Some Green Building Design Criteria

What is commonly called “green building” today is more than just a set of practices that lead to environmentally friendly construction.  The benefits of green building design can lead to not only a reduction in consumption of resources, but also to a reduction in your monthly expenses.  Whether you wish to approach green building from the standpoint of saving the planet or saving your money, you may be pleasantly surprised to find that both can be achieved merely by considering a few basic concepts.

The selection of the building site is paramount to the green building process.  Unfortunately in the western NC region which we call home, steep grades are frequently all that are available or affordable to the prospective home owner.  When working to design a home on a steep lot, one thing must be clear:  keep the plan as shallow as possible (from front to back) in order to reduce construction cost and environmental impact.  A favorite saying among contractors in our area is “anything can be built if you throw enough money at it.”  This may be true, but the result can jut awkwardly out of the hillside instead of developing harmoniously within the landscape.  Controlling rainwater on the building site also merits close scrutiny.  Collecting and re-distributing runoff should definitely be of important concern to the green plan.

Dimensions of the building footprint play a large role in responsible home design.  Concrete blocks, sheets of plywood, dimensional lumber, all come straight from the manufacturer in pre-cut lengths or pre-cast units.  Why not create a plan that takes advantage of this modular basis?  For every written dimension that ends with a fraction of an inch, or is not divisible by a building industry standard unit, this translates in the field to increased labor and increased waste.  Labor and waste are not to be taken lightly in the pursuit of a green building design.  Aside from the obvious environmental impact of waste is the added expense of dealing with it.  Likewise, even though the cost associated with labor may come immediately to mind, a reduction in labor will save not only funds but extra trips to the job site (and therefore the associated fuel consumption).

Conditioning the home is also a principal consideration in the evolution of green construction plans.  The methods and magnitude of heating and cooling depend on your needs.  Seasonal conditions vary greatly in our mountainous climate, and also change with elevation.  There are natural options available to supplement your home’s conditioning systems, such as the compass orientation of the footprint, convection air flow throughout the interior, shading the exterior with overhangs or vegetation, and making use of the Earth’s ambient temperature below grade. 

Options for green heating and cooling are generally defined by their consumption of fuel.  The industry constantly strives to make improvements in the efficiencies of traditional devices such as furnaces, heat pumps, and water heaters.  However, for those who wish to go further with green heating and cooling, non-traditional options do exist.  Geo-thermal heat exchangers are similar to traditional air-to-air heat pumps, but instead they exchange heat with the ground, which has a more constant temperature throughout the year than the air.  Under floor radiant heating may be used in place of forced air systems, which can contribute greatly to the quality of the environment within the home.  On-demand water heaters will operate only when hot water is called for; they do not maintain a constant reservoir, and as such will not only reduce consumption but also outlive traditional tank water heaters by as much as three times the life expectancy.  

Now that you have conditioned the space to your liking, maintaining a constant temperature inside the building envelope is of the utmost importance.  Everyone who builds in the mountains wants maximum glass facing their view to incorporate a “wow” factor into their home.  But depending on the orientation of the house, openings (also called fenestrations) should be carefully considered to avoid potential undesired heat gain or loss.  A “mud room” entry is helpful as an intermittent point of entry into the house that will minimize the intrusion of unconditioned air into the building envelope.  Proper insulation is critical, as is appropriate sealing around wall penetrations such as dryer vents and electrical outlets, and weather stripping around fenestrations. 

Kitchen, plumbing, and other appliances should be carefully chosen based on their energy efficiency, which is always noted in plain view with a government mandated energy guide located on each device.  Compact fluorescent bulbs, halogen bulbs, and dimmer switches should be utilized wherever possible to reduce electrical power consumption.  “Enhanced Durability” is a concept that is considered in green building design, which includes products and methods that reduce the negative effects of solar radiation, rainwater erosion and runoff, and the probability of future service calls.  Salvaged, recycled, and renewable building materials and practices are a further consideration for the green home. 

The National Association of Home Builders and the International Code Council have created the National Green Building Standard, which outlines the above and more in specific detail.  It is the responsibility of the home owner to consult with professionals in the design and construction industry for advice and implementation of green building practices.

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