From triple pane windows to state of the art HVAC systems, residential construction has made significant advancements towards enhanced energy efficiency over the last few decades. Concerned about their carbon footprints, both homeowners and local governments across the US have made energy efficiency a clear priority in recent years. Today, energy efficient appliances, finishings and building materials are all must-haves for home buyers -- especially those in California. In a June 2021 article for the Philadelphia Inquirer, Michaelle Bond noted that “nearly two-thirds of Realtors surveyed in March said the promotion of energy efficiency in listings could help attract buyers.” According to a report issued by the National Association of Realtors, more than half of the realtors surveyed “said their clients were interested in sustainability, and nearly a third reported they were involved in the buying or selling of a property with “green” or eco-friendly features in the last 12 months.” Quoting NAR VP of Demographics and Behavioral Insights Jessica Lautz, Bond wrote that “‘a growing number of consumers are seeking homes with features that are good for the environment and, by extension, good for their wallets by reducing utility expenses in the long run.’” Though many of the most energy efficient homes employ innovative technologies, others employ traditional building techniques. From Spanish-style architecture to insulated concrete forms, follow below to learn about five surprising energy efficient house designs.
Installing Energy Star Certified appliances is not the only way -- nor the best way -- to ensure your home is both comfortable and energy efficient. The most effective way to ensure your home is energy efficient is to prioritize energy efficiency during the home building process. In their resource “Elements of an Energy-Efficient House,” the US Department of Energy National Renewable Energy Laboratory (NREL) outlines the five determiners of energy efficiency. These five basic elements are “a well-constructed and tightly sealed thermal envelope, controlled ventilation, proper size, high-efficiency heating and cooling systems and energy-efficient doors, windows and appliances.”
For those unfamiliar with the term, a home’s thermal envelope is “everything about the house that serves to shield the living space from the outdoors.” This includes everything from the home’s “wall and roof assemblies” to its insulation and windows. To create a tight thermal envelope, the DOE recommends insulating concrete forms (ICF) -- one of the methods on this list -- for construction of the home’s walls and roof. Not only are ICF homes efficient, but they are also “very strong and easily exceed code requirements for areas prone to tornadoes or hurricanes.” To learn about four additional energy efficient house designs, continue reading.
Living in a state prone to record-breaking heat waves in the valleys and frigid winters in the mountains, California homeowners are always looking for ways to increase energy efficiency while lowering costs. Californians also care deeply about the impact their energy usage has on the environment. In fact, Vivint Solar’s 2018 Environmental Consumer Survey found that “Californians are the most eco-conscious shoppers in the country, [with] over 2 in 5 Californians (42 percent) considering the environment before every purchase.” An article from PR Newswire quoting Vivint Solar CEO David Bywater noted that “‘their commitment to clean, renewable energy’” proves Californians care about the environment. According to Bywater, “Californians set the standard for environmentally conscious living.’"
As such, it should come as no surprise that the California Energy Commission recently updated building codes to reflect the state’s values. In an August 2021 article for The New York Times, Ivan Penn explains these recent changes. Penn writes that California state regulators recently updated the building code “to require some new homes and commercial buildings to have solar panels and batteries and the wiring needed to switch from heaters that burn natural gas to heat pumps that run on electricity.” These changes represent “one of the most sweeping single environmental updates to building codes ever attempted by a government agency.” According to Penn, these updates to the building codes will apply only to new builds beginning in 2023. In doing so, the government aims to “reduce and eventually eliminate the use of fossil fuels like natural gas, replacing them with electricity generated by renewable sources like solar panels, wind turbines and hydroelectric dams.” Regulators hope these changes will also lessen operations costs for renters and property owners across California.
First on our list of energy efficient house designs is the geodesic dome home. The first geodesic dome structure was designed by engineer Walther Bauersfeld for a planetarium shortly after the First World War. It was architect and author Buckminster Fuller who actually coined the term "geodesic,” after working with Kenneth Snelson and other artists at the Black Mountain College shortly after WWII. Fuller not only patented the design but also built many geodesic dome structures across the US with the help of his students. In his article “The story of Buckminster Fuller’s radical geodesic dome” for BBC Culture, Jonathan Glancey notes that Fuller and his wife lived in a geodesic dome house in Illinois until their deaths.
Glancey writes that architects of Fuller’s time were drawn to his geodesic dome structures because they “offered the greatest volume for the least surface area, a case of doing very much more with very much less.” Despite their “sheer visual drama,” incredible energy efficiency and minimal construction costs, geodesic dome houses have yet to catch on in the US. According to Glancey, “the geodesic dome had been a slow burn in terms of everyday design, but its influence should never be underestimated.”
Unusual and a bit kitschy, most American homeowners know of geodesic dome homes only for their cult aesthetic appeal. However, the geodesic dome is also incredibly durable, even in the face of extreme weather events. According to the HomeAdvisor guide “Geodesic Domes – A Better Structure?,” “geodesic domes are the only man made structure that gets proportionally stronger as size increases.” It is the shape of the geodesic dome that makes it one of the most naturally energy-efficient designs. In her article “5 great reasons to build a geodesic dome home” for Inhabitat, Michelle Kennedy Hogan explains. Hogan writes that the “sphere is nature’s most efficient shape, covering the most living area with the least amount of surface area.”
When one compares a rectangular home to a dome-shaped home of a similar size, “the dome home will have 30 percent less surface area.” Because the dome home has thirty percent less surface area than a typical box-shaped house, “a third less heat is transferred to and from its surroundings.” This results in an average savings of “about 30 percent or more on the typical homeowner's heating and cooling bill.” In her article “Are dome homes the next big thing?” for CBS News, Ylice Glink offers an even higher estimate of cost savings. According to Glink, geodesic dome homes offer “owners savings of around 50 percent.” With such incredible cost savings, geodesic dome homes might finally catch on in coming years.
As mentioned above, the US Department of Energy National Renewable Energy Laboratory (NREL) identifies ICF construction as one of the best building methods for energy-efficient homes. In their brief “Elements of an Energy-Efficient House,” the DOE explains that this is because ICFs contribute to “a well-constructed and tightly sealed thermal envelope.” This envelope prevents heat or cold from passing from the exterior of the home into the interior while also minimizing the escape of desired warm or cool air from the interior to the exterior.
For those unfamiliar with insulating concrete forms, ICFs are lightweight insulation forms that are hollow inside. The hollows within ICFs are filled with concrete once the forms have been laid. In our recent post “Climate Change Resilient Building Materials for California Homes,” we noted that ICFs were invented in the 1960s by designer Werner Gregori, who was working as a general contractor at the time. Though ICFs were initially met with skepticism from builders, they have since become the gold standard of energy efficient home construction. Today, ICFs are commonly used in the passive house sector. The article “ICFs and the Passive House Movement” for ICF Builder Magazine supports this. According to the article, “building with ICFs offers a much easier path to net-zero status (and ultimately passive house certification as well).” Builders across the US and abroad use ICFs “to construct net-zero homes [because] ICF builds are highly energy-efficient, inherently airtight and eliminate thermal bridging.”
In her article “ICF Construction: Everything You Need To Know” for Rise, Maria Saxton notes that “ICF construction has two advantages in terms of the energy performance of the building.” First, insulating concrete forms “seal very well,” which prevents “air leakage through the walls.” The second energy performance advantage of ICF is that each form “has two continuous insulation layers, one inside and one outside, with no thermal bridges [which] reduces heat loss.” Writing for Green Home Guide in his article “How Insulated Concrete Form Works,” Zach Williams notes that “it’s common to see a reduction in energy expenditure of between 25 and 50 percent.”
ICF homes are also sustainable in other ways. According to Williams, ICF homes “use roughly 10 fewer trees than traditional buildings.” Perhaps best of all, ICF homes are famously disaster-resilient. In a recent article for ABC7, Phillip Palmer notes that ICF technology has become “a solution to California’s destructive wildfires.”
Though man and his ancestors have lived in earth-sheltered homes -- such as dugouts and caves -- for thousands of years, the practice is not as common today. Despite their lack of prevalence in the United States, earth sheltered homes are incredibly energy-efficient. As the movement towards passive house design grows, however, earth sheltered homes are expected to gain a greater following. For those unfamiliar with the term, earth sheltered homes are those whose exterior walls and/or floor are composed of or supported by earth. Walls of earth sheltered homes are often further supported by concrete or steel. The degree to which earth sheltered homes are covered by the earth varies. Some are fully submerged while others are set into the side of a hill.
According to Murrye Bernard in The Spruce article “Earth-Sheltered and Underground Homes Basics,” there are three primary forms of earth sheltered homes. These include “in-hill sheltered homes,” “underground earth sheltered homes” and “underground earth sheltered homes.” Though still relatively rare in the modern US, the Department of Energy Office of Energy Efficiency & Renewable Energy recently identified earth sheltered homes as a viable option for homeowners. According to their resource “Efficient Earth-Sheltered Homes,” if homeowners are “looking for a home with energy-efficient features that will provide a comfortable, tranquil, weather-resistant dwelling, an earth-sheltered house could be right.” We explain why below.
Quite simply, natural insulation is what makes earth sheltered homes so energy efficient. The National Concrete Masonry Association resource “Earth-Sheltered Buildings” explains that earth sheltered homes “have a lower infiltration or air leakage rate” because of their naturally sealed thermal envelope. In traditional homes, the infiltration rate may be responsible for “up to 20% of the total heating requirement.” Most of these losses occur through windows, doors and gaps between the roof and walls. Because the earth surrounding an earth sheltered house reduces the number of gaps, “these losses are effectively eliminated.”
In her article “Underground Living and Eco-Friendly Underground Homes” for Dengarden, Stephanie Marshall outlines the cost savings homeowners can expect. She writes that “using the natural insulating properties of soil, people who build their homes underground can save a substantial amount in heating and cooling.” Marshall notes that living in an earth sheltered home could “reduce cooling costs in summer and heating costs during the winter from 60-85%.”
Like geodesic dome homes, tiny homes are more energy efficient than other builds because they have less surface area. However, tiny homes are more efficient because they are smaller overall while geodesic dome houses are efficient because of their particular shape. Once considered incompatible with the average American due to their maximum four hundred square foot size, tiny homes have become much more popular in recent years. According to Brittany Chang in a December 2020 article for Business Insider, 58% of Americans would now consider living in a tiny house. Of the 2,006 Americans surveyed, “86% said they would contemplate purchasing a tiny home as their first home and 84% of those surveyed said they would consider a tiny home as a retirement living option.” In California, tiny homes have emerged as a viable alternative to stick-built ADUs -- or accessory dwelling units -- rather than primary single family homes.
The larger a room and the loftier that room’s ceiling, the more energy it takes to heat or cool the space. In her article “Are Tiny Houses Sustainable? Here's How They Can Save You Money and Energy” for Green Matters, Stephanie Osmanski notes that “by this logic, you can guess that tiny homes actually do use less energy, making less waste, and therefore making them more sustainable.” While the average American home is larger than 2,500 square feet, tiny houses range between 100 and 400 square feet of built space.
According to iProperty Management, “a tiny home uses about 7% of the energy that a traditional house does [and] moving to a tiny home can decrease a household’s ecological footprint by 45%.” Experts estimate that tiny homes only produce about 2,000 pounds of carbon emissions each year, while traditional homes produce nearly 30,000 pounds. This reduction in energy use results in huge cost savings for homeowners. Some particularly efficient tiny homes -- such as this house designed by Matt Impola -- offer their residents electricity bills as low as $15 per month.
Last on our list of surprisingly efficient house designs is the Mediterranean style home. Mediterranean style homes are still popular today, especially in California. In fact, ElleDecor writer Monique Valeris noted that “a Mediterranean house is...timeless and quintessential California.” Traditional materials like limestone, wood, terracotta and stucco feature heavily in Mediterranean style homes. While these types of homes have been built for centuries, today’s homeowners might not expect Mediterranean style homes to be so energy efficient. However, these natural materials are exactly what makes Mediterranean style houses perfect for the climate-conscious homeowner.
First, the fired clay tiles used in traditional Mediterranean style homes contribute to the durability and energy efficiency of the structure. In his article “Buying a Mediterranean Style House: Luxury Living or Not Worth the Trouble?” for Homelight, Garrett Callahan writes that the tiled roofs of Mediterranean style homes “if installed correctly, can last for decades and won’t rot like wood or potentially leak like asphalt.” Because clay tiles disperse warmth evenly across the roof of Mediterranean style homes, these roofs can “cut the transfer of peak-day heat into the home by up to 85%.” Similarly, terracotta tiles and stone floors -- which are most common in Mediterranean style homes -- can keep homes warmer during the winter and cooler during the summer. Writing for New Home Source, Sue Dario notes that “natural stone or ceramic tile may feel cold to the touch in winter...but they conduct heat and are more energy efficient than you might think.” Furthermore, tiles are especially compatible with “radiant heat sources within the floor.”
Lastly, the stucco walls of Mediterranean homes protect homeowners from high electricity bills. For those unfamiliar with stucco, Juan Rodriguez explains in his article “What Is Stucco Material?” that stucco is “made from cement, sand, and lime and hardens into a highly durable material that requires little maintenance.” The HomeAdvisor guide “Stucco Siding – Installation Considerations & Advantages” notes that “because of the application and the material, stucco is an incredible insulator of both warm and cool air.” According to HomeAdvisor, a stucco exterior makes it “cheap and easy to maintain a constant temperature in your home.” In fact, stucco’s “energy efficiency is one of the main reasons stucco is such a popular siding choice in areas of extreme heat, such as the American Southwest.”
As a local design-build firm, Element Homes is uniquely qualified to help Californians build disaster resilient, energy efficient homes that can withstand future extreme weather events. Having worked all across California -- from Los Angeles to San Francisco, Element understands how climate-conscious West Coast residents are. The Element Homes team is well-educated on all of California’s latest building codes -- especially those related to safety and efficiency. Learn more about building an energy efficient home in California with Element here.
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