Energy conservation is the main objective of green building techniques, but water management, operating costs and other concepts are considered as well. All of these ideas must be incorporated into the design of a home that will last for many years. The Environmental Protection Agency (EPA) has raised the minimum criteria for projects that can be certified as ENERGY STAR homes. Energy efficiency, a major factor in the ENERGY STAR criteria requires that a home pass a thermal bypass inspection, a good determinant of heating and cooling efficiency.
It is as important to keep the cool air in during the summer months as it is to contain the warm air in winter. Not only is more energy consumed to cool the warm air that displaces the cool air, condensation forms and causes other problems. By effectively containing the cool air, energy is conserved and the issues caused by condensation are avoided. This is accomplished by maintaining close contact between the insulation and the structure of the home.
Contrary to design ideas of the past, another green building technique used in many South Florida homes to prevent hot, moist air from entering the home is to have an unvented attic. Historically, homes have been built with a vented roof and vented soffits. Modern green building practices avoid this vented design. As air moves relatively unimpeded through fixtures into the attic, the loss is significantly decreased due to the containment of the conditioned air within the structure. In addition, rather than insulating between ceiling joists, the insulation is applied directly to the underside of the roof decking. This cools the attic, relieving a great deal of the strain from the HVAC system and allowing it to operate much more efficiently. This design is referred to as a “closed envelope”. It is also important to consider the type of spray foam used. For example at Zahn Development we chose to use Icynene LDR-50 in our recent home for sale. This product is a bio-based spray foam formulated from canola oil that contributes to a healthier indoor air quality while providing the maximum energy efficiency.
The science of green building practices improves energy efficiency and resistance to water intrusion without restricting comfortable living. To comply with more stringent environmental requirements, closer contact between the insulation and the rough structure along with a tightly sealed attic are part of the ideal design. This helps to fulfill the ENERGY STAR criteria, with the added bonus of reducing maintenance and repair of HVAC equipment.
Few builders in South Florida keep these principles in mind when it comes to residential building. However, home owners have the right and responsibility to conserve as much energy as possible. Zahn Development is an expert in using these and other green building techniques; one of the green homes in Florida we currently have for sale is a prime example of putting these methods into practice.