Man facing the camera holding up a small panel, with people standing behind him, in an outdoors setting.

Lead Performer: National Renewable Energy Laboratory – Golden, CO
Partner: Viracon – Owatonna, MN
DOE Total Funding: $2,250,000
FY18 DOE Funding: $750,000
Cost Share: $75,000
Project Term: October 1, 2018 – September 30, 2021
Funding Type: Lab Award

Project Objective

The vision of grid-interactive efficient buildings (GEBs) represents a future where buildings are no longer simply energy sinks; they play an active role in a modern electric grid by dynamically changing energy use and demand patterns in response to signals from the grid. Architectural and occupant demand for glass building facades makes achieving GEBs an extraordinary challenge due to poor thermal performance and limited area for on-site electricity generation.

National Renewable Energy Laboratory’s (NREL) SwitchGlaze is the world’s first switchable photovoltaic window. It tints and transforms into an efficient solar cell when the sun is shining and back into a window with high visible light transmittance when it is not, promising to revolutionize the ability of buildings to generate electricity. In this project, NREL will partner with Viracon, the leading U.S. manufacturer of commercial glazing, to produce a prototype of SwitchGlaze integrated into highly insulating glass units to demonstrate a durable window platform that is highly insulating, switchable, and energy-generating. Work leading up to prototype will center around improving durability and optimizing performance parameters by employing physics-based building energy modeling. SwitchGlaze will be an enabling technology in the transformation of buildings from static energy sinks to dynamic, energy-efficient grid elements that produce electricity.

Project Impact

The greatest barrier to deployment of SwitchGlaze is unproven durability, where performance must persist for 30 years or more. This work will improve SwitchGlaze durability and integrate it into existing high-performance insulating glass units. The proposed work will facilitate industrial partners to commercialize SwitchGlaze technology. Combining high thermal performance, switchability, and energy generation into a single durable window platform will result in a product with a short payback period and unprecedented, grid-flexible performance.


DOE Technology Manager: Marc LaFrance
Lead Performer: Lance Wheeler, National Renewable Energy Laboratory

Related Publications

Wheeler, L. M. et al. Switchable photovoltaic windows enabled by reversible photothermal complex dissociation from methylammonium lead iodide. Nature Communications 8, 1–9 (2017).

Wheeler, L. M. & Wheeler, V. M. Detailed Balance Analysis of Photovoltaic Windows. ACS Energy Lett. 4, 2130–2136 (2019).