In recent years, energy efficiency labels for residential buildings have begun appearing in advertisements for new properties. These labels indicate a building's energy efficiency and are designed to allow consumers to quickly understand and compare the energy efficiency of homes when purchasing or renting. The aim is to make it easier for consumers to choose energy-efficient homes, thereby promoting the widespread adoption of such homes across the market. In particular, from April 2024, it will be mandatory to display this label in advertisements for new homes, and energy efficiency will become an increasingly important factor in choosing a home.
Homes with high energy efficiency consume less energy for heating and cooling, which ultimately leads to savings on utility bills. With electricity and gas prices continuing to rise, homes that can keep monthly utility bills low offer significant benefits for household budgets. Furthermore, well-insulated homes maintain stable indoor temperatures throughout the year, effectively preventing heat shock in winter and condensation, thereby providing a comfortable and healthy living environment. For these reasons, energy efficiency labels are gaining attention as a new standard in home selection.
There are several types and indicators of energy efficiency labels. The following are some of the most representative ones.
These indicators are all based on national standards and are reliable evaluation criteria. Thermal insulation performance grades and primary energy consumption grades are based on the Housing Performance Display System (Housing Quality Assurance Act), while BELS is a third-party certification system based on the Building Energy Conservation Act. Although the evaluation methods and display formats differ, they share the common feature of “visualizing energy efficiency performance through numerical values and stars.”
What exactly is displayed on the actual energy efficiency labels? Labels that will appear in advertisements and brochures for newly constructed homes starting in 2024 are divided into two main categories: energy consumption performance (star rating) and thermal insulation performance (grade display). Optional information such as annual estimated utility costs and ZEH achievement status may also be included. We will explain how to interpret each of these.
The above are the main points of the label information. In summary, by checking the “number of stars,” “thermal insulation grade,” “annual utility costs,” and “ZEH achievement check,” you can roughly understand the energy efficiency of the residence. In particular, the number of stars and the thermal insulation grade are key indicators that succinctly demonstrate the energy efficiency and thermal insulation of a residence, so these should be the first points to focus on.
Energy efficiency labels are issued in accordance with public standards and rules, and their reliability is high. The basis for evaluation is the national standards such as the “Energy Conservation Standards” and the “Residential Performance Display Standards.” Specifically, the BEI (Building Energy Index), which is an evaluation indicator for energy consumption performance, is calculated as the ratio of the designed primary energy consumption to the national standard primary energy consumption. This objectively shows “how much energy can be reduced compared to the standard,” and the number of stars is assigned based on the BEI value. For example, BEI=1.0 corresponds to two stars (meeting the standard), and BEI=0.8 corresponds to three stars (20% reduction compared to the standard).
Additionally, insulation performance grades and primary energy consumption grades are evaluated as part of the Housing Performance Labeling System under the Housing Quality Assurance Promotion Act (Housing Quality Act). These are official evaluation criteria for housing performance, alongside seismic resistance grades, and are determined by housing companies or third-party organizations through prescribed calculation standards and review procedures. The grade standards themselves are established by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), with detailed benchmark values set to account for regional climate conditions. For example, to claim a thermal insulation grade of 5, all walls, ceilings, windows, etc., must meet or exceed the specified thermal insulation performance standards, and this cannot be claimed arbitrarily.
Third-party evaluation (BELS) further enhances credibility. BELS certification is an official certification issued by evaluation agencies registered with the Minister of Land, Infrastructure, Transport and Tourism (MLIT), which are private third-party organizations. Evaluation bodies strictly adhere to rules set by organizations such as the Energy Efficiency Performance Evaluation and Labeling Association, minimizing the possibility of arbitrary or lenient evaluations. On the other hand, even self-evaluation labels, as long as they are calculated in accordance with the government-provided web program, follow the same basic evaluation methods. Therefore, the numbers and star ratings listed on the label are based on uniform standards and can be considered reliable information.
In summary, energy efficiency labels for homes are similar to energy efficiency labels for appliances (such as the number of stars or APF values), serving as a “residential version of an energy performance certificate” based on public standards. They are designed to provide reliable information for home buyers and renters.
When searching for a home, be sure to check the energy efficiency labels. Especially when purchasing a new single-family home or apartment, the label should be displayed in the brochure or on the website. For rentals, you can check the label on recruitment flyers or real estate portal sites for new apartments or buildings. Below, we summarize specific checkpoints to consider when reviewing energy efficiency labels as part of the “Key Points for Choosing a Home.”
By utilizing the energy efficiency label, you can objectively determine which home is more eco-friendly and cost-effective. When selecting a home, considering not only location, floor plan, and price but also energy efficiency will help you choose a home that will provide long-term satisfaction.
The insulation performance indicated by the energy efficiency label and the primary energy consumption (energy consumption performance) are closely related. In simple terms, improving insulation performance is the foundation for reducing energy consumption.
In a house with poor insulation, even when heating is turned on in winter, heat escapes quickly, making it difficult to warm up properly or stay warm. In summer, if cool air from air conditioning leaks out, it becomes less effective, and if hot outdoor air enters, the indoor temperature may not drop easily. As a result, air conditioners or heaters must run for longer periods, increasing energy consumption. In other words, poor insulation performance leads to higher energy consumption = higher utility bills.
Conversely, homes with high insulation performance ratings maintain heating and cooling effects for longer periods. A little heating keeps the warmth inside, and cooling keeps the coolness inside, allowing you to reduce the runtime and output of air conditioners. As a result, primary energy consumption throughout the year is also reduced. The star rating on energy efficiency labels (energy consumption performance) is determined by a combination of factors, including insulation performance, equipment efficiency, and the presence of solar power generation. However, insulation performance is one of the most critical factors. To put it simply, even if an air conditioner is highly efficient, a poorly insulated house will waste energy. Conversely, even if the equipment is average, a well-insulated house will significantly contribute to energy savings.
In fact, the establishment of insulation performance grades 5, 6, and 7 in 2022 was based on the idea that “improving the insulation performance of homes is the key to reducing CO₂ emissions and energy consumption.” Grade 7 (equivalent to HEAT20 G3) is said to be capable of reducing heating and cooling energy by approximately 40% compared to Grade 4, and a home with such high performance would likely achieve the highest star rating. Before generating energy through renewable energy systems like solar power, it is crucial to first reduce energy consumption itself through energy conservation (insulation and efficiency).
In summary, insulation performance and primary energy consumption are two sides of the same coin. Homes with higher star ratings on energy efficiency labels generally have higher insulation performance grades. When choosing a home, it is ideal to focus on the balance between the two and opt for a home that is both well-insulated and equipped with high-efficiency systems.
Living in an energy-efficient home has positive effects on both household finances and health.
First, regarding the impact on utility bills, the difference becomes significant over the long term. For example, comparing a home with low energy efficiency (two stars, grade 4) to one with high energy efficiency (four stars, grade 6), the annual energy consumption difference can amount to thousands of kWh. The corresponding electricity and gas costs are literally wasted expenses. With a high-performance home, such waste can be eliminated, potentially saving tens of thousands of dollars annually and hundreds of thousands over 10 to 20 years. The money saved can be used for other living expenses or leisure activities, and if you install solar panels to sell excess electricity, it is not just a dream to achieve zero utility bills but also to generate income.
Next, the impact on living environment (livability). Homes with high insulation performance are easier to maintain a comfortable indoor environment that is warm in winter and cool in summer. A home with small temperature differences indoors offers health benefits as well. Heat shock (sudden changes in blood pressure caused by extreme temperature differences) occurs when moving from a warm living room to a cold bathroom during the winter. This is a serious issue in Japanese homes, affecting many elderly people annually. However, in highly insulated homes, maintaining a consistent temperature throughout the house can significantly reduce the risk of heat shock. Additionally, reduced condensation helps prevent mold and dust mites, which can alleviate asthma and allergies. According to government data, energy-efficient homes with high insulation, airtightness, and high-efficiency equipment are not only economically advantageous in terms of utility costs but also provide residents with a comfortable, healthy, and safe living environment. Homes with high energy efficiency truly enhance the quality of life.
Another important aspect is their contribution to the environment. Homes with high energy efficiency emit fewer CO₂ emissions and contribute to mitigating global warming. CO₂ emissions from the residential sector account for an increasingly significant proportion of total emissions each year. However, if each individual lives in an energy-efficient home and reduces energy consumption, this directly contributes to achieving carbon neutrality for society as a whole. The fact that energy-efficient homes provide both personal benefits, such as reduced utility bills, and public benefits, such as environmental conservation, makes them a choice that is “good for both you and the planet.”
Finally, let's summarize the key points of this article.
The energy efficiency label is a tool that makes the energy efficiency and insulation performance of a home “visible.” Based on the number of stars, insulation performance rating, and estimated utility costs, consumers can intuitively understand how energy-efficient and economical a home is. It is a reliable indicator based on national regulations and has become essential information for choosing a new home starting in 2024.
By effectively utilizing energy efficiency labels, you can make a wise choice for your home, considering future utility costs and living comfort. While high-performance homes may seem more expensive at first glance, they often pay for themselves in the long run through utility cost savings and improved health and comfort. Be sure to check the labels at model homes or property websites and pay attention to the number of stars and energy consumption differences. When comparing options, recall the points mentioned in this article (star ratings, insulation performance grades, estimated utility costs, etc.), and feel free to ask the sales representative any questions you may have.
The homes where we spend our daily lives account for a significant portion of energy consumption. By using the energy efficiency label as a guide, you can find an economical and environmentally friendly ideal home or room. This will surely be the first step toward a comfortable lifestyle and a sustainable future.