The next option is to strategically plant shade trees on the south east to south west sides of our homes.  Recently, we have lost dozens of mature trees throughout our neighborhood leaving homes exposed to the sun where they previously were shaded. In other cases good shade trees are past their prime and new trees should be planted now to replace the old trees.

The fall and early spring are the best times to plant trees because their roots are dormant and they have the best chance of survival.  Landscape architect Li Qi suggests the following tree species and notes the advantages of each.

Oak Tree

Willow, Oak, Elm, Maple, and Black Gum, are good large trees if there is enough room in the yard.  River Birch is a popular large tree that is fast growing but will kill the grass around its base because of its shallow root system.

Japanese Maple

Smaller trees include Japanese Maple, Crape Myrtle (don’t cut it back), Crab Apple, America Hornbeam, Cherry Tree (a lawn tree), and Dog Wood (likes shade) all of which are available and popular.

Magnolia Tree

For evergreen shade trees Li suggests Savannah Holly and Magnolia trees.

Cox discusses the obvious and not-so-obvious consequences of our love of cool, comfortable rooms.  In the U.S., home air conditioning accounts for almost 20% of residential energy costs.  That doesn’t sound so bad until you realize that’s as much electricity as is used in the whole of Africa.  Air conditioning has allowed us to build large and expanding cities in locations with fragile ecosystems (think southern Florida, or Arizona).  It encourages us to remain indoors rather than moving around outside — isolating us from other people and reducing our physical activity.  It’s changed the way we sleep, travel, work, and play.  Neighborhoods that once rang with the sounds of kids playing outside during the summer months are now silent apart from the ceaseless whir of AC units.

Our dependence on air conditioning has also made us less resilient and less tolerant of heat, physically but especially mentally and emotionally.  We feel more miserable in the summer because we never fully adapt.  When we do go outside, the exposure to heat actually stresses our bodies more.  And air conditioning creates closed environments that trap and amplify the effects of many allergies and illnesses — to say nothing of the mold and bacteria that may be growing in the cooling unit.

Cox is not all doom and gloom, thankfully.  He also discusses ways you can reduce your dependence on air conditioning by using fans, creating cooler roofs, and using vegetation to shield your house from the sun.  His suggestions are all the more welcome because Cox believes there will almost certainly be restrictions placed on our electrical use in the future by limits to our generating capacity.

It’s just more evidence that we should be looking for ways to get out from under our AC units before we really lose our cool.

Links To Check Out

• Losing Our Cool web site: http://www.losingourcool.com/
• Stan Cox Losing Our Cool blog: http://losingourcool.wordpress.com/
• Read the first chapter of Losing Our Cool on ColdType (PDF)
• Listen to a one-hour interview with Stan Cox from the NPR program On Point from WBUR, Boston
• Listen to Stan Cox talk with Kai Ryssdal on Marketplace from American Public Media — along with some tips for living without AC

We presume the designers included a way to harvest the upper stories.

You can hardly get more sustainable than a vertical garden.  For more on the whole subject:

• Pictures and discussions of 15 living walls
• NY Times article about gardens that grow on walls
• Videos on how to create a vertical garden
• Lifehacker’s take on vertical gardening
• Vertical gardens for small spaces

5-26-09

When it’s time to re-shingle your home you have the opportunity to reduce cooling bills by choosing shingles that reflect solar radiation.  One of the ways shingle manufacturers rate their shingles is by their solar reflectance index.  By choosing a shingle with a solar reflectance index of 29 or greater you will guarantee yourself a number of cost saving benefits:

1) Reduced energy costs by reducing the air conditioning load

2) Longer air conditioner equipment life by reduced loads

3) Increased roofing life due to reduced differentials in heat-cool cycles

In conjunction with new shingles, it is a good opportunity to add insulation in you attic.  If insulation is added between your roof rafters you must allow heat that forms between the insulation and the wood roof sheathing to escape at the roof ridge.  Your roofing contractor can install ridge vents during re-shingling.

If you want a good estimate of the money you will save, there are a couple of on-line calculators that you can use to estimate your energy savings.  The calculators will prompt you to fill in the cost of gas and electricity by $ per therm and $ per kilo watt hour.  This information is on your gas and electric bills.  They will also prompt you to fill in the solar reflectance value and the thermal emittance value of the shingle you choose.  To find these values you will have to go on-line or call the manufacturer’s rep. because this data is not usually published by the shingle manufacturer or supplier.  All other required data is pretty straight forward.

The DOE Cool Roof Calculator was developed by the U.S. Department of Energy’s Oak Ridge Laboratory. This calculator provides an estimate of cooling and heating savings for small to medium size facilities. http://www.ornl.gov/sci/roofs%2Bwalls/facts/CoolCalcEnergy.htm

The EPA Cool Roof Calculator is provided by ENERGY STAR. This calculator allows the designer to input specific details about a building, including heating and cooling systems as well as location and the cost of energy.  It calculates costs per 1,000 square feet of building foot print, so you will need to modify the savings by the actual foot print of your roof. http://www.roofcalc.com/RoofCalcBuildingInput.aspx