Research Project Information

Research Project Summary Information

Electrochromic Window Trials in NYS(ST4941-1)

Sage Electrochromics, Inc.


Smart-window technologies have the potential to offer significant energy savings by dynamically coupling a building's envelope with its heating and cooling equipment. Sage Electrochromics, Inc. has developed an innovative ceramic thin-film, lithium-ion system suitable for smart-window applications. Sage's technology has been tested by several third-party laboratories (including the National Renewable Energy Laboratory) to establish its performance and durability characteristics. In 1996, Sage established a working relationship with Four Seasons Sunrooms to explore the viability of using an electrochromic (EC) smart-window technology in commercial skylights and residential sun rooms. Four Seasons, in Holbrook, NY, is the world's largest manufacturer of sun spaces and is a major skylight manufacturer.

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Project Description

Sage planned to conduct market research to determine the potential opportunities for smart windows by building type, window type, and control requirements, as well as perform computer analyses to determine the energy and equipment cost savings attributable to smart windows, as compared to other static window technologies in various commercial building types. Sage also intended to develop and optimize the control system for switching the smart window and construct three small "room-like" test structures with different window technologies in Holbrook, NY. Finally, it aimed to monitor these test structures to measure the technology's ability to control room temperatures and modulate lighting levels, as compared to reflective and spectrally selective glazings, and analyze the feasibility of establishing a full-scale manufacturing facility in New York State.


Sage's smart-window technology could potentially reduce energy requirements by 15%, and peak demand by 10%, in New York State office buildings, as compared to other energy-efficient glazing technologies.

Project Results

Computer simulations were used to calculate anticipated life cycle cost savings and payback periods for EC windows based on energy and other building maintenance/equipment savings versus other building scenarios. One set of scenarios determined that, for a large, new building in New York City that uses shades but no day light dimming controls, the first cost investment in EC glazings/day lighting dimming control system provided simple paybacks in the range of six to eighteen months. Other promising scenarios gave payback periods within five years. This project also completed an outdoor field demonstration of skylights with day light dimming controls with Four Seasons Solar Products, a New York State manufacturer of skylights and atriums. The types of skylights included in the demonstration were EC, clear low-e, and dark low-e. The demonstration found that the lighting energy usage was reduced by approximately 17% for the room with EC skylights when compared to the room with dark low-e skylights and day light dimming controls. The energy consumed by the EC skylights as a result of switching was on the order of 0.25% of the amount consumed for the lighting. Lighting energy for the room installed with the clear low-e skylights and day light dimming controls installed was approximately 7% less than for the EC skylights. This energy usage difference would be expected to be more than made up for in savings from reduced cooling loads. Glare on work plane surfaces was lowest with the EC skylight.


Sage Electrochromics, Inc.
2150 Airport Drive Suite 2
Faribault, MN 55021

Principle Investigator

Neil Sbar

Universities Involved


Project Type:

Product Development

Technologies Types:

Building Systems

NYSERDA Contact Information

Robert Carver


R&D - Buildings Research

Contract Details

Start Date: 1/11/2010
Project Status: Active
Contract Number: ST4941-1

Last Updated: 11/17/2014