Sekisui Heim Smart Houses: Latest technology trends
Masato Oota

Doctor of Engineering
General Manager & Fellow
Marketing Department
Management Strategy Division
Housing Company
Sekisui Chemical Co. Ltd.

1. Introduction

2. Sekisui Heim Deployment Achievements

As of November 9, 2021, 144 countries, including Japan, havepledged to achieve carbon neutrality by 2050. In April 2021, Japandeclared that it would aim to “reduce its greenhouse gas emissions
by 46% in 2030 compared to the level in 2013 and continue its
efforts to meet the lofty goal of cutting its emission by 50%” at themeeting of Japan’s Global Warming Prevention Headquarters, aswell as at the 2021 Leaders’ Summit on Climate. In particular, thetarget set for the household sector is the highest among all sectors
at about 66% (Figure 1). Energy-saving measures in the household
sector include improving insulation performance, improving
the efficiency of equipment through the Top Runner Program,and providing information on energy-saving equipment andenergy-saving measures. Japan is also promoting the constructionof net zero energy buildings (ZEB) and net zero energy houses(ZEH), which are designed to reduce the annual primary energy
consumption to net zero through the use of solar power and otherrenewable energy sources. In addition to energy conservation
through solar power generation and high thermal insulation,
the government is also urging captive consumption through theintroduction of storage batteries, electric vehicles (EVs), and heatpump water heaters to improve grid stability and resilience forrenewable energy, which fluctuates depending on the weather, andprovide added value to residents (according to the Sixth Strategic
Energy Plan (Draft) announced on July 21, 2021).

Given this situation, Sekisui Chemical has placed priority on
the resolution of environmental and other social issues and theestablishment of a solid management foundation as the driversof future business growth through its Sekisui Heim brand ofhouses, promoting ESG management by balancing customer
value and business value. To achieve a balance between economic
efficiency and environmental friendliness, the company has beenproactively proposing the use of photovoltaic power generation
systems (hereafter referred to as “PV”) in its houses since 1997.
In 2012, it launched the “Smart Heim” house equipped withPV, home energy management system (HEMS), and household
storage battery. Further, in 2018, it adopted the ZEH standard as
the standard specification for its houses. In particular, 『ZEH』(ZEH with square brackets), which ranks highest in terms ofenvironmental contribution among its ZEH lineup, has been themost popular among house owners (Figure 2).
Sekisui Chemical has been promoting the use of renewableenergy in detached houses for 25 years, providing a total of morethan 229,000 PV houses＊1 since 1997 (Figure 3). The total
installed PV capacity has reached more than 1.25 M kW＊2, witha total annual power generation equivalent to the annual electricalenergy consumption＊3 of municipalities with a population of
500,000 (e.g., Tottori Prefecture and Hachioji City, Tokyo). This
has resulted to reduction in CO2 emissions by approximately■ Figure 1: CO2 reduction targets in the household sector■ Figure 2: ZEH categories

Reference: “ Plan for Global Warming Countermeasures” (Draft)published July 26, 2021

＊1 Number of PV houses sold, including new and renovated units, as of the end of March 2022 (based on our research).
＊2 Total installed PV capacity for all PV contracts, including new and renovated units, up to FY2021 (based on our research).
＊3	Electrical energy consumption was calculated from the national average in the “Household Energy Consumption (FY17)” report by the Ministry of the Environment. (Energy consumption does
not include gas or kerosene usage.)10

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■ Figure 3: Cumulative number of Sekisui Heim houses
equipped with PV■ Figure 5: Sekisui Heim ZEH deployment record (FY2021)

386,000 tons per year＊4, which is equivalent to CO2 absorption
by approximately 27 million cedar trees＊5 and to afforestation of
more than 31,000 hectares of land, an area similar to the artificial
forest area in Tokyo (ca. 35,000 hectares)＊6.
Along with the uptake of PV, early on, we have focused on
the spread and promotion of ZEH. Performance equivalent to thehighest rating (ZEH level) for the thermal insulation performance
rating and primary energy consumption rating, which were
newly established in April 2022 under the Housing Performance
Indication System, has been incorporated as part of the standard
specifications of Sekisui Heim houses in 2018＊7. Recognizingat the outset the growing need for energy conservation in thefuture, we have continued to propose ZEH to our customers.
In particular, we are focusing on the promotion of 『ZEH』,
which ranks highest in the ZEH series in terms of environmentalcontribution, setting a record high of 82%＊8 deployment ratio
for『ZEH』in FY2021. The overall deployment ratio for ZEH＊9
was 89% (Figures 4 and 5).

『ZEH』is designed to reduce primary energy consumption
by 100% or higher than the standard primar y energ yconsumption＊7, in addition to use of PV and other renewableenergy sources, whereas “Nearly ZEH” is designed to reduce
primary energy consumption by 75% or higher, and “ZEHOriented” by 20% or higher, excluding use of renewable energy.
Also, we are actively working to develop and popularize“energy self-sufficient houses”＊10 equipped with storage batteries
in response to rising energy prices and supply instability, as well as
to enable resilience against frequent natural disasters. The storage
battery deployment ratio in sales of newly built detached houses
increased for the fourth consecutive year, reaching 72% in fiscal
2021 at 47,000 houses in total＊11 (Figure 6). Going forward, wewill continue to promote the uptake of “energy self-sufficienthouses” along with『ZEH』.

■ Figure 4: Trends in Sekisui Heim ZEH deployment ratios■ Figure 6: Trendsin storage battery deployment ratio andtotal installed units＊4＊5＊6＊7 ur calculation was based on the installed PV capacity for all PV contracts, including new and renovated units, up to FY2021.
O
Our calculation for cedar tree conversion was based on data from the Kanto Regional Forest Office.
The artificial forest area in Tokyo was based on the Natural and Artificial Forest Ratios by Prefecture (as of March 31, 2017) published by the Forestry Agency (MAFF).
Standard specifications were refined to meet the national ZEH external standard UA value of 0.6 or less (Regions 4 to 7). Depending on the plan, this may not be achieved if theopenings are too large.
＊8 『ZEH』 deployment ratio was aggregated based on the ZEH Builder reporting method.
＊9 In addition to『ZEH』, ZEH includes Nearly ZEH and ZEH Oriented models. ZEH deployment ratio was aggregated based on ZEH Builder reporting method.
＊10 Not all the electricity can be supplied. There is still a need to purchase power from a utility company.
＊11 This deployment ratio represents the contract-based deployment ratio for storage batteries (including V-to-H) from April 2021 to March 2022, and the cumulative number is the total
number of houses sold, including new and renovated units, as of the end of March 2022 (based on our research).

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113. Project with the Ministry of the Environment

The Ministry of the Environment implemented a project on“Development and Demonstration of Technologies Promoting
CO2 Emission Control Measures” in FY2021 (name changed
to “Development and Demonstration of Carbon Neutral
Technologies through Regional Co-Creation and CrossSectoral Collaboration” in FY2022), with priority theme (1)“Development, demonstration, and cost reduction of energy
self-sufficient decarbonized housing modules for dealing withworsening disasters and infectious diseases.” Under this project,
the “Development and Demonstration of Energy Self-Sufficient
Housing Units” Technology Development and Demonstration
Theme presented by Sekisui Chemical Housing Company incollaboration with Nichicon Corporation, the Central ResearchInstitute of Electric Power Industry (CRIEPI), and the Universityof Tokyo Institute of Industrial Science (IIS) was adopted by
the Ministry of the Environment in April 2021 (Figure 7). As
the representative business operator of this project, we started
technological development together with the three collaborators
in June 2021. With the “New Smart Power Station FR
GREENMODEL” (hereinafter, “New Green Model”) launchedin October, we conducted evaluation and verification throughtest house users to further enhance and spread this technology forpromoting energy self-sufficiency. Test houses based on the “NewGreen Model” released in October 2021 were also equipped withhigh-capacity PV, e-PocketGREEN (Tribrid Energy Storage
System), HEMS, and ventilation and air conditioning systems for
all rooms. Test house users have started to move in to the “NewGreen Model” houses from around April 2022. We have collected
electricity data via HEMS starting with users that have already

moved in and will interview and survey them after they haveactually lived in the houses.
Achieving a decarbonized society by 2050 entails the active
utilization of clean PV power and the promotion of an energy
self-sufficient＊10 lifestyle that avoids the purchase of electricity asmuch as possible. In this project, we will acquire and analyze dataon the amount of electricity used in real life and determine howmuch reduction in CO2 emissions can be achieved using houses
equipped with high-capacity PV and with the high-capacity
storage battery “e-PocketGREEN,” which were developed toachieve this lifestyle. e-PocketGREEN has a storage capacity of12 kWh, which is about twice the capacity of conventional storage
batteries＊12. It also enables high output (4 kVA) even in the eventof a power outage. It uses a power conditioner with a Tribrid
specification that enables linkage with the V-to-H system sothat the combined use of EV further increases the power storage
capacity. In both normal times and during power outages, power
generated by the high-capacity PV can be stored and consumed
independently (Figure 8). In addition, both the storage battery■ Figure 8: Menu of systems installed at test houses anditems for evaluation and demonstration■ Figure 7: Evaluation and demonstration flow in the project andvision for future deployment＊12	Calculated from the storage capacity of the battery with the highest shipment volume, based on the “Net Zero Energy House Support Project Research Conference 2020” conducted by theAgency for Natural Resources and Energy, Ministry of Economy, Trade and Industry (METI). Storage battery capacity of 12 kWh is the catalog value and is different from the actual usablecapacity.

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and power conditioner can be installed at high places to prevent
damage from flooding. The V-to-H system enables saving spaceby separating the V-to-H stand and the V-to-H pod that connects
to the EV, making it easy to install the equipment in parking
spaces. We will also collect feedback from the test house users andevaluate the resilience and convenience of installing these systems.
To realize a high-quality indoor environment, whichis indispensable for living in the new normal, in June 2021,
we developed the “Comfortable Airy T-SAS” ventilation andair conditioning system that provides the three functions ofventilation, air conditioning, and dust purification for all rooms.
For the second layer of the high-performance three-layer filter,
we used a HEPA filter that can capture 99.97% of pollen and fineparticles 0.3 μm or larger＊13 on a first-class ventilation system
for stably performing both exhaust and intake mechanically. For
the air-conditioning filter installed in the indoor air intake vent,
we used an antiviral filter＊14 that uses the antivirus processing
agent Viru-taker™. In this project, with the technical cooperationof the National Institute of Advanced Industrial Science andTechnology (AIST), we will verify the effectiveness of indoor
air purification and thermal performance using these advanced
technologies in comparison with generic systems (air conditioner
heating and cooling and third-class ventilation) through actual
measurements (Figure 9). We will also evaluate and verify therelationship between health and performance through user surveys
and interviews.
To encourage energy-saving actions and reduce CO2 emissions
in daily life, we have standard-installed HEMS (Smart HeimNavi) to approximately 66,000 houses to date. In addition toanalyzing the electricity usage data of these HEMS-equippedhouses and providing energy-saving consulting services tailoredto each house, we also included remote control and voice control
functions for household equipment (lighting, EcoCute system,air conditioning, etc.), further enhancing daily life convenienceand reinforcing awareness on energy-saving behaviors. To
reduce CO2 emissions by further improving the convenienceof HEMS, we will develop a new application for smartphones.
We will create an “integrated user interface” to control homeequipment and appliances and verify its usability. Initially, wewill pre-release the application to owners of Sekisui Heim houses
already equipped with HEMS to investigate and analyze energysaving behavior during the winter (heating period). We will thenimprove the application from the results of the analysis. Next, wewill also verify the operation of the system during the summer(cooling period) through questionnaires and interviews, including
test house users. Further, we will improve and re-evaluate theapplication to enhance the integrated user interface.

■ Figure 9: High-performance ventilation system and integrated user interface
configuration diagram＊13 Pollen particle size was assumed to be 10 μm or larger, based on collection rate measurement results for atmospheric dust between 0.3 and 0.5 μm (based on research by Toray Industries,Ltd.). The value shows the initial performance of the filter at the time of delivery. It may be lower depending on the customer’s environment and other usage conditions. The filter needs to bereplaced (for a fee) once every five years (guide) to ensure performance. The value may be lower depending on the customer's environment and other usage conditions. It is not intended totreat or improve hay fever or respiratory diseases.
＊14	Tested on the basis of JIS standards (JIS L 1922:2016 (ISO 1818184) for suppression of viruses attached to the filter. The filter is not effective against all viruses. It is not intended to cure,improve, or prevent disease. Also, the antiviral function for air passing through the filter has not been tested.

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4. Latest Sekisui Heim Smart House

In anticipation of the risk of power outages due to frequent
natural disasters, since 2012, Sekisui Chemical has beenproactively proposing energy-self-sufficient houses＊10, which
are equipped with storage batteries and are aimed at enabling alifestyle that avoids the purchase of electricity as much as possible.
In 2021, we launched the New Green Model, the latest smart
power station house model equipped with the newly developed
high-capacity storage battery e-PocketGREEN＊15 and can supply
approximately 73% of annual electricity consumption (equivalentto 260 days)＊16 with clean PV that does not emit CO2 during
power generation. In addition, we opened GREENMODEL
Park showrooms in 20 locations nationwide where customers
can have a hands-on experience of eco-friendly living in full-size
homes, strengthening our proposal capability for energy-selfsufficient homes (equipped with storage batteries). We recently
made proposals in anticipation of the risk of rising energy prices
due to geopolitical factors. As a result, we were able to convince
many customers of the importance of balancing environmental
contribution and economic efficiency and having a reliable energy
supply in times of disaster＊17. This led to a significant increase in
the number of GREENMODEL houses ordered in the second
half of fiscal 2021 to 280%＊18 compared to the previous year.
Consequently, the storage battery deployment ratio in sales of
newly built detached houses increased for the fourth consecutive
year to a record high of 72%. We have installed storage batteries toa total of more than 47,000 houses since 2012.

5. Conclusion

As a leading sustainable housing company, we are committed
to contributing to the reduction of environmental impact throughthe further promotion of 『ZEH』 and energy self-sufficienthouses＊2 (equipped with storage batteries). The smart housemarket, however, is still at an early stage of development andpenetration. The nationwide penetration rate of ZEH in Japanis only 20% in 2020, both for custom-built and built-for-salehouses (calculated from the Sustainable open Innovation Initiative(SII) “Net Zero Energy House Demonstration Project Research
Conference 2021” presentation material), pointing to an urgent
need to increase penetration. Further, since this is only for thenew detached house market, there is a need to also promote thepenetration of ZEH in the new housing complex and housing
stock markets. Also, collaboration and advancement of IoT
devices centered on HEMS will also be crucial in the evolutionof environment-friendly housing. This includes the automationof energy control, UI-based operation of home appliances andequipment, advancement of display systems, and the provision ofdata utilization businesses and services. Industry-wide co-creation
to drive this evolution and penetration is needed to maximize theadvantages for homeowners early on and accelerate the speed ofpenetration, both for new and existing houses.
References[1]	Press Release: Start of demonstration of the latest Sekisui Heim “Smart & Resilient”
Technology, October 29, 2021, Sekisui Chemical Co., Ltd.
[2]	Press Release: 『ZEH』, which ranks highest in terms of environmental contribution in theZEH series of newly built detached houses, reaches a new record high of 82% deployment
ratio in FY2021, April 25, 2022, Sekisui Chemical Co., Ltd.

＊15 e-PocketGREEN was jointly developed with Nichicon Corporation.
＊16	[Calculation conditions] Building site: Nagoya; Power contract: Chubu Electric Power Co., Inc.; fully electrified; PV capacity, 9.72 kW; storage battery capacity, 12 kWh (green mode), airconditioning system in all rooms (Comfortable Airy (1st floor); EcoCute system; total floor area: 121 m2, UA value: 0.54; electricity usage: calculated based on HEMS data in an actual house.
This value may not be reached depending on the environment and other usage conditions.
＊17	Electricity can be used even in the event of a power outage only if the amount of PV power generated or the remaining charge of the storage battery exceeds the usage or output volume.
Some equipment may not be available depending on the weather, season, usage volume, and simultaneous usage (output) volume. Electricity cannot be used if the storage battery is empty.
＊18 Ratio of the number of GREENMODEL house contracts in 2H FY2020 and 2H FY2021 (based on our research).

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