What makes a house...green, as in healthy, energy effecient?
Answers:
There is a preliminary standard for houses to get a LEED (Leadership in Energy and Environmental Design) certification. It works on a point system.
Some of the things that will make a building green are:
Low Embodied Energy- The materials used in the construction do not require a great deal of energy to produce them. As a general rule this includes using materials that are locally available (fuel to transport them is considered embodied energy). Another option is to use waste materials. Like with concrete having at least some of the cement replaced with fly ash, because fly ash is a waste material.
Environmentally Friendly Materials- The materials used are easily disposed of at the end of the lifespan of the structure. Either they are biodegradable or easily recyclable.
Spacing to other homes and infrastructure- Does the building require new roads or underground plumbing? How far is it from goods and services and places of employment? Is there undeveloped space (parks) nearby? Also the if you build homes so that they share a common wall the amount of heat lost is much lower.
Good Indoor Air Quality
Method of Construction- If your area has a great deal of temperature change or even if it doesn't you may consider using a different form of construction than standar 2x4 stick framing. You can use 2x6 studs and it would allow for more insulation. Also you can look into systems such as Insulated concrete forms because the insulation stabilizes the temperature of the concrete giving insane R-values.
Design considerations- Have the long axis of the house running from east to west. Design your overhangs such that during the summer they won't allow additional heat from the sun into the house by shading the windows but will allow heat in during the winter. Lower square footage of home. Maybe earth contact.
Low Energy Usage- The appliances use a low amount of energy (energy star compliant). You can also use alternative methods of heating and cooling such as geothermal or passive solar heating. If your area would allow it use solar to generate some electricty or to heat water. Use of natural lighting (can light up to 12' into a room if designed properly), use of energy efficient electric lighting (flourescent over incandescent).
Low water demand- Use of low-flow fixtures, Not putting in a sprinkler system for the lawn or if you do using a gray water system with a reservoir.
Landscaping- Using native species of plants and trees that don't require a lot of water to survive depending on your area.
There's a lot of considerations but the increased expense will sometimes keep people from doing it eventhough the odds are they'd recover the cost over the time they owned the house in the lower utility bills.
Other answers:
This site will help you to learn more.
This site will help you to learn more.