SOLAR SERDAR – ENERGY PERFORMANCE RATINGS FOR WINDOWS,DOORS, AND SKYLIGHTS

SOLAR SERDAR -Energy Performance Ratings for Windows, Doors, and Skylights
You can use the energy performance ratings of windows, doors, and skylights to tell you their potential for gaining and losing heat, as well as transmitting sunlight into your home.

Heat Gain and Loss
Windows, doors, skylights can gain and lose heat in the following ways:

Direct conduction through the glass or glazing, frame, and/or door
The radiation of heat into a house (typically from the sun) and out of a house from room-temperature objects, such as people, furniture, and interior walls
Air leakage through and around them.
These properties can be measured and rated according to the following energy performance characteristics:

U-factor
The rate at which a window, door, or skylight conducts non-solar heat flow. It’s usually expressed in units of Btu/hr-ft2-ºF. For windows, skylights, and glass doors, a U-factor may refer to just the glass or glazing alone. But National Fenestration Rating Council U-factor ratings represent the entire window performance, including frame and spacer material. The lower the U-factor, the more energy-efficient the window, door, or skylight.

Solar heat gain coefficient (SHGC)
A fraction of solar radiation admitted through a window, door, or skylight—either transmitted directly and/or absorbed, and subsequently released as heat inside a home. The lower the SHGC, the less solar heat it transmits and the greater its shading ability. A product with a high SHGC rating is more effective at collecting solar heat gain during the winter. A product with a low SHGC rating is more effective at reducing cooling loads during the summer by blocking heat gained from the sun. Therefore, what SHGC you need for a window, door, or skylight should be determined by such factors as your climate, orientation, and external shading. For more information about SHGC and windows, see passive solar window design.

Air leakage
The rate of air infiltration around a window, door, or skylight in the presence of a specific pressure difference across it. It’s expressed in units of cubic feet per minute per square foot of frame area (cfm/ft2). A product with a low air leakage rating is tighter than one with a high air leakage rating.

Sunlight Transmittance
A window’s, door’s, or skylight’s ability to transmit sunlight into a home can be measured and rated according to the following energy performance characteristics:

Visible transmittance (VT)
A fraction of the visible spectrum of sunlight (380 to 720 nanometers), weighted by the sensitivity of the human eye, that is transmitted through a window’s, door’s, or skylight’s glazing. A product with a higher VT transmits more visible light. VT is expressed as a number between 0 and 1. The VT you need for a window, door, or skylight should be determined by your home’s daylighting requirements and/or whether you need to reduce interior glare in a space.

Light-to-solar gain (LSG)
The ratio between the SHGC and VT. It provides a gauge of the relative efficiency of different glass or glazing types in transmitting daylight while blocking heat gains. The higher the number, the more light transmitted without adding excessive amounts of heat. This energy performance rating isn’t always provided.

Energy Performance Testing, Certification and Labeling
The National Fenestration Rating Council (NFRC) operates a voluntary program that tests, certifies, and labels windows, doors, and skylights based on their energy performance ratings. The NFRC label provides a reliable way to determine a window’s energy properties and to compare products.

The NFRC label can be found on all ENERGY STAR® qualified window, door, and skylight products, but ENERGY STAR bases its qualification only on U-factor and SHGC ratings.

See Learn More on the right side of this page (or below if you’ve printed it out) for links to NFRC and ENERGY STAR information.
SOLAR SERDAR
solarserdar@gmail.com

Advertisements

About CROATIAN CENTER of RENEWABLE ENERGY SOURCES

CROATIAN CENTER of RENEWABLE ENERGY SOURCES (CCRES)• was founded in 1988 as the non-profit European Association for Renewable Energy that conducts its work independently of political parties, institutions, commercial enterprises and interest groups, • is dedicated to the cause of completely substituting for nuclear and fossil energy through renewable energy, • regards solar energy supply as essential to preserve the natural resources and a prerequisite for a sustainable economy,• acts to change conventional political priorities and common infrastructures in favor of renewable energy, from the local to the international level, • brings together expertise from the fields of politics, economy, science, and culture to promote the entry of solar energy, • provides the opportunity to play a part in the sociocultural movement for renewable energy by joining the association for everyone, • considers full renewable energy supply a momentous and visionary goal - the challenge of the century to humanity. CCRES Željko Serdar Head of association solarserdar@gmail.com
This entry was posted in ALTERNATIVE and tagged , , , , . Bookmark the permalink.

One Response to SOLAR SERDAR – ENERGY PERFORMANCE RATINGS FOR WINDOWS,DOORS, AND SKYLIGHTS

  1. solarserdar says:

    SOLAR SERDAR
    • was founded in 1988 as the non-profit European Association for Renewable Energy that conducts its work independently of political parties, institutions, commercial enterprises and interest groups,

    • is dedicated to the cause of completely substituting for nuclear and fossil energy through renewable energy,

    • regards solar energy supply as essential to preserve the natural resources and a prerequisite for a sustainable economy,

    • acts to change conventional political priorities and common infrastructures in favor of renewable energy, from the local to the international level,

    • brings together expertise from the fields of politics, economy, science, and culture to promote the entry of solar energy,

    • provides the opportunity to play a part in the sociocultural movement for renewable energy by joining the association for everyone,

    • considers full renewable energy supply a momentous and visionary goal – the challenge of the century to humanity.

    SOLAR SERDAR

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s