Low-emissivity colored paints with conductive polymers for year-round energy-efficient buildings
Colorful low-e paints (ε≈0.19) that reduce HVAC loads year-round while preserving architectural aesthetics.
Researchers at Purdue University have developed colorful, bilayer paints that reduce radiative heat transfer between building walls and their surroundings. Existing low-emissivity (low-e) paints maintain indoor temperature but have a metallic appearance that has hindered their adoption. The Purdue low-e paint contributes to thermal stabilization by minimizing heat transfer between the interior of a building and its external environment while maintaining aesthetic appeal. This paint can be made to selectively reflect different wavelengths of visible light, allowing it to appear in a wide range of colors. It can be sprayed or brushed on to a variety of surfaces, making it incredibly versatile and useful in many different scenarios, including building envelopes and cold chain transportation. With its low-e properties, this innovative paint contributes to more energy-efficient building practices, particularly in high-density urban areas.
Technology Validation:
A very low thermal emissivity of 0.19 over 5 µm to 20 µm wavelength range was achieved, much lower than the 0.95 emissivity of commercial paints. It is predicted that, in the case of a typical midrise apartment building in Seattle, the HVAC system could save up to 30 GJ annually, representing potential cost savings of thousands of dollars per year.
Advantages:
-Low emissivity
-Reduces heat transfer, improving energy efficiency
-Wide range of color options
-Multiple application options
-Appropriate for multiple surface types
-May reduce energy demands in dense urban areas
Applications:
-Paint applications where low heat transfer is desired, such as:
-Energy-efficient buildings
-Envelopes
-Cold chain transportation
Publications:
High-Performance Low-Emissivity Paints Enabled by N-Doped Poly(benzodifurandione) (n-PBDF) for Energy-Efficient Buildings. Advanced Functional Materials. https://doi.org/10.1002/adfm.202419685
TRL: 3
Intellectual Property:
Provisional-Patent, 2025-04-25, United States
Keywords: Chemical Engineering, Electrical Engineering, Electrochemical Materials, Gas diffusion layers (GDL), PEDOT, PTFE