Be an Energy Star: Homes that save energy like never before

This is the fourth article in an 8 part series intended to educate home buyers and builders on the different aspects of building “green”. Be sure to pick up the next issue to read all about stratetegies for slashing your energy consumption!

Part I: Overview — Introduction to Green Building

Part II: Land Use Planning — Creating Value, Protecting the Environment

Part III: Material Science — New Options in Eco-friendly (and Healthier!) Building Materials

Part IV: Be a Miser — Strategies for Slashing Your Energy Consumption

Part V: A Drop in the Bucket — Painless Ways to Reduce Your Water Use

Part VI: Breathe Easy — Controlling Pollution Inside Your Home

Part VII: Xeriscaping — Drought-resistant, Low-maintenance Landscaping

Part VIII: Greening America — Green Certification and a Look at the Costs

ConsumptionEnergy efficiency has moved to the forefront of homeowners' consciousness about what makes a dream home  — in both existing and new construction. The manufacturing, construction and operation of residential buildings consume approximately 20% of America’s energy every year. But with advances in construction techniques, building materials and awareness, a reduction of home energy usage of 10, 20 even 30% is now a very real possibility for any homeowner.

Skylights can provide as much light as dozens of
light bulbs during the day.

Efficient By Design

Building a truly energy conscious home begins before the foundation is even laid. In the design process, energy saving features should be considered alongside all of the myriad factors that determine the final plan. Explore such elements as daylighting to reduce electrical lighting requirements. A single skylight or properly positioned window can provide as much light as dozens of light bulbs during the day. Using extended overhangs can selectively admit sunlight during the low sun-angle winter months while blocking it during the high-angle summer months.

Careful analysis of the site and the local climate to determine building orientation that enhances the home's energy performance is another pre-construction must. The winter sun rises south of east and sets south of west. Placing more glass on the south wall will ensure that your home receives free solar energy. This same
orientation helps to prevent the high summer sun from entering the home. Locating spaces such as garages, storage rooms, or screened porches on the east or west side of a building provides valuable shading during the summer, as does preserving trees in these areas. Planning for operable windows that take advantage of prevailing wind patterns, enabling cross-ventilation, can reduce cooling loads.

A comprehensive plan for efficiently heating, cooling, regulating moisture and ensuring adequate ventilation is another vital step in the energy efficient design process. Fortunately, there are energy minded architects, designers and builders who can help the average homeowner navigate this complex design path. Software packages are also available to assist in these processes, and companies like Southern Energy Management offer detailed plan analysis and coordination with both manufacturers and contractors.

Even if you're not building a new home, but just want to maximize the energy efficiency of an existing home, a good plan of attack is your first step. Both Duke Power and Progress Energy offer online energy audits to analyze your power usage and suggest specific efficiency measures, along with estimated cost savings. Or you can hire a professional — a certified home energy rater — to perform a comprehensive energy audit of your home, which should include actual testing of your building envelope to identify problem leaks.

The ENERGY STAR program, a joint venture of the U.S. Environmental Protection Agency and the U.S. Department of Energy, offers an abundance of
assistance to homeowners seeking to make their homes more energy efficient. Most people are familiar with the ENERGY STAR designation for efficient appliances, but your home can also be certified as an ENERGY STAR home.

To earn the ENERGY STAR, a home must meet guidelines for energy efficiency set by the U.S. Environmental Protection Agency. These homes are at least 15% more energy efficient than homes built to the 2004 International Residential Code (IRC), and include additional energy-saving features that typically make them 20–30% more efficient than standard homes. In addition, many power companies offer discounted rates to ENERGY STAR homes.

The Department of Energy estimates that, with the help of ENERGY STAR, Americans saved enough energy in 2006 alone to avoid greenhouse gas emissions
equivalent to those from 25 million cars — along with saving $14 billion on utility bills.

“With environmental issues being a key topic in the news today, more and more consumers are looking for ways to reduce their impact on the environment and live in homes that deliver healthier indoor air quality,” says Chip Guyon, president of Anderson Homes and Vanguard Homes. “Purchasing an ENERGY STAR qualified home is a major step in the right direction.” Indeed, Anderson and Vanguard have built more than 350 ENERGY STAR homes in the Triangle.

Beginning this year, Biltmore Homes is constructing all of its new homes to ENERGY STAR standards. Heritage Knoll, Biltmore's newest Wake Forest community is its first all-ENERGY STAR community. “It's just a win-win proposition,” says Biltmore Homes vice president of operations, Scott Good. “It's good for the environment, good for the homeowner financially and good for resale values.”

Homescape Building Company's production manager, Dallas Berry concurs. “The ENERGY STAR sticker gives the homeowner the assurance that the home's energy efficiency has been verified — through every step of construction —  and by an independent party to exceed local building codes.”

The R Factor

Heating and cooling units (space conditioning) account for 50 to 70% of the energy used in the average American home, so preserving conditioned air is a vital component of reducing energy usage. Insulating attics (as much as half of a home's heat energy loss can come from inadequately insulated attics), walls, floors and crawl spaces creates an energy conserving blanket around your home.Insulation performance is measured by R-value — its ability to resist heat flow. Higher R-values mean more insulating power. Different R-values are recommended for walls, attics, basements and crawlspaces, depending on your area. Whereas typical walls in the Triangle might carry an R-value of 11, an energy efficient home would achieve wall R-values of 18 or even higher.

In addition to traditional fiberglass batt and blown cellulose insulation, there are numerous new options for upping the R-value of your home's insulation. Icynene is a water-blown foam insulation that expands to 100 times its initial size and hardens to form a complete barrier. Reflective insulation, also called a radiant barrier, is a metallic foil material (usually aluminum) designed to block radiant heat transfer across open spaces. Radiant barriers are typically used to insulate attics and floors.

Structural insulated panels (SIPs) are constructed of oriented strand board (OSB) sandwiched around an insulating core of expanded polystyrene foam (EPS). “These panels can be as large as eight feet by 24 feet and are available in a variety of thicknesses,” says Alternative Building System's Michael Dilettoso. “And the creation of a more continuous insulating envelope — without stud penetrations — results in a more constant R-value throughout the entire shell of the structure.”

Another wall panel system, AAC (autoclaved aerated concrete) consists of pre-cast panels of lightweight concrete. This building material, widely used across Europe and Asia for more than 75 years, is manufactured through a process combining sand, cement, lime, water and aluminum powder. Millions of embedded tiny bubbles make these concrete panels lightweight and also act as highly effective insulation pockets.

“With AAC, you can create a monolothic thermal mass,” says Alternative Building System's Don Yonavjak. “And with the type adhesive used, the joints — usually the weakest point in a masonry wall — create a seamless barrier with constant R-values.”

Sealing this building envelope is key to maximizing a home's energy efficiency. Air leakage accounts for between 25 and 40% of the energy used for heating and cooling in a typical residence. Leakage paths include joints between building materials, gaps around doors and windows, and penetrations for piping, wiring and ducts. There are many products available for air sealing including caulks, foams, weather stripping, gaskets, and door sweeps.

In a typical house, about 20% of the air that moves through the duct system is lost due to leaks and poorly sealed connections. Exposed ducts in attics, basements, crawlspaces, and garages should be tightly sealed. In addition, insulating ducts that run through spaces that get hot in summer or cold in winter (like attics, garages, or crawlspaces) can save a significant amount of energy.

“As part of the Energy Star certification process,” says Homescape Building Company's Dallas Berry, “we have Southern Energy Management perform a blower door test to independently verify that the house is tightly sealed.”

Windows and Doors

Low-E coatings on window glass reflect infrared
light, keeping heat inside in the winter and outside
in the summer.

Windows and doors can be the weak link in your building envelope. Fortunately, advances in materials and construction of both make it possible to enjoy walls of glass and elegant entries without sacrificing energy efficiency.

When it comes to windows, U-value is the measure of thermal performance. It describes a window's ability to conduct heat. The lower the U-factor the better the window. The U.S. Department of Energy recommends a -value of 0.4 or less. Double glazing creates an insulating air pocket of 1/4 to 1 inch. Better still, some high-efficiency windows fill this space with non-conducting gases such as argon or krypton. Low-E coatings on window glass reflect infrared light, keeping heat inside in winter and outside in summer.

For existing windows, consider the latest generation of sun-protecting coatings. These micro-thin protective sheathings bond to the inside of windows, allowing glare-controlled visible sunlight to pass through but screening out heat and ultraviolet rays. Good window film can block as much as 99.9% of UVA and UVB radiation, and up to 46% of heat is also deflected, helping to regulate the temperature throughout your home, especially in summer months. “The payback realized in reduced cooling loads can be as little as three years,” says Chris Aycock, co-owner of Sun Protection, a longtime Triangle installer of window film.

When it comes to doors, Install steel or fiberglass insulated exterior doors that have an insulation value of R-5.9 or greater. (Lower R-value doors can be used in conjunction with a storm door.) Sidelights and glass panels should be of the same high-efficiency construction and materials as all of your windows. Garage doors can represent a significant energy loss, especially if the garage is attached to the home or there is conditioned living space above the garage. “Clopay Building Products three-layer ‘sandwich’ doors, feature a layer of expanded polystyrene insulation bonded between two layers of 24-gauge steel,” says Custom Overhead Doors’ Harold Hoffmeier. “With insulated glass and a vinyl weather seal, these doors are so energy efficient that they qualify for a Federal tax credit.”

Right Side It

Always consider HVAC units that have earned the ENERGY STAR. Installed correctly, these high-efficiency heating and cooling systems can save up to 20 percent on heating and cooling costs. If your HVAC equipment is more than 10 years old or not keeping your house comfortable, you should have it looked at by a professional HVAC contractor. If it is not performing efficiently or needs upgrading, consider replacing it with a new ENERGY STAR unit.

Remember that getting the proper size and a quality installation is essential to getting the most from your new equipment. When replacing HVAC equipment, bigger doesn't always mean better. If the unit is too large for your home, you will be less comfortable and might actually have higher utility bills. Oversized equipment will operate in short run cycles, not allowing the unit to reach efficient operation and remove humidity from the air — resulting in an uncomfortable home. Your contractor should determine the right size for your HVAC equipment by using ACCA/ANSI Manual J or an equivalent sizing calculation tool that takes into account specific information about your home.

A programmable thermostat is ideal for people who are away from home during set periods of time throughout the week. Through proper use of
pre-programmed settings, a programmable thermostat can save you about $150 every year in energy costs.

The Finishing Touches

When buying an appliance, remember that it has two price tags — what you pay to take it home and what you pay for the energy and water it uses.

ENERGY STAR qualified appliances incorporate advanced technologies that use 10 to 50% less energy and water than standard models. The money you save on your utility bills can more than make up for the cost of a more expensive but more efficient ENERGY STAR model.

“It’s so important that people do their homework when it comes to purchasing energy efficient appliances,” says Bob Van Sant of Wilkinson Supply. “It’s great to have a washing machine that uses less electricity and water, but it's not so great if it doesn't get your clothes clean.” Wilkinson Supply carries European appliance lines, such as Liebherr and Míele. “Europeans have been ahead of us in energy consciousness,” adds Van Sant, "and these appliances have been engineered from the ground up for efficiency and performance.”

On the Horizon

While, the ENERGY STAR program is making great strides in increasing the energy efficiency of millions of  homes in this country, even greater advances are becoming more and more available to the average homeowner. New technologies in alternative, renewable energy sources — solar, wind and geothermal — are emerging. Sophisticated energy management systems are being installed in an increasing number of homes. And cutting-edge building materials, offering  even greater efficiencies, are being developed worldwide.

Homeowners today are reaping the benefits of energy efficiency with reduced energy costs and more comfortable, healthier living environments, as well as helping the environment. And as momentum builds, the sky truly is the limit, when it comes to energy efficiency.

For more information about increasing your home’s energy efficiency, visit www.energystar.gov.

Kelly McCall branson is a Freelance Writer