your area. Thick-walled adobe houses are cooler than stick houses in the summer. A house built around an atrium with a garden and fountain/pond can be defensive and comfortable in the heat.


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## sideKahr (Oct 15, 2014)

I attended a retreat where the living quarters were passively cooled. The place was built with two exterior block walls separated by an airspace that vented into the living space. It had been constructed by the Mennonites. The hollow walls connected with small tunnels or pipes radiating outward buried 4 feet or so underground. The tunnels drew in air from small louvered and screened enclosures in shaded locations, and was cooled as it moved into the house. I suppose it would only work if the ground temperature was considerably lower than the air temp. I've never seen plans for it but it really worked.

Just a quick comment on the swamp coolers, which are evaporative coolers. They are practical only where the water supply is cheap and abundant. They require maintenance to prevent mosquito and disease growth in the water (we've had legionaires disease around here). And hard water will quickly clog the evaporators.


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## RJAMES (Dec 23, 2016)

Home near me had screened air tubes to bring in cooler air. 3 or 4 inch tubing with a J on top turned to face down and screened. Takes the air down and into the bottom of the home windows open in central copula on top. Copula had insulation and could be shut off in winter. 24 to 30 inch thick walls they grow a lot of vines on the south side of the home on trellis as it heats up the plants get bigger an dive more shade. Die off and let sunlight/ heat hit the wall in the winter. 


I did not do the tubes but do very well without running AC as long as night time temps get down to 70-74. Straw bail walls are 24 inches with big porches all around as soon as night time temps drop we open the doors windows and get real good breezes , cools house down really well , trick is to close it up tight before it warms back up. We have ceiling fans in every room and a high ceiling in the great room. 

Another option I have seen that works well is a screened in sleeping porch. 

In a desert thermal mass is your friend. Use metal roofing , insulate the ceiling as much as you can , use a high ceiling and 12 feet or more deep porches . Vines to the south.


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## Smitty901 (Nov 16, 2012)

What I learned in the dessert. One it is not as devoid of life as it looks. There are nasty little bugs that want to eat you one bite at a time. Scorpions really do sting. That most desserts are not sand but clay. That clay is nasty when disturbed and worst when wet. Sand blown by high winds hurts. That both clay and sand can get in a zip lock bag. And other places it does not belong, and nothing you do can stops it. I learned that tents suck also.
That 130-140 degrees is hot I don't give a dam what the humidity is . Dry heat still sucks. That when it is less than 20% humidity at night and it drops to 70-80 degrees it is dam cold. I did learn that even at 130 degrees and 20% humidity you can live and function well if you drink water and pace your self. The lower humidity does help evaporate the moisture from your skin and cool you. I learned why in the midday heat every thing and everyone slows down. I heard a soldier explaining to his family what it was like. He said crank the over up to 140 degrees get in with a hair dryer close the door and turn the hair dryer on your face .
I learned these lessons on more than one trip.
If you want to get cool you have to block the sun if you can get the cover as high above you as you can. One layer that is solid that lets no light through with another above that by a couple feet works best. If the top layer is a camo net it works well. There is a reason hajji has light colored tents.


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## paraquack (Mar 1, 2013)

First off let me say howdy.


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## jagular (Feb 6, 2016)

I work in the architectural field and am on my way to licensure. An efficient passively heated/cooled house needs to be designed from the ground up. It must take into account orientation, sun, shade, mass, materiality, volumes, air flow, etc. to give the best performance above and/or below ground. This goes in-hand with any mechanical systems that might be used to supplement a comfortable living space. Anything done retroactively, to a modern commercial house, is just a band aide where none of the fore mentioned components work efficiently together. That is...without breaking the bank as these types of homes are typically built to a minimal standard. There are ways to mitigate some climate effects such as awnings at the correct angle to block summer sun but let winter sun in. 

This can get really scientific and there are specialists even within the architectural field that deal with these concepts. Energy modeling is an great way to experiment with design. 

You've probably considered this but if you are going for passive cooling in a desert environment, you should also be looking into passive heating. I live in the desert southwest and the other must considered for a house that performs all year round. Also, in the desert sw, we see 30-40 degree temperature swings which means you are going from passive cooling to passive heating, in terms of stored energy, within a 24 hour period. In short, there is no simple answer that will yield the best results but I applaud your inquiry and willingness to try and do something.


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## beavervallyranch (Mar 18, 2017)

I installed earth tubes in the floor and north wall of my solar greenhouse. The tubes are buried in the ground so you use cool earth to cool your air. I can pull 120 degree air off the peak through ducts into the tubes and the air returns in at 75. Google earth tubes


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## 8301 (Nov 29, 2014)

I was close to building a super energy efficient home before buying this place so I'd already done a lot of reading on the subject.

My current place is a 30 yr old farmhouse which I've added additional insulation to and the original owner planted 2 trees to help shade it in the Georgia summers. Still, I really wish I had been able to use thicker walls for more insulation and eves to control the sun for winter heating vs summer cooling. Lots of airflow for summer cooling now that I've added several screen doors. 

My compromise was a solar powered mini-split to supplement the wood stoves. The homes 4 ton AC unit was very inefficient but still available if ever needed.


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