Item ID: 262
Window Glazing: Electrochromic vs. Conventional
Windows that can modulate heat gain, light transmittance, and glare from the sun and can be controlled locally or by an energy management system.
Windows with electrochromatic tinting capability are currently offered by Sage Electrochromics and Soladigm. Electrochromic windows can be controlled to modulate both heat, light, and glare from the sun while preserving views. These windows can be controlled locally or interconnected into a building automation system.
Electrochromic window glass is fabricated into industry standard units that fit into a variety of window, skylight, and curtain wall frame sizes. These smart windows negate the need for traditional sun control building add-ons such as shades, blinds, or overhangs. Electrochromic windows can be controlled in a number of ways: two tint levels (fully tinted and fully clear); four tint levels (fully tinted, fully clear, and two intermediate levels); configured to maintain a constant light level, or automatic control by the building energy management system based upon time of day or occupancy sensor readings.
The Sage webiste cites a U.S. Department of Energy study that estimates that electronically tintable windows systems are capable of providing up to:
---a 20% savings in operating costs
---a 24% reduction in peak demand, and
---a 25% decrease in the size (capacity) of HVAC systems.
Electrochromic windows are ideal for offices, museums, libraries, art galleries, health care facilities, schools and universities, religious buildings, and high-tech or image buildings. Electrochromic windows are installed at the Health Sciences Complex at Chemketa Community College in Salem, OR.
The technology did not develop a market when available at $100 per square foot. Prices in mid-2013 are as low as $30 per square foot of glass, and are expected to continue dropping at 5-10% annually. Electrochromic windows provide additional benefits in applications where glare and heat gain are periodically big issues. View Inc claims that the savings in HVAC system sizing and elimination of blinds etc. can pay the incremental cost, especially for institutional owner occupants such as healthcare, education and government with long payback horizons.
Energy Savings: 19%
Energy Savings Rating:
Limited Assessment What's this?
|1||Concept not validated||Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.|
|2||Concept validated:||An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.|
|3||Limited assessment||An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline. |
|4||Extensive assessment||Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions. |
|5||Comprehensive analysis||Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.|
|6||Approved measure||Protocols for technology application are established and approved.|