Lime the Cliffs Cottage at Furman University in the US, in times of global warming, getting your hands on a "green home" might be a good investment.
The cottage was built on campus in 2008 to serve as a model of environmentally responsible design, sustainable building techniques and materials, and energy-saving systems.
The home has 3,400 square feet, but is so energy efficient that it can be heated and cooled for less than 75 dollars a month.
It features a passive solar design, which integrates an assortment of building features to reduce the need for cooling and heating and daytime artificial lighting.
The home is situated along an east/west axis to maximize solar heat gain in the winter and minimize it in the summer.
On the south side of the cottage, a long roof overhang shades the house in summer and allows the sun to heat the home in the winter months.
The home uses an energy-efficient, precast foundation, natural stone and two types of insulation to seal the home and preserve its thermal mass. The exterior stone absorbs heat that is slowly released after the sun goes down.
The spray foam insulation, free of formaldehyde, seals off air leakage, moisture, airborne allergens and noise pollutants.
The fiberglass insulation is environmentally sound, with a minimum certified recycled glass content of 25 percent.
The pervious concrete, permeable brick and gravel pave used across the site in parking areas and main walkways allow stormwater to filter back into the soil instead of draining into streams and rivers.
The Cliffs Cottage has a geothermal heating and cooling system, which is the most environmentally responsible and energy efficient system available.
The direct exchange ground source heat pump uses the earth's constant underground temperatures to heat the home in the winter and cool it in the summer.
Ground source heat pumps can reduce heating and cooling costs by as much as 50 percent, and they usually last three times longer than air source systems.
Also, the house is furnished with products that are environmentally sustainable and locally sourced, from the bamboo floors to the kitchen cabinets to tile made from recycled glass.
Much of the furniture is constructed from reclaimed or sustainable harvested wood or trees removed for real estate development, and fabrics are made without toxic dyes.