LCA results & interpretation WASHLET® S7
Scope and summary
- Cradle to gate
- Cradle to gate with options
- Cradle to grave
Functional unit
One electronic bidet seat used in an average residential environment over the estimated service life of the building. The expected service life (ESL) of a building is 75 years, and all use stage activity and impacts are accounted for in that full ESL period. The reference service life (RSL) of the bidet seat is 15 years, which is an industry-accepted average lifespan based on the economic lifespan of the product.
Maintenance
The bidet seat requires periodic cleaning, and each cleaning event uses 0.34 fl oz (10mL) of a 1% sodium lauryl sulfate (SLS) solution. The seat and lid are assumed to be cleaned twice a month, the electric plug/cord and gap between the toilet tank and seat monthly, the deodorizing filter monthly, the wand weekly, and the water filter parts every six months. The deodorizing filter and water filter are assumed to be fully replaced once every ten years, and the battery is assumed to be replaced every six years.
The waste activities associated with the disposal of old filters are included.
Repair and replacement
The lid assembly, lid bumpers, seat bumpers, deodorizer assembly, air filter, and flexible hose assembly are assumed to be fully replaced once during the 15-year RSL period as part of regular repairs. At the end of its RSL, the bidet seat is assumed to be replaced. Therefore, an additional 4 products are included as replacements, with all life cycle modules considered, over the building's ESL of 75 years. The waste activities associated with the disposal of replaced parts are included.
Manufacturing data
Manufacturing data has been collected and compiled for TOTO Malaysia.
Data reporting period: 2023.
What’s causing the greatest impacts
All life cycle stages
The use stage [B1-B7] dominates the results for all impact categories. The product replacement module [B4] dominates the results for all impact categories except for global warming and fossil fuel depletion, due to the necessity to consider an additional four products as replacements. Operational energy use [B6] contributed the most to global warming and fossil fuel depletion due to the electricity required for bidet seat operations. All life cycle modules are considered throughout the estimated service life (ESL) of the building, which is 75 years. The production stage [A1-A3] itself is slightly significant but does not dominate in any impact category. Additionally, the processes associated with dismantling the product and final waste treatment during the end-of-life stage do not have a significant impact.
Production stage [A1-A3]
The electronics contained in the bidet seat dominate all impact categories in the production stage. Other raw materials contributed a total of only ~20% of the impacts in A1. The assembly of the bidet seat in the product manufacturing stage contributed an insignificant amount compared to raw material extraction and preprocessing.
Construction stage [A4-A5]
Distribution of the product dominates impacts in the construction stage. Transportation by sea for delivery to distribution centers contributes the most, accounting for about 9% of potential smog impacts and 6% of potential acidification impacts. Transportation contributed less than 4% to the remaining impact categories.
Use stage [B1-B7]
Product replacements dominate impacts in the use stage. The use stage itself dominates most impact categories due to the consideration of an additional four products as replacements. Operational energy use [B6] leads the impacts in terms of global warming (~57.2%) and fossil fuel depletion (~57.3%). Electricity used for bidet seat operations, with a mix of peak and nominal power consumption during each use for the entirety of the building's lifetime, contributes highly to those impact categories.
Operational water use [B7] also shows significant impacts to the overall life cycle, mainly in eutrophication (~35.0%), carcinogenics (~15.1%), non-carcinogenics (~15.0%), and ecotoxicity (~5.5%).
End-of-life stage [C1-C4]
The transportation to landfill dominates impacts in the end-of-life stage. Transportation and the processes for dismantling the product contribute to a relatively low portion (<1%) of total results for all impact categories.
Operational energy and water use
Operation of the bidet seat requires electricity and water. As the bidet seat starts up, it uses a peak wattage of 1,446 W for 30 seconds for seat heating, nozzle spraying, and water heating. Then it uses 71.6 W for seat warming for the remaining 12 minutes of operation. This use stage electricity was modeled using a United States grid mix.
The incoming municipal tap water is used for rear cleansing, rear soft cleansing, front cleansing, and wide front cleansing at an average of 0.095gpm. The duration of each use is assumed to be 0.58 minutes at four uses per day. The bidet seat also features pre-misting and post-misting, plus automatic misting every eight hours.
Over the building's ESL of 75 years, the bidet seat is used 109,500 times, consuming 10,586 gallons of water. An electricity factor of 0.000961 kWh per liter of water is used to represent energy for upstream municipal water collection, treatment, supply, and downstream management.
How we're making it greener
TOTO’s Washlets are ecology-minded bidet seats that can save 50% of toilet paper consumption or more. Washlets deliver a concentrated stream of water for washing, which greatly facilitates cleaning. TOTO's wonder wave water stream delivery also enhances cleaning efficiency. As a result, not only is saving toilet paper an economic advantage, but less toilet paper use means less water, energy, and other toxic chemicals used upstream in the toilet paper production process. Additionally, only one-eighth of a gallon of water per minute is used in a maximum mode saving water over conventional bidet fixtures. Moreover, this fully eliminates the need for flushable wipes which create an added burden on toilet flushing, pipe clogs, and downstream water treatment at sanitation plants.
LCA results
| Life cycle stage | Production | Construction | USE | End of Life |
|
Information modules: |
(X) A1 Raw materials | (X) A4 Transportation/ Delivery | (X) B1 Use | (X) C1 Deconstruction/ Demolition |
| (X) A2 Transportation | (X) A5 Construction/ Installation | (X) B2 Maintenance | (X) C2 Transportation | |
| (X) A3 Manufacturing | (X) B3 Repair | (X) C3 Waste processing | ||
| (X) B4 Replacement | (X) C4 Disposal | |||
| (X) B5 Refurbishment | ||||
| (X) B6 Operational energy use | ||||
| (X) B7 Operational water use | ||||
 |
 |
 |
 |
SM Single Score
Learn about SM Single Score results| Impacts per bidet seat | 1.82E+01 mPts | 3.41E+00 mPts | 1.59E+02 mPts | 7.82E-02 mPts |
| Materials or processes contributing >20% to total impacts in each life cycle stage | Printed wiring board production as well as other raw material extraction and preprocessing. | Transportation of the product to distribution centers and disposal of packaging. | Amount of electricity used during operation and the number of product replacements needed over the building's service life. | Transport to waste processing and disposal of material flows transported to a landfill. |
TRACI v2.1 results per functional unit
| Life cycle stage | Production | Construction | USE | End of Life |
Ecological damage
Human health damage
Additional environmental information
| Impact category | Unit | ||||
| Carcinogenics | CTUh Comparative Toxic Units of Human cancerous toxicity Carcinogens have the potential to form cancers in humans. |
2.83E-06 | 2.89E-08 | 1.80E-05 | 3.43E-09 |
| Non-carcinogenics | CTUh Comparative Toxic Units of Human non-cancerous toxicity Non-Carcinogens have the potential to causes non-cancerous adverse impacts to human health. |
5.92E-05 | 2.22E-06 | 3.64E-04 | 5.14E-08 |
| Ecotoxicity | CTUe Comparative Toxic Units of Ecotoxicity Ecotoxicity causes negative impacts to ecological receptors and, indirectly, to human receptors through the impacts to the ecosystem. |
4.40E+02 | 3.10E+01 | 2.26E+03 | 6.22E-01 |
| Fossil fuel depletion | MJ surplus Mega Joule, lower heating value Fossil fuel depletion is the surplus energy to extract minerals and fossil fuels. |
1.65E+02 | 1.07E+02 | 3.19E+03 | 1.39E+00 |
References
LCA Background Report
Life Cycle Assessment of TOTO WASHLET® S7, 2024; SimaPro Analyst 9.6; ecoinvent and Industry data 2.0 databases; TRACI 2.1.
ISO 14025, “Sustainability in buildings and civil engineering works -- Core rules for environmental product declarations of construction products and services”
ISO 21930:2017, "Sustainability in Building Construction — Environmental Declaration of Building Products" serves as the core PCR along with Sustainable Minds Part A.
SM Part A: LCA calculation rules and report requirements, version 2023
August, 2023. PCR review conducted by the Sustainable Minds TAB, [email protected].
SM Part B: Electronic bidet seats, v1.0
March, 2024. PCR review conducted by Jack Geibig, Chair (Ecoform) [email protected]; Hugues Imbeault-Tétreault, ing., M.Sc.A. (Groupe AGÉCO); Rebe Feraldi, LCACP, CLAR (Pacific Northwest National Laboratory).
Download PDF SM Transparency Report/EPD
SM Transparency Reports (TR) are ISO 14025 Type III environmental declarations (EPD) that enable purchasers and users to compare the potential environmental performance of products on a life cycle basis. They are designed to present information transparently to make the limitations of comparability more understandable. Environmental declarations of products that conform to the same PCR and include the same life cycle stages, but are made by different manufacturers, may not sufficiently align to support direct comparisons. They therefore cannot be used as comparative assertions unless the conditions as defined in ISO 14025 Section 6.7.2. ‘Requirements for Comparability’ are satisfied. In order to support comparative assertions, this EPD meets all comparability requirements stated in ISO 14025:2006. However, differences in certain assumptions, data quality, and variability between LCA data sets may still exist. Any EPD comparison must be carried out at the building level per ISO 21930 guidelines, use the same sub-category PCR where applicable, include all relevant information modules, be limited to EPDs applying a functional unit, and be based on equivalent scenarios with respect to the context of construction works. Some LCA impact categories and inventory items are still under development and can have high levels of uncertainty. To promote uniform guidance on the data collection, calculation, and reporting of results, the ACLCA methodology (ACLCA 2019) was used.
SM Transparency Report (EPD) 