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Photovoltaic glass is laminated glass that also generates electricity. A draft international definition collected by IEA PVPS, ISO/FDIS 18178, puts it in one sentence: laminated solar photovoltaic glass is laminated glass that integrates the function of photovoltaic power generation. The same document’s building definitions separate two uses. Building-integrated photovoltaics replace conventional materials in the roof, the skylight, or the facade. Building-attached photovoltaics are fixed to the building and do not replace those materials. The front sheet of an ordinary framed module is cover glass. It is not, by itself, photovoltaic glass.

That distinction matters when a facade drawing says “PV glass” and the quote is for standard modules on a rail. One product is asked to be a construction product. The other is asked to make kilowatt-hours on a rack. They can use similar cells. They do not pass the same tests, and they do not fail in the same way.

What photovoltaic glass has to do besides generate

EN 50583, as summarized in the IEA PVPS definitions report, treats a module as building-integrated when it is a construction product. If you remove it, the building function has to be replaced by another construction product. The functions listed there include mechanical rigidity, primary weather protection against rain, snow, wind, and hail, energy performance such as shading, daylight, or insulation, fire protection, noise protection, and the separation of indoors from outdoors. Making electricity, on its own, does not qualify. A module that only generates, and leaves the weather to the roof underneath, is attached, not integrated.

IEC 63092-1, in a later IEA categorization report, sorts integrated applications by whether they are in the envelope, whether you can touch them from inside the building, and whether the surface is sloped. Category A is a sloping roof-integrated module you cannot reach from inside. Category E includes external layers such as balustrades, shutters, and louvers that still provide a building function. A balcony rail that is also a module is not the same object as a module clamped above a tile. The rail has to be a rail if the module is gone. The tile roof does not.

Because photovoltaic glass is a building product, it sits under building rules as well as electrical rules. The 2024 IEA PVPS standardization report says standard modules certified only as electricity generators are often applied to buildings as building-applied photovoltaics and are often not suitable as the envelope. The extra work is architectural and regulatory. It is not a coating you add to a datasheet.

What photovoltaic glass is not

It is not a promise of a particular efficiency. Cell-record tables measure small devices at standard test conditions. A laminated pane in a facade is a module, often partly transparent, often not aimed at the annual optimum, and often warmer or more shaded than a rack. Transparency and watts trade off: light you let into the room is light the cell did not absorb. No single transmittance belongs in this article, because no one figure was opened that applies to every pane.

It is not immune to heat, shade, or soiling. A vertical facade sees a different sun path from a tilted rack. Shade from a mullion is local and can pull a series string down. Module-level electronics can recover a portion of a shading loss. NREL’s 2016 update put that recovery, for the products it evaluated, around 25 to 35 percent of the shading loss, and the larger experimental difference was how the strings were paralleled. That is not 35 percent more energy than a clear rack. The shade article is how shade affects PV output.

It is not a reason to skip the disconnect. The cells are live in daylight, including the daylight that comes through a curtain wall. Pacific Northwest National Laboratory’s shutdown order, AC disconnect then DC disconnect, still applies, and only trained people open the wiring. A facade is a worse place to improvise than a ground row.

How to specify photovoltaic glass

Ask whether the pane replaces a building function. If the answer is yes, you are in the integrated column, and the glass has to be specified as a construction product with a fire, weather, and structural role, plus an electrical role. If the answer is no, buy a module and a mount, and do not call the cover photovoltaic glass. The side-by-side of those two procurement paths is in BIPV versus BAPV.

Ask for the electrical nameplate at standard test conditions, the temperature coefficients, the maximum system voltage, and the mechanical load. Xcel Energy’s 2023 module requirements, written for crystalline modules that utility buys, show how long that list is even before the product is also a window: power, efficiency, current and voltage, a positive-only power tolerance, output at other irradiances and temperatures, temperature coefficients, and maximum system voltage. A facade pane needs the building tests on top of that list, not instead of it.

Ask who replaces it. A 25-year power warranty that ships a pane and leaves the curtain-wall crew to you is a glass-and-crane problem, not a pallet problem. Warranties are contracts. They are unpacked in what a solar panel warranty covers. On a facade, access dominates the cost, which is the same lesson PNNL draws for ordinary roofs.

Frequently asked questions

Is the glass on a normal solar panel photovoltaic glass?

No. That sheet protects the cells. Photovoltaic glass, in the ISO wording collected by IEA PVPS, is laminated glass that itself generates electricity. A framed module on a rail is a module. It becomes building-integrated only if removing it means you must replace a building function.

Does photovoltaic glass produce as much as a rooftop module?

Not as a rule. Facade glass is often partly transparent, vertical, and shaded by the building. Compare nameplates and then compare orientation. Do not copy a rack-mount yield onto a curtain wall.

Can any solar module be used as photovoltaic glass?

A standard module is often acceptable as building-applied photovoltaics and often unacceptable as the weather layer. IEA PVPS says that directly. The building code and the glass standard decide, not the wattage sticker.

Sources and references

Laminated photovoltaic glass, and the EN 50583 and ISO wording for integrated versus attached: IEA PVPS, international definitions of BIPV. Application categories in IEC 63092-1: IEA PVPS, categorization of BIPV applications. Why a standard module is often the wrong envelope: IEA PVPS, BIPV standardization, 2024. Datasheet contents under one buyer’s spec: Xcel Energy PV module requirements, 2023. Shading-loss recovery for the module-level products tested: NREL, 2016.