Currently, green building for residential use is likely to mean one of a dozen or so techniques.  These divide into: 1) unconventional (though in some cases ancient) building materials, 2) a broad array of techniques for decreasing energy use, 3) low impact land development, and 4) water and wastewater management.

1.  Building Materials

Salvaged or reused materials.  This means collecting, preparing for use, and building with materials, which have already been harvested or manufactured.  Examples are taking wood from old barns or other structures, usually cutting them into smaller sizes to reveal the old wood grain, and using them for furniture, cabinets, flooring, or structure.  Another example is recycling and re-using of construction waste so the smallest possible percentage goes to the landfill.

Recycled materials.  In general, green builders prefer not to use the products of industrial waste for residences. Expanding the market for these products will only prolong their use.  Off-gassing and harmful effects from chemical manufacturing have created a serious global situation and the need to go green has recently become apparent.  Biomass materials provide an eco-safe alternative to recent traditional materials   Look for synthetic or recycled material promoted as green, but be sure to do your homework as there may be a more sustainable biomass alternative.  It is important to note that green options are not always the best.  Each project and situation requires a unique solution.  MMHG building techniques rely on a cost effective decision making process to minimize environmental impacts, create a comfortable finished product and make the most of your budget.

 
Straw bale, cob, adobe, and rammed earth.  One option is straw bale construction.  Cob, adobe, and rammed earth are fascinating, but less familiar on the East Coast.  Cob and adobe are a mixture of straw and mud; rammed earth is earth (usually from the site), often mixed with cement and punched into wall shape with earth moving equipment or formed into bricks.

Green roofs.  A green roof is flat or gently sloping, covered with living plants, usually species such as sedum which require little water.  Green roofs are very popular in European cities, especially in Germany.  They reduce the heat island effect in central cities, and they reduce runoff.  Green roofs are usually planted in a thin layer (4-5”) of a porous material (an extensive green roof), although almost any arrangement of a membrane and soil or
soil substitute is possible.  One builder created a green roof from discarded carpet pad, covered with manure, and left it for nature to seed.  It is doing quite well.

2.  Energy use

Many of the above techniques have energy use benefits.  Straw bale walls, for example, have an R-40 rating and are very energy-efficient.

Passive solar energy.  Passive solar energy means designing the house to take advantage of the sun’s rays hitting the southern side of the house, with overhangs so the summer sun is blocked but the winter sun, which is lower, shines in below the overhang.  Even in a house which does not have a southern orientation or overhangs, a great deal can be done by moderating the flow of air and sunlight through shades, curtains, fans, opening the
windows, closing off cool or warm rooms, and choosing where one will sit and what to wear.

Active solar energy.  This has at least two types, hot water and photovoltaic.  Of these, PV is much more expensive and usually never quite pays for itself with current technology and pricing.  This is changing.  A PV system generates DC electricity, requiring an inverter to convert to AC, and batteries to store the power generated.  PV systems can be used for net metering, in which the electric meter runs backwards and the utility company effectively pays the consumer during that time.  Many people are trying to move “off the grid” meaning
no utility service.  This is attractive as a goal, but difficult to achieve.  

Solar hot water.  Especially for those clients with swimming pools, a solar hot water system has a short payback period and is a very good alternative.  A hot water system preheats the water and then it is moved to a conventional tank to be heated more, for a net cost saving.  

Wind and water.  Wind towers and water power function well in some parts of the country.  Water power tends to interfere with the natural flowing of the stream, a major disadvantage.

Geothermal.  In use in around the country and often cost-effective, geothermal means drilling a hole into the ground as one would for a well and creating a closed loop system to cool or heat a liquid to the temperature of the earth, which stays at 55 degrees year round: warmer than the air in winter and cooler in summer.  Then the liquid is used by a heat pump system to generate heating or cooling in the house.

Smart houses.  Smart houses do many things, including monitoring and reducing energy use.  Houses can also be designed to report to a caregiver the movements and usage patterns (the stove was just turned on) for an elderly or infirm person.

3.  Low impact land development

Land development means the process of subdividing land and putting in roads and utilities, including water and sewer or well and septic in rural areas.  The land is then ready for building.  Low impact land development usually means developing less density than would be permitted by law, locating the roads and buildings to avoid steep slopes, woods or agriculture, and doing a minimum of grading.  Examples of low impact land development techniques are creating a small construction envelope around the building site, the use of permeable pavements, and road building without soil compaction (which damages tree
root systems).  In wooded areas, low impact development includes minimizing the creation of forest edges (clearings) which reduce habitat for Forest Interior Dwelling Species of birds.

4.  Water and wastewater management

Storm water management is usually a part of the development process for new construction, but existing buildings can be analyzed and improved.  Techniques such as green roofs, reducing impervious surfaces, and sheet feeding of rainwater into vegetative swales, instead of concrete, help to reduce or eliminate storm water runoff from the
site.  

Wastewater within the home can be disposed of by using alternatives to conventional sewer or septic systems, such as composting toilets and grey water gardens.