Your home’s energy-efficiency is a bit of a complex topic what with talk of building envelopes, advanced framing techniques, R-values, the HERS Index and more. Yet understanding all of this can save you plenty of money.
Many homes today are built to the specifications of the Environmental Protection Agency’s (EPA’s) ENERGY STAR® program, including homes built by Robson Communities. Others, like Maracay Homes, build LEED-certified homes. LEED®, Leadership in Energy and Environmental Design, was developed by the U.S. Green Building Council (USGBC) in the mid-1990s.
At a Robson Resort community, each new home is ENERGY STAR-certified and built to what’s known as the Environments for Living Program Platinum Level, said Matt Guelich, senior vice president of construction for Robson Communities. “This is important to our prospective buyers because it guarantees their monthly heating and cooling usage for two years.”
Maracay Homes has opened two communities — one in Chandler and one in Gilbert — where all the homes are being built to achieve LEED certification through the USGBC, said Andy Warren, president of Maracay Homes. “Our commitment to building green homes began more than a decade ago and since then we’ve increased our efforts, refined our building practices and expanded our use of green technology each year,” he said.
What energy-efficiency entails
“LEED-certified homes are designed to use 30 to 50 percent less energy than typical homes and will meet the EPA’s Indoor airPLUS specifications,” Warren said. “These homes also will feature water-efficient fixtures, LED lighting, energy-efficient heating and cooling systems, ENERGY STAR appliances (and) Wi-Fi-enabled programmable thermostats.”
There are two categories of energy-efficiency, said LGI Homes’ west division president, Chris Kelly — the building envelope and the systems within the home. The building envelope is made up of the physical separators between the interior and exterior of a building. These include the roof, walls, floors, insulation, windows and doors. How well these form an air barrier to the outside ultimately can affect your energy bills — perhaps as much as the efficiency of the systems within the home such as the air conditioner, water heater and other appliances.
“Most consumers are not aware of the importance of the building envelope,” Kelly said. “Builders can easily market and explain the benefits of the systems within the home but struggle at times to effectively communicate the importance of the proper installation of insulation along with the air barriers that play a critical role in reducing operating costs.”
The nitty-gritty
Energy-efficiency translates into “a higher level of comfort, security and durability with less maintenance,” said Geoff Ferrell, chief technology officer for Prescott-based Mandalay Homes.
One factor that does not improve energy-efficiency is the use of more lumber in the construction of a home. Rather, Ferrell said, the less lumber you use (sometimes by relying on 2X6 studs instead of 2X4s), the more room remains for insulating material.
Increasingly, homebuilders are using what are known as advanced framing techniques.
According to GreenBuildingAdvisor.com, an organization focused on providing information related to designing and building energy-efficient homes, advanced framing aims to reduce the amount of lumber used to frame buildings to the bare minimum.
The amount and type of insulation added (fiberglass, cellulose or the more expensive spray foam) determines a home’s “R-value” — a measure of the insulation’s ability to resist heat traveling through it, according to the website for the EPA’s ENERGY STAR program. The higher the R-value, the better the thermal performance of the insulation.
Every home can be assigned a number along the HERS (Home Energy Ratings System) Index, a measure introduced in 2006 by the nonprofit Residential Energy Services Network (RESNET) to indicate overall energy-efficiency. A score of 100 equates to the energy usage of a standard American code-built structure constructed in 2006. A score of zero means that a home produces as much energy through renewable resources — such as solar panels — as it consumes.
“A typical new home today has a score of between 75 and 90,” Ferrell said. That means it’s between 10 and 25 percent more energy-efficient than a 2006-code-built home. Mandalay’s goal is to build every home with a HERS Index of no higher than 50, meaning it is 50 percent more energy-efficient than a 2006-code-built home. By comparison, a 20-year-old home likely has a score of about 150, which means it’s 50 percent less efficient than a 2006-code-built home, Ferrell noted.
Local utility companies encourage builders to construct energy-efficient homes, Kelly [of LGI Homes] pointed out. “The building codes have improved but the utility company rebates have really had a big impact on the homebuilders. The best rebate programs challenge the builders to deliver a new home that is anywhere from 10 to 30 percent more efficient than a typical home.”
