Nature's air conditioning

Home Inspector with Charles Buell Inspections Inc.


Grape shadeHow long have we been building houses?  A lot longer than we have been air conditioning houses.

Well we have certainly done things to keep warmer and dryer for thousands if not 100’s of thousands of years–but we have also done things to keep them cooler as well.

As a designer/builder for most of my adult working life, I have marveled at how ignorant we are of how to accomplish keeping warm, dry and cool.

We now have air conditioning systems that allow us to live in places where not too long ago it would have been considered uninhabitable–or at least inhospitable.

We have long had the knowledge to mitigate the use of air conditioning to some degree and yet we simply choose to turn down the knob on the thermostat.

Today I just want to talk about a few “passive” things that can be done to greatly decrease the use of actual mechanical air conditioners.

First and most important is house design and orientation. Obviously if we build a house and make all the south facing walls floor-to-ceiling glass, with no roof overhangs, we can expect to find ourselves inside a solar heated oven. Just providing a roof overhang to prevent the sun from hitting the windows directly can go a long way to turn the oven down a bit. By eliminating ground and other surfaces that might reflect the sun’s rays into the home can also be an improvement.


Living in the shade

Even these Native Americans made an attempt at basic principles

Of course reducing the amount of glass itself will make the most difference because then the walls themselves can be better insulated. This brings us to the huge topic of insulation in general. There is nothing like highly effective insulation in the walls and ceilings to keep the heat out of the house. This is not as simple as it may seem because heat is always attempting to move to cold and make balance. When it is 95 degrees outside, all that hot air is just hungry to gobble up our pathetic little bubble of coolness. So our air conditioners have to work their butts off to maintain that bubble of coolness.

While today I do not want to go into how I think houses should be built to eliminate the need for air conditioners altogether in many areas, I want to talk about ways we can deal with adverse conditions in our older homes in passive ways. While these things will not reduce your need for air conditioning in some areas it may greatly reduce the amount they may have to run. It may mean in some hot humid areas you might have to add a dehumidifier to make up for what the AC used to do.

The short story in all of this is to insulate your house as much as practical and use good air sealing type insulation–anything longer and we are into the full fledged novel.

One of the most important things you can do, if you live in an area where the nighttime temperature drops even 20 degrees between daytime and nighttime, is to change the air in the home and lower the thermal loading that has built up in the home during the day. The house is then closed up during the day to keep the nighttime cooling in and then the process simply repeats itself. In an average size house, even a simple window fan in a window on one side of the house and a window open on the opposite side of the house can accomplish this goal.

I cannot stress the importance of roof overhangs to keep the sun out, but in older homes that is not likely going to be possible.

In my own house, built in the early 30’s, the overhangs are insufficient to keep the south facing windows from overheating the house in the summer. So a simple thing I have done is to shade the windows with a grape arbor–the one plant now creates shading of most of my south facing windows and makes an amazing difference, and of course provides grapes in the fall.

grape shade

While we certainly do not get as hot as lots of areas of the country, my house certainly never needs any mechanical air conditioning. The attic has a ton of cellulose fiber insulation, the walls have minimal insulation limited by the 2×4 wall thickness, and we put a fan in an east window at night and open up a west window–on those occasional really hot days.

Before the days of the grape arbor, we use to have to do the fan approach a lot more.

If you have a house with a basement, you can open up a basement window (as the path to the upper fan in the window) and get the benefit of the cooler basement to improve the cooling of the interior space during the nighttime. Accessing the constant ground temperature is another thing that can have a huge impact on minimizing the mechanical cooling needs of the home.

A huge number of homes across America could benefit from this passive approach to improving house comfort and energy efficiency.

Charles Buell, Real Estate Inspections in Seattle

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Comments (19)

Kristin Johnston - REALTOR®
RE/MAX Platinum - Waukesha, WI
Giving Back With Each Home Sold!

I reinsulated my home and rental units within the last few key!

Jul 22, 2017 07:20 AM
Charles Buell

It does make a difference

Jul 22, 2017 06:05 PM
Eugene Kanciar
EKAN Home Inspection - West Vancouver, BC
Our Experience, Your Peace-of-Mind

Charles, I recall visiting Frank Lloyd Wright's winter residence in Scottsdale. It had many key features to keep it cool in the Arizona sun.

One issue that stood out to me was that Frank paid attention to the prevailing winds and constructed a shallow pool in front of the house which was upstream of the wind. As a result the hot wind would blow across the pond, get cooled off by the water surface, and then lo and behold this tempered air would blow into the house. A brilliant example of using evaporative cooling. 

By the way, Frank picked up the parcel of land for next to nothing because there was no water. Then he drilled a well to supply all his needs, including the pond. I am sure that Frank had investigated for subsurface water before the purchase, when all his contemporaries scoffed at the idea of finding water on a hillside. 

A unique individual and so ahead of his time. 


Jul 22, 2017 07:40 AM
Charles Buell

Hi Eugene, he really did do some interesting stuff.

Jul 22, 2017 06:05 PM
Jeff Dowler, CRS
eXp Realty of California, Inc. - Carlsbad, CA
The Southern California Relocation Dude


This was certainly an educational post  with some great ideas instead of AC. Love the idea of the grape arbor, or something similar.  There are plenty of west facing homes here with massive windows to take in the views, and to heat up the house!!


Jul 22, 2017 08:01 AM
Charles Buell

There are lots of simple things that could be done to greatly reduce the need for AC

Jul 22, 2017 06:06 PM
Joe Pryor
The Virtual Real Estate Team - Oklahoma City, OK
REALTOR® - Oklahoma Investment Properties

We live in a home from the 1960s that has the original pella windows. In three weeks they get replaced with new ones and we can't wait, especially since it reached 103 degrees today.

Jul 22, 2017 01:19 PM
Charles Buell

60's Pella, wow, those do go back a ways.

Jul 22, 2017 06:06 PM
Belinda Spillman
Aspen Lane Real Estate Colorful Colorado - Aurora, CO
Colorado Living!

There are many steps we can take to keep our homes cool in the summer without cranking up the A/C.  I love your photo of the cliff dwellings.

Jul 22, 2017 01:38 PM
Charles Buell

Yes, probably not too far from you (relatively  )

Jul 22, 2017 06:07 PM
Kathy Streib
Cypress, TX
Home Stager/Redesign

Charles- I'm not sure if this fits in with your example, but growing up in Houston our house had an attic fan. When it was hot, I can remember how cool it was when we had the front door open (it had a screen door) and the attic fan running. 

Living in Florida, we quickly learned to avoid houses with a backyard facing west unless there was sufficient shading from trees. 

Jul 22, 2017 03:48 PM
Charles Buell

Any really hot climate that gets cooler at night can benefit from the type of whole house fan you speak of

Jul 22, 2017 06:08 PM
Kathy Streib
Cypress, TX
Home Stager/Redesign

                          Thank you Charles Buell 

Jul 22, 2017 04:58 PM
Anna Banana Kruchten CRS, Phoenix Broker
HomeSmart Real Estate BR030809000 - Phoenix, AZ

Charles really good information!  We do all we can in PHX to be as energy efficient as possible. It makes a BIG difference.

Jul 22, 2017 05:02 PM
Charles Buell

I have a feeling Phoenix would be interesting with no AC

Jul 22, 2017 06:09 PM
Gary L. Waters Broker Associate, Bucci Realty
Bucci Realty, Inc. - Melbourne, FL
Eighteen Years Experience in Brevard County

Interesting post. I wonder what it would be like to live in a structure that required no mechanical cooling - ever!

Jul 23, 2017 05:18 AM
Charles Buell

It is very possible in many areas of the country---but the houses would have to look different

Jul 23, 2017 07:39 AM
Dorie Dillard Austin TX
Coldwell Banker Realty ~ 512.750.6899 - Austin, TX
NW Austin ~ Canyon Creek and Spicewood/Balcones

Good morning Charles Buell,

I'm so glad that Kathy Streib featured your post in her "Ah-Ha" moments for the week. Indeed a very interesting and informative post. We should consider this this passive approach to improving house comfort and energy efficiency and would greatly benefit by doing so.

Jul 23, 2017 05:34 AM
Charles Buell

We spend a lot of time thinking about how we can save heating costs.  In some parts of the country thinking about reducing cooling costs is more important.  They are not too different in many ways---but they do have their differences

Jul 23, 2017 07:40 AM
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Interesting that I can drive through older areas and see awnings over windows.  They're old and rusty, but doing that passive thing they were intended.  When those were common and in vogue air conditioning wasn't a reality.

Good post on the physics of all this.  And you get grapes out of your deal!

Jul 23, 2017 05:41 AM
Charles Buell

Overhangs that shade windows from the sun are an essential part of any cooling plan for homes

Jul 23, 2017 07:41 AM
Sandy Padula and Norm Padula, JD, GRI
HomeSmart Realty West - Carlsbad, CA
Presence, Persistence & Perseverance

Charles Buell So many positive actions homeowners can take to not only save energy, but begin to enjoy their entire home, not just that portion within the four walls.

Jul 23, 2017 05:59 AM
Charles Buell

So true

Jul 23, 2017 07:41 AM
Sheila Anderson
Referral Group Incorporated - East Brunswick, NJ
The Real Estate Whisperer Who Listens 732-715-1133

Good morning Charles. This is good but house orientation is something that can't beaddressed by the time we buy.

Jul 23, 2017 06:51 AM
Charles Buell

Unfortunately yes.  The fact that we are still allowed to build homes without thinking about these simple things, flies in the face of our claims to want to see less energy used.

Jul 23, 2017 07:42 AM
Mike Cooper, Broker VA,WV, MD
Cornerstone Business Group Inc - Winchester, VA
Your Neighborhood Real Estate Sales Pro

Very interesting post, Charles. We're looking into awnings for our home right now. 

Jul 23, 2017 07:40 AM
Charles Buell

They will certainly help

Jul 23, 2017 07:43 AM
Kristin Johnston - REALTOR®
RE/MAX Platinum - Waukesha, WI
Giving Back With Each Home Sold!

I saw your post thanks to Kathys wrap up....great job!

Jul 23, 2017 07:52 AM
Sharon Lee
Sharon Lee's Virtual Assistance - Jonesborough, TN
Retired and loving life

When I was staying at Mom's and caring for her I rarely used A/C because I put window fans and box fans in the windows and at night   I would use the night time cooler air to keep it cooler and turned them around when it would warm up to draw the warmer air out. Saved a ton of money on A/C

Jul 23, 2017 08:49 AM
Susan Haughton
Long and Foster REALTORS (703) 470-4545 - Alexandria, VA
Susan & Mindy Team...Honesty. Integrity. Results.

A lot of great ideas about how to naturally cool a house;  we have a lot of big windows in our house, but we are surrounded by trees so in the winter, when the trees are bare, a lot of sun comes in and in the summer, the trees shade out most of the sun.  

Jul 23, 2017 03:06 PM
Kat Palmiotti
406-270-3667,, Broker/REALTOR® - Kalispell, MT
Helping your Montana dreams take root

Interesting ideas in both your post and some of the comments. Thanks for sharing!

Jul 24, 2017 04:28 AM
Sharon Tara
Sharon Tara Transformations - Portsmouth, NH
Retired New Hampshire Home Stager

Excellent tips!  Seems like common sense to me but I've been keeping windows closed during the hot days and open during the cooler evenings for as long as I can remember!

Jul 24, 2017 10:24 AM