Three Basics of Energy Efficiency
But in the end I decided to focus on three basic principles of high-performance, sustainable building design that are guaranteed to steer you in the right direction when designing and building an energy-efficient structure. The three tried-and-true basic principles are:
1. Harvest as much free energy as possible
2. Conserve energy
3. Utilize efficient energy systems.
Like a three-legged stool, all of these principles are dependent on one another in order to make a home function properly and at optimal levels. When combined with logical energy efficiency strategies and products (including an integrated design and construction process), these principles will make it easier and more cost-effective to create a high-performance building of any type.
1. Harvest as much free energy as possible
The basic premise here is to use the home's orientation on the site to take full advantage of the free energy the sun provides daily. Indian tribes in the southwestern United States knew it made sense to orient a dwelling on an east-west axis to harvest the benefits of sunlight. By locating most openings (windows, doors, etc.) on the north and south sides on a building, homeowners and building designers can maximize the benefits of daylighting and keep solar heat gain to a minimum.
This basic principle should be used whenever possible for the buildings we create today, as it is the most significant factor contributing to efficient energy performance. Basic building orientation strategies can be utilized in conjunction with high quality windows, doors, shading devices and other strategies to improve the performance of a building in both a passive and active manner. Another excellent product strategy is to use skylights to bring free sunlight to interior areas of the home.
Of course, if your home already exists, its orientation will be fixed. So from a renovation perspective, you can still consider eliminating poorly located windows or replacing them with new higher-quality window systems.
Additionally, landscape elements, such as deciduous trees, can be strategically located to keep the hot sun from directly contacting your windows in the summer. In the winter, when the trees lose their leaves, they will permit more light and heat to enter your home.
2. Conserve energy
Conserving energy by maximizing the design and performance of the building envelope (which consists of the floors, walls and roof) is one of the most important (and my favorite) areas of building science. After determining the most effective orientation for the building on a particular site, my attention always goes immediately to exploring what wall, roof and window systems I can use to create the highest-performing building at the lowest possible first cost.
This is a very interesting and constantly changing part of the building science industry because of the multitude of new products that are continually being introduced into the marketplace. There are so many new technologies available that at times it seems impossible to keep up with them all, so I'll stay on track by concentrating on the basics of foundation and wall systems, structural systems, roofing materials and fenestration (i.e. window design) strategies.
Of course, homeowners can use many other products to enhance the performance of the building envelope, but it's beyond the scope of this article to discuss more than a few. Just remember that an integrated design is what we're after. For example, the windows and skylights I discussed in the first section of this article are also part of the building envelope, but that's what integrated design and construction is all about: using products and strategies that deliver benefits in different ways.
3. Utilize efficient energy systems
Now that we've provided an airtight, efficient building envelope that takes advantage of the sun, the next step involves careful consideration of the mechanical systems. This is the one area where a homeowner can make the most impact on comfort and utility savings. By rightsizing all mechanical systems used in the building, comfort will be maximized and the use of gas, water and electricity minimized.
Over-designed systems are more expensive initially and require more energy to operate, costing the owner much more through the life of the building. An under-sized system will never be able to keep up with the demands of the building, negatively affecting the comfort level of the building's occupants, and it will contribute to inflated utility bills as well. In addition to being efficient, a properly sized HVAC system can also result in the reduction of ancillary materials like ductwork and piping, which can further reduce initial costs.
Energy-efficient lighting should also be a critical part of your selection process, as it has become an increasingly important component of a high-performance home. Good lighting design starts at - you guessed it - the building orientation stage of design. Proper orientation can drastically reduce the need for artificial lighting by using as much sunlight as possible to light the home's interior.
After a good daylighting strategy is employed, homeowners should focus their attention on what types of artificial lighting to choose. Because light fixtures not only generate light but also heat, fixtures should be carefully analyzed for the amount of heat produced, which can negatively affect the sizing of mechanical equipment needed to cool the space. Factors to consider include the amount of energy consumed by each fixture, the type of bulbs used and, of course, the style of the fixture to ensure they fit with the overall design criteria.
I was once told that if you spend your life climbing a ladder that's placed on the wrong wall, you're sure to be disappointed when you reach the top. So if energy efficiency is your goal, use the three basic rungs of harvesting free energy, energy conservation and utilizing efficient energy systems to make sure you're satisfied with the energy performance of your building when it's completed.
Charlie Popeck is the president of Green Ideas Environmental Building Consultants and a contributing editor to Smart HomeOwner. Green Ideas specializes in helping design, construction and facility management teams understand and implement building science and sustainability into their projects. He can be reached at 602-512-0557 or Charlie@Egreenideas.com.