Friday, July 27, 2012

Adding Energy Benefits to Your Site!

I live and work in a house that I designed to be passive solar.  It was built 16 years ago and has been saving me energy costs ever since I moved in.  For example, I am currently sitting in my office on the south side of the house with its bank of windows and it is 99 degrees outside, but my air conditioning is not running and I am quite comfortable.

Some of what went into this house to make it passive solar can obviously not be translated into use for existing structures - which comprise the majority of residential property on the market.  Obviously, once a home is built, you cannot change it's orientation, the direction that it is facing, nor can you easily add heat sinks and trombe walls. 

You can, however, change the planting of your site.  In fact, a good portion of what makes my home passive solar is actually green and growing out of the ground outside my window.  Start with trees!  The bulk of the sun beating down on your house in the summer comes from the southwest and can be blocked or modified by trees.  Who hasn't noticed the difference in temperature on a blistering day when they step out of the searing sun and into the shade.  Remember though that you are more than likely going to have to consider two major power demanding seasons.  Winter eventually comes and that shade can become a problem.  Thankfully Mother Nature has an answer for that.  Deciduous trees planted on the south to southwestern side of your house will go a long way toward comfort control.  Chose trees that are not too fast growing as they will tend to be weaker and to break in those violent summer storms.  Also choose trees that have a nice rounded mature crown without becoming too tall as lightening is drawn to the tallest thing around and you do not want to bring it close to your house.   Trees that reach a mature height of 60 - 75' will work great for your shade factor.  They should be planted such that their projected crown width is taken into consideration.  You will want to plant them at a distance of about half the projected crown width plus 15 - 20'.  This will allow them to grow and still allow you to have adequate ventilation around your home thus preventing issues with moss and mold.

For example, a willow oak will get to 60 - 70' tall and 50' in crown spread.  It makes a beautiful shade tree with a lovely rounded crown and withstands urban pollution well due to its small leaves.  I would plant a willow oak 40' - 50' away from a building and on the southwest side if I wanted to use it for summer shading.  The easiest way to determine which direction that might be is to watch for where the late afternoon sun hits the house in the summer.

As hot as it can get in the summer, winter can also be a brutal season that chews up fuel.  By planting deciduous on your southwest building face, you are ensuring that it will also get winter sun.  This is important for winter heating.  In many places, winter winds can also be a problem.  Depending on your location, you might also need to consider planting a winter wind break.  For this you will need to plant evergreens on the north and northwest side of your home.  Remember to maintain enough distance from your home to allow for ventilation and crown development.  For a windbreak, plant evergreens such that their projected mature crowns will join to form a solid green wall.

Finally, shrubs planted along the foundation of your home are not only aesthetically pleasing, they are great for added climate control.  They act to aid in crawl space or foundation slab cooling in the summer through shading and as added insulation in the winter.

Nothing living is ever permanent in nature so plan for that.  Plant several trees instead of just one.  I prefer to see several kinds of plants - whether trees or shrubs - go into each grouping.  After all, if your prized oak planted on the southwest side of your house is hit with oak wilt and you have three of them eventually all three will die.  It is not as serious a problem if you happen to have an oak, a maple and a hickory.  One might go but you still have two others to take over.  Just make sure that you replant when one is struck.

With a little thought and some planting, you too can have a passive solar site and be a part of the 'green' movement.  It may be a new label, but it is a tactic that people have been using for ages to control their personal home environments.

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