Today's New Homes: Engineered to Perform
Today's new homes are engineered to perform, with many highly engineered systems designed to work together. (Courtesy of Beazer Homes)
Your new home consists of a surprising number of components and systems, each designed to work in concert with each other.
New homes may look similar to their predecessors, but behind the walls is a different story. They’re engineered and optimized for a high level of performance and energy efficiency.
Regardless of architectural style, on the outside a new home doesn’t look much different than its older counterparts. But beneath the surface is a finely tuned piece of machinery — a building that offers unprecedented levels of comfort, durability, indoor air quality and energy efficiency.
There’s no question that new homes are built to last longer and operate more efficiently and less expensively than their older counterparts. To put it another way, new homes are engineered to perform. They’re consistently comfortable with no cold or hot spots; constantly circulate fresh air for a healthy indoor environment; and provide energy for heating, cooling and hot water at monthly rates that won’t bankrupt homeowners. Thanks to the use of engineered lumber, prefabricated components and advanced framing techniques, new homes are sturdier and have a longer shelf life.
As you shop for a new home, you’re going to hear a lot of terminology, including “smart,” “green,” “sustainable,” “energy efficient” and “high performance.” You might see the familiar blue Energy Star label on the circuit-breaker box or the home may be certified under another third-party, green-building program such as LEED, Built Green or EarthCraft.
Older homes tend to have problems such as air leakage, damp insulation and ineffective drainage, which results in high operating costs and an uncomfortable living environment. That’s why there’s such a keen focus on the building envelope — the roof, exterior walls and floor of the house. The building envelope determines how much energy will be needed to maintain a comfortable indoor environment relative to outdoor conditions. In new homes, it’s designed to substantially reduce heating and cooling costs.
Another term often used in conjunction with building envelope is building science: the study of the interaction between occupants, building components/systems and the surrounding environment. Building science focuses on the flow of heat, air and moisture. A home’s systems must all work together to achieve optimum energy performance and comfort.
Top builders such as Pardee Homes in Los Angeles, Calif., view a home as a collection of related systems and build it so that all the components perform well. “The time invested in analyzing building science has paid important dividends, helping us grow and strengthen our program incrementally; master the green building blocks; and incorporate them in a feasible and practical way,” says Joyce Mason, vice president of marketing for Pardee.
More bang for the buck
Thanks to changes in the U.S. Department of Energy (DOE) Model Energy Code, new homes are 30 percent more energy efficient than those built just a decade ago. The latest code revisions will go even further and call for better air-sealing techniques to reduce heating and cooling losses; improved efficiency in windows and skylights; increased insulation in ceilings, walls and foundations; less wasted energy from leaky heating and cooling ducts; improved hot-water distribution systems that reduce wasted energy and water in piping; and heightened lighting efficiency.
Three of the most critical components affecting a home’s energy efficiency and comfort are: the heating, ventilation and cooling (HVAC) equipment, ductwork and insulation. Because these components are highly engineered to work together, they must be selected and planned out well in advance of construction.
A best practice is for the builder or HVAC contractor to conduct a comprehensive analysis based on the square footage of the home; the type of insulation; the entry-door materials; the amount of glass; and the orientation of the home to select the right size heating and cooling unit. The size of HVAC equipment is usually expressed in BTUs (British thermal units) or tons. Keep in mind that larger homes may require more than one unit.
Once the house is framed and the mechanical system is roughed in, the HVAC contractor installs the furnace and runs the ductwork. When the home is almost completed, the outdoor condensing unit for the air conditioning is installed.
“The HVAC contractor visits the home at least twice — the first time to set the indoor equipment such as a furnace and lay out the ductwork and the second time to set the outdoor equipment, complete the connections and start the system,” says Steven Ross, business development manager in Dallas, Texas for Ingersoll Rand, the parent company of Trane, Schlage Locks and Nexia Home Intelligence.
The efficiency of an HVAC system is expressed in terms of its SEER (Seasonal Energy Efficiency Ratio) and AFUE (Annual Fuel Utilization Efficiency) ratings. SEER relates primarily to the air-conditioning system, whereas AFUE is more applicable to furnaces.
“An 80-percent AFUE rating means that for every dollar you spend, you get 80 cents worth of heat,” says Ross. A system with a 95-percent AFUE rating will obviously give you more bang for your buck, though it costs more upfront due to enhancements such as an extra heat exchanger to circulate the hot air longer to increase the efficiency. However, if you live in a cold climate and run the furnace frequently, it usually makes sense to pay for the added efficiency of a higher AFUE rating.
“Typically you’ll see 90 percent or 95 percent furnaces in the north and 80 percent furnaces in the south, although current Energy Star 3.0 and upcoming 4.0 guidelines both require minimums of 95 percent AFUE for North Region states and 90 percent AFUE for south region states,” Ross says. Energy Star program requirements list the states that fall into each region.
The Model Energy Code requires new homes to have HVAC equipment with a minimum 13 SEER rating. In more expensive homes, some builders now include 15 and 16 SEER equipment as a standard feature. Some builders are taking energy efficiency to the next level with net-zero energy homes, which produce as much power as they use due to a combination of technologies such as solar photovoltaic panels, solar thermal collectors and geothermal heating and cooling systems. It may sound like an expensive proposition, but in the last few years the price tag of a net-zero home has decreased considerably.
The technological revolution
Prior to the computer age, architects and designers produced plans and construction drawings by hand. Today they use computer-aided design (CAD) software. CAD programs let the designer switch between two-dimensional and three-dimensional views; zoom in and out; and manipulate, rotate and change the scale of images. CAD software speeds up the design process and results in fewer errors, which translates into a better-designed home.
Home technology has grown in leaps and bounds since the National Association of Home Builders formed the Smart House Limited Partnership in 1984. Smart House L.P., a consortium of building-product manufacturers, no longer exists. But the concept of an intelligent house where a single, unified wiring system (known as structured or integrated wiring) connects the HVAC, security, lighting and entertainment systems has become quite sophisticated. This so-called home automation technology allows homeowners to monitor all of their key systems from a centralized control panel.
Today it’s also possible to monitor a home remotely using a mobile phone or tablet computer — a great convenience for homeowners when they’re out of town or want to keep tabs on a vacation home.
Now that many people no longer have landlines, the most intelligent home is a wireless one. “We’re seeing a lot more builders use wireless systems because they have limitless capabilities," Ross says. “There’s no need to install structured wiring in advance before the drywall goes in and the builder or home buyer knows what they need and where.”
Wireless automation allows many of a home’s systems to be controlled remotely, from thermostats and window blinds to entry doors and HVAC systems. If you leave the house and forget to reset the thermostat, just pull up an app on your cell phone, tablet or computer and change it. If you’re on vacation in Florida and you get a text message reporting that the temperature in your New England home has dropped 5 degrees below the desired set point, you can have it checked out without cutting your trip short. From any location, you can unlock the front door to let in a service technician to fix the washing machine.
Not your grandfather’s windows
The products and materials that go into new homes have been upgraded and improved, with often dramatic results. Take windows, for example. Over the last 25 years, what used to be panes of glass in a hole in the wall are now crucial elements in the overall energy efficiency of a home. There are so many styles, frames and glass options available that builders can easily zero in on exactly the right window for a home’s energy-performance requirements, price point and style.
Most new homes come standard with dual-pane windows, which have space between two panes of glass that is filled either with air or a gas such as argon or krypton. This provides more insulation than a single-pane window. Energy Star-rated windows have three or more panes for greater energy savings.
To allow airflow between panes and reduce or prevent condensation, good-quality windows have warm-edge spacers made either of fiberglass, vinyl, foam or steel. They also have a low-emissivity, or low-e, coating that blocks out infrared rays from the sun, which can make a home hotter in the summer and fade flooring, carpeting and furniture over time.
Vinyl and fiberglass window frames reduce heat transfer and improve the insulation factor of the home and building envelope.
You may not recognize them as such, but it’s become common for new-home builders to use “fabulous fakes” — products and materials that look like the real thing, but in many cases are less expensive, more durable and easier to maintain. These include fiber-cement siding, polyurethane moldings and stone veneer.
Green certification programs: what they mean to you
Today many builders certify their homes under a third-party national or local green-building program. Green builders don’t always seek certification, but knowing that a new home is certified is one way for a buyer to ensure that it’s energy efficient and will last a long time.
“Buyers looking at new construction are seeking a higher-performing home,” says Pardee Homes’ Joyce Mason. “Green building is integral to that performance and quality.”
Mason points out that a decade ago, green products and practices were just getting started when it came to production homes. “Now manufacturers have stepped up the choices in green products,” she says. “They’re more tuned in to building practices, so today’s products fit more smoothly into building processes and cost less. That makes it easier for builders to offer green homes more affordably.”
In recent years, consumers have become more familiar with LEED, which stands for Leadership in Energy and Environmental Design. The National Association of Home Builders (NAHB) Research Center certifies homes to the National Green Building Standard, the only residential green-building rating system approved by the American National Standards Institute (ANSI).
Energy Star is arguably the country’s best-known green program. When the U.S Environmental Protection Agency (EPA) started it in 1992, Energy Star was a voluntary labeling program designed to identify and promote energy-efficient products in order to reduce greenhouse gas emissions. In 1996, the DOE began partnering with the EPA on such product categories as major appliances, lighting and home electronics. The EPA also extended the Energy Star label to cover new homes.
Builders who choose to partner with Energy Star must meet a rigorous set of guidelines that include:
• A high-efficiency HVAC system;
• Building practices and materials that protect the roof, wall and foundation from water damage and that reduce the risk of indoor air quality problems; and
• Comprehensive air sealing, properly installed insulation and high-performance windows.
Energy Star builders are required to work with certified Home Energy Raters, who use the Home Energy Rating System (HERS), a standardized measurement of a home’s energy efficiency. The HERS index ranges from zero to 150. The lower a home’s HERS score, the more energy efficient it is. Home Energy Raters evaluate the builder’s architectural plans to help choose the best combination of energy-efficient features for the home and perform a number of inspections and diagnostic tests during construction. Once its energy efficiency has been verified, the home receives the Energy Star label.
Remember that not every home built by an Energy Star partner is necessarily Energy Star certified – check with your builder to make sure the specific home you want is certified.
Better building practices and materials
Home builders have at their disposal an array of techniques, products and materials that reduce construction time, labor and waste and result in a better-performing house. Four of the most widely used products are:
• Structural insulated panels (SIPs) are made in the factory with an insulating foam core sandwiched between two structural facings, typically oriented strand board (OSB);
• Spray polyurethane foam is used to seal the entire building envelope and prevent air and moisture infiltration;
• Insulating concrete forms (ICFs) are interlocking modular units, similar to Lego bricks, that are dry-stacked and filled with concrete to form the foundation; and
• Engineered lumber is the generic term for a group of products that includes plywood, OSB and hardboard. The products are made by gluing strands or pieces of scrap hardwood or softwood together. Both structural and finish products are made with engineered lumber, from I-beam joists and roof trusses to flooring.
Under the DOE’s Building America program, the NAHB Research Center has done field work with builders across the country and developed recommended building practices to create a tight, efficient building envelope. For example, optimized framing (also called advanced framing or optimum value engineering) allows more space for insulation and minimizes the amount of lumber used to build a house, without compromising its structural integrity.
The Research Center also established the National Housing Quality (NHQ) Awards program in 1993 to recognize management excellence in the home-building industry. Entrants are evaluated in eight categories including leadership, customer satisfaction and construction quality. As the winners will attest, the NHQ Awards program is setting the bar very high for their peers — and that’s a good thing for new-home buyers.
Susan Bady has been writing about the housing industry for 25 years. A contributing editor to Professional Builder, Custom Builder and HousingZone.com, she has also contributed to Better Homes and Gardens’ Home Plan Ideas.