Nanotechnology, in particular nanophotonics, is proving essential to achieving green outcomes of
sustainability and renewable energy at the scales needed. Coatings, composites and polymeric structures used
in windows, roof and wall coatings, energy storage, insulation and other components in energy efficient
buildings will increasingly involve nanostructure, as will solar cells. Nanostructures have the potential to
revolutionize thermoelectric power and may one day provide efficient refrigerant free cooling.
Nanomaterials enable optimization of optical, opto-electrical and thermal responses to this urgent task.
Optical harmonization of material responses to environmental energy flows involves (i) large changes in
spectral response over limited wavelength bands (ii) tailoring to environmental dynamics. The latter includes
engineering angle of incidence dependencies and switchable (or chromogenic) responses. Nanomaterials can
be made at sufficient scale and low enough cost to be both economic and to have a high impact on a short
time scale. Issues to be addressed include human safety and property changes induced during manufacture,
handling and outdoor use. Unexpected bonuses have arisen in this work, for example the savings and
environmental benefits of cool roofs extend beyond the more obvious benefit of reduced heat flows from the
roof into the building.