Seattle Home Inspector's Blog


Nature's air conditioning


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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Comment balloon 19 commentsCharles Buell • July 22 2017 02:12PM


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

Posted by Kristin Johnston - REALTOR®, Giving Back With Each Home Sold! (RE/MAX Realty Center ) 5 months ago

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. 


Posted by Eugene Kanciar, Our Experience, Your Peace-of-Mind (EKAN Home Inspection) 5 months ago


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!!


Posted by Jeff Dowler, The Southern California Relocation Dude - Carlsbad (Solutions Real Estate ) 5 months ago

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.

Posted by Joe Pryor, REALTOR® - Oklahoma Investment Properties (The Virtual Real Estate Team) 5 months ago

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.

Posted by Belinda Spillman, Colorado Living! (Aspen Lane Real Estate Colorful Colorado) 5 months ago

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. 

Posted by Kathy Streib, Home Stager - Palm Beach County,FL -561-914-6224 (Room Service Home Staging) 5 months ago

                          Thank you Charles Buell 

Posted by Kathy Streib, Home Stager - Palm Beach County,FL -561-914-6224 (Room Service Home Staging) 5 months ago

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

Posted by Anna Banana Kruchten CRS,CRB, Arizona's Top Banana of Real Estate! (Phoenix Property Shoppe) 5 months ago

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

Posted by Gary L. Waters, Broker Owner, Waters Realty of Brevard, LLC, ... a small office, delivering big service! (Waters Realty of Brevard, LLC) 5 months ago

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.

Posted by Dorie Dillard, Serving Buyers & Sellers in NW Austin Real Estate (Coldwell Banker United Realtors® ~ 512.346.1799) 5 months ago

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!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) 5 months ago

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.

Posted by Sandy Padula and Norm Padula, JD, GRI NMLS#1483386, Presence, Persistence & Perseverance (Realty One Group) 5 months ago

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

Posted by Sheila Anderson, The Real Estate Whisperer Who Listens 732-715-1133 (Referral Group Incorporated) 5 months ago

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

Posted by Mike Cooper, Your Winchester, VA Real Estate Sales Pro (Cornerstone Business Group Inc) 5 months ago

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

Posted by Kristin Johnston - REALTOR®, Giving Back With Each Home Sold! (RE/MAX Realty Center ) 5 months ago

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

Posted by Sharon Lee, Retired and loving life (Sharon Lee's Virtual Assistance) 5 months ago

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.  

Posted by Susan Haughton, Susan & Mindy Team...Honesty. Integrity. Results. (Long and Foster REALTORS (703) 470-4545) 5 months ago

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

Posted by Kat Palmiotti, The House Kat (Grand Lux Realty, 914-419-0270, 5 months ago

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!

Posted by Sharon Tara, New Hampshire Home Stager (Sharon Tara Transformations) 5 months ago