Energy Efficiency In Building Design
Understanding The Characteristics Of Energy Efficient Buildings
With so much focus on the environment these days, more and more architects and contractors are turning their attention to designing and building structures that minimize energy loss. These designs reduce the energy needed for cooling and heating regardless of the equipment or energy source used for climate control. Architects build in features that reduce the energy demand by avoiding waste. The three main characteristics of energy efficiency buildings are bioclimatic architecture, a building envelope, and controlled ventilation.
Bioclimatic architectural designs make the best use of environmental resources, including solar energy, based on the local climate. The compact shape of such a building has fewer surfaces in contact with the exterior. The main doors and windows face south whenever possible. The indoor floor plan takes into account heating requirements of the various interior spaces.
The orientation of the building ensures openings have protection from solar heat during the summer and winter. Protection from the sun during the summer may come from shade trees or exterior treatment with reflective surfaces and colors. The installation of passive solar radiation collection systems reduces energy needs for household maintenance.
The building envelope physically separates the exterior and interior environments. This outer shell dictates how effectively the structure can utilize natural resources for heating, cooling, ventilation, and lighting. With a tight envelope, building occupants enjoy improved indoor air quality and better moisture management for a more comfortable interior environment. Uncontrolled air leaks can increase a home’s power usage by as much as 50%.
Advancements in modern ventilation technology make it possible to control incoming airflow mechanically. This is more efficient than allowing outside air to leak through any available gap or crack. The air travels through a filter, is heated or cooled to the thermostat setting, and dispersed throughout the building.
The tight envelope is responsible for maintaining indoor air quality. It prevents pollen from coming indoors where it can trigger allergies and aggravate other more serious upper respiratory problems. Efficient designs seal off the garage from living spaces to eliminate exposure to paint, vehicle, and household cleaner fumes.
Moisture is always a concern because it creates the ideal environment for mold growth. Hot, humid air entering from outside on a summer day can cause condensation on interior surfaces. At the same time, warmed air flowing to the exterior on a cold winter day can cause water to condense on exterior surfaces. Air barrier materials manage moisture to prevent condensation. The areas of a building most prone to air leaks are attics, cantilevered floors, ceilings, crawl spaces, parapet wall transitions, doors, and windows. The connections and transitions between these areas and the living space are just as important for maintaining a tight envelope as using air barrier materials.
Spray polyurethane foam, or SPF, applied to exteriors and used to fill inside wall cavities, helps achieve a tight envelope. The foam acts as a weather resistant barrier, prevents air leakage, eliminates vapor penetration, and provides continuous insulation to maintain a comfortable interior. Fluid-applied barriers are also useful for resisting weather. Commercial building wraps and other self-adhered products are effective but more complicated to install properly.
Thermal insulation increases the efficiency of every component of the building envelope. This includes walls, facades, lofts, and roofs. It also reduces energy loss through pipes and water heaters. Insulation works year round to save on power usage. During the summer, it prevents hot air from getting in allowing the air conditioner to work more efficiently. During the winter, it traps warm air inside, reducing the need for heating.
Building designs should utilize natural light to reduce the need for artificial illumination significantly whenever possible. This requires precise planning to adjust for daylight variations throughout the day and year while controlling glare and balancing heat loss and gain. A good lighting design is functional but also enhances the surrounding architecture for a visually pleasing result.
Proper ventilation exhausts stale air to the outside while distributing fresh air inside. Without enough airflow through the structure, humid air condenses on any cold surfaces with poor or no insulation. This excess moisture allows fungi, molds, and mildew to flourish. Mechanical ventilators, temperature control systems capable of removing moisture, and the materials used in construction of the building must work together to properly ventilate the interior.
Energy efficient designs represent a growing trend in the construction industry. Consumer demands on the industry dictate that architects and builders respond with buildings designed to perform without wasting energy. These designs offer widespread benefits from preserving natural resources to saving on household operating costs.