On October 20, 2026, Panasonic Holdings (Panasonic HD) announced that it will start full-scale production of glass-type perovskite solar cells in April 2029, one year earlier than the originally planned fiscal 2030. The company plans to use a mass-production technology development site now under construction in Nagahama, Shiga Prefecture. At its development site in Moriguchi, Osaka Prefecture, it has already been selling early-production units since September 2026. The idea of turning windows and exterior walls into power-generating equipment is moving into a practical stage that involves product supply and installation in buildings. Before adopting the technology in an actual building, however, it is necessary to look at the differences in specifications between the early-production and full-scale products, as well as the conditions under which power generation efficiency and durability were verified. ## Full-scale production to begin in April 2029, with larger glass and wider specifications The early-production units are currently manufactured at the Moriguchi development site in Osaka Prefecture. Panasonic HD is working to build up installation and operating know-how through early deployment with customers, and then carry that over to full-scale production at the Nagahama site. The company explains that the earlier production start reflects progress in technology development, as well as rising market expectations and policy support. According to a [product specification comparison chart](https://news.panasonic.com/uploads/tmg_block_page_image/file/41219/jn261020-1-3.jpg) the company released in October 2026, the early-production and full-scale products differ in maximum glass size and supported structures. The maximum size of the early-production product is 1.8 × 1.0 m, but it is planned to expand to 1.8 × 1.2 m for the full-scale product. Currently only laminated glass is supported, but full-scale production will also offer laminated insulating glass.
| Item | Early-production product | Full-scale product (planned) | | -------------------------------- | --------------------------------------- | ------------------------------------------------------ | | Supply start | September 2026 | April 2029 | | Maximum glass size | 1.8 × 1.0 m | 1.8 × 1.2 m | | Glass type | Laminated glass | Laminated glass, laminated insulating glass | | Design processing | Possible (with some limits) | Possible (with some limits) |
*Specifications and plans as of October 2026. Subject to change. Larger glass and more available structures in full-scale production are expected to open the way to use in a wider range of windows and exterior parts of buildings. However, the specification table alone does not show whether power generation efficiency or annual output will improve. The plan is better understood as one in which early deployment is used to identify installation and operational issues while production capacity is built up and the range of compatible buildings is widened. ## Technology that turns windows and walls into power generation equipment The glass-type perovskite solar cell Panasonic HD is developing is a product in which a thin solar cell film is formed on architectural glass and used as laminated glass. It is a type of building-integrated photovoltaics (BIPV), which builds power generation into windows and exterior walls. Its advantage is that the sides of a building can be used for generation even in urban areas where there is not enough roof space for solar panels. Unlike conventional solar panels, the building material itself generates power, so the technology can be adapted to a building's appearance and purpose. Supporting the larger glass sizes and design flexibility are the company's proprietary materials technology and a manufacturing process that combines inkjet coating with laser processing. This makes it possible to adjust the transparency of the glass and form patterns to suit a building's exterior. The official FAQ, however, also explains that power output changes depending on design requirements. When appearance or daylighting is a priority, it is necessary to check how much those specifications affect generation performance. The way generated electricity is sent to a building's equipment also has to be considered at the design stage. According to the company's FAQ, a junction box for electrical connection is attached to the edge of each glass module, and connections are made through connectors. Wiring is expected to be housed inside the sash or similar framing, so designers must plan not only window dimensions and mounting methods but also the route of the electrical wiring and the connection to the building's electrical system. The technology targets both new construction and renovation of existing buildings. For existing buildings, installation methods such as replacing the glass or adding an inner window will be considered according to each building's conditions. In short, adopting glass-type solar cells requires design and construction as power generation equipment in addition to the usual selection of glass building materials. ## The 18.1% conversion efficiency is a certified value for a small module Panasonic HD has announced that it achieved an energy conversion efficiency of 18.1% with glass-type perovskite solar cells. However, this figure was certified by a third-party organization for a module with an area of 804 cm², and the official FAQ describes it as a measurement result for a module of about 30 cm square. The same conversion efficiency has not been confirmed for the whole of the large glass of up to 1.8 m shown in the mass-production plan. The company continues to develop technology to maintain high conversion efficiency at larger sizes, and the certified value for a small module should be distinguished from the performance of the products actually sold. Furthermore, the amount of power generated once installed in a building varies greatly with the orientation of the glass and sunlight conditions. Glass-type perovskite solar cells can be adjusted for transparency and design, but these specifications also affect generation performance. The 18.1% figure is therefore an indicator of how far technology development has come, but it does not guarantee the annual output obtainable from actual windows or walls. When considering adoption, it will be necessary to estimate power generation based on the installation location and the glass specifications chosen. Evaluations of safety and quality are also under way. The specification chart published by Panasonic HD states "compliant with the Building Standards Act" and notes that the product has passed in-house tests under IEC 61730 for solar module safety and IEC 62790 for junction boxes. A footnote, however, says the company plans to obtain module certification in the future in light of customer requests and industry trends. Passing in-house tests is different from obtaining formal certification from a third-party body, and in actual adoption it will be necessary to check conformity with the standards required for both building materials and solar cells. For long-term durability, too, it is important at this stage to distinguish development goals from proven performance. According to the official FAQ as of October 2026, the company is continuing verification through accelerated degradation tests and other methods, aiming for durability equivalent to ordinary glass building materials as a building material and to crystalline silicon solar cells as a solar cell. This is not a commitment to a specific product lifespan or warranty period. The long-term power generation performance and durability of the product when used as large glass will need to be assessed based on future test results and actual installation conditions. ## Supply volume, pricing and installation costs will be key to adoption Sales of the early-production product began in September 2026, but it is not currently possible to supply every customer who wants it. The official FAQ explains that supply volume of the early-production product is limited and that many inquiries have been received, so it is difficult to respond to new offers. Consultations are being accepted for deliveries from April 2029 onward. Bringing forward the start of mass production is a step toward expanding supply, but how much volume can be stably supplied depends on how production capacity is built up. Pricing is also not fixed at present, with no uniform sales price. According to Panasonic HD, prices vary with glass size, thickness, design, order quantity and other factors. Actual installation costs also depend on the installation site, construction method, the electrical system to be connected and the scope of ancillary work, so quotes must be prepared case by case. Simply comparing the price of a single pane of glass makes it difficult to judge the economics against conventional building materials or solar power equipment. Responses to these installation challenges are already built into the development plan. Under the Green Innovation Fund project of NEDO announced in 2025, mass-production technology development and field demonstrations are planned from fiscal 2025 through fiscal 2029. In this project, Panasonic HD is in charge of stabilizing quality and optimizing the mass-production process, while AGC supports construction aspects, including structural design and quality assurance. In addition, Panasonic Environmental Engineering has put in place a framework to support design and construction from both the architectural and electrical sides. This division of roles shows that putting glass-type perovskite solar cells to practical use requires not only the technology to mass-produce stable-quality products in factories but also installation technology to build them into buildings safely and efficiently. A key question is how far the installation and operating data gained through early-production deployments can be reflected in full-scale production at the Nagahama site. If the power generation performance and long-term durability of large glass, product prices, installation costs and supply conditions become concrete ahead of the April 2029 production start, building designers and owners should be able to assess more accurately the economics of using windows and exterior walls as power generation equipment.