Window-Ratings - Revision history

Simcha: /* Heat Loss and Heat Gain */

2013-03-19T21:28:02Z

Heat Loss and Heat Gain

← Older revision		Revision as of 21:28, 19 March 2013
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	== Heat Loss and Heat Gain ==		== Heat Loss and Heat Gain ==
−	~~The ratings~~ for energy efficient windows concentrate on how the window gains or loses heat. This occurs in any of three different ways:	+	Ratings for energy efficient windows concentrate on how the window gains or loses heat. This occurs in any of three different ways:
−	# Windows gain or lose heat through direct conduction through ~~the window's~~ frame or glazing.	+	# Windows gain or lose heat through direct conduction through its frame or glazing.
	# Windows gain or lose heat through the sun's radiation		# Windows gain or lose heat through the sun's radiation
	# Windows gain or lose heat through air leakage.		# Windows gain or lose heat through air leakage.

−	~~The ratings~~ measure and rate ~~different~~ these different elements.	+	Ratings measure and rate these different elements.

	=== Direct Conduction ===		=== Direct Conduction ===

Simcha: /* Heat Loss and Heat Gain */

2013-03-19T21:25:44Z

Heat Loss and Heat Gain

← Older revision		Revision as of 21:25, 19 March 2013
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	== Heat Loss and Heat Gain ==		== Heat Loss and Heat Gain ==
	The ratings for energy efficient windows concentrate on how the window gains or loses heat. This occurs in any of three different ways:		The ratings for energy efficient windows concentrate on how the window gains or loses heat. This occurs in any of three different ways:
−	1. Windows gain or lose heat through direct conduction through the window's frame or glazing.	+	# Windows gain or lose heat through direct conduction through the window's frame or glazing.
−	2. Windows gain or lose heat through the sun's radiation	+	# Windows gain or lose heat through the sun's radiation
−	3. Windows gain or lose heat through air leakage.	+	# Windows gain or lose heat through air leakage.

	The ratings measure and rate different these different elements.		The ratings measure and rate different these different elements.

Simcha at 21:22, 19 March 2013

2013-03-19T21:22:57Z

← Older revision		Revision as of 21:22, 19 March 2013
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	The [[Energy Star Windows\|Energy Star]] certification provides assurance that a window is able to limit heat transfer and control the amount of solar gain that enters into a home through the window. Energy Star qualified windows lower energy consumption and reduce greenhouse gas emissions through their ability to control weather penetration and heat transfer. Energy Star windows are certified based on the ratings of the National Fenestration Ratings Council but they do not include all the NFRC's component ratings.		The [[Energy Star Windows\|Energy Star]] certification provides assurance that a window is able to limit heat transfer and control the amount of solar gain that enters into a home through the window. Energy Star qualified windows lower energy consumption and reduce greenhouse gas emissions through their ability to control weather penetration and heat transfer. Energy Star windows are certified based on the ratings of the National Fenestration Ratings Council but they do not include all the NFRC's component ratings.

−	Windows which receive the Energy Star label are assessed according to the NFRC's ratings for U-Factor and solar heat gain coefficient but do not take into account the additional ratings -- Air Leakage, Visible Transmittance and Light to Solar Gain. ENERGY STAR® windows are accepted by many governments as windows products that make the buyer eligible for tax credits and rebates	+	Windows which receive the Energy Star label are assessed according to the NFRC's ratings for U-Factor and solar heat gain coefficient but do not take into account the additional ratings -- Air Leakage, Visible Transmittance and Light to Solar Gain. ENERGY STAR® windows are accepted by many governments as windows products that make the buyer eligible for tax credits and rebates.
		+
		+	== Heat Loss and Heat Gain ==
		+	The ratings for energy efficient windows concentrate on how the window gains or loses heat. This occurs in any of three different ways:
		+	1. Windows gain or lose heat through direct conduction through the window's frame or glazing.
		+	2. Windows gain or lose heat through the sun's radiation
		+	3. Windows gain or lose heat through air leakage.
		+
		+	The ratings measure and rate different these different elements.
		+
		+	=== Direct Conduction ===
		+	Conductance refers to the movement of heat through a solid material. As heat conducts through a window's glass panes it transfers heat. Window manufacturers can reduce this conductance by building windows which include multiple panes. Another method for reducing conductance involves adding gas fills which are inserted between the panes. These methods create added thermal barriers between the outside and the inside of a home and help to reduce heat transfer.
		+
		+	Window efficiency ratings assess the effectiveness of these barriers in reducing conductance.
		+
		+	=== Radiative Heat Flow ===
		+	Radiative heat flow encompasses the heat which is caused by the sun's radiation. These solar rays -- also called "solar gain" can cause heat to transfer into a room which then warms the room. Many window manufacturers add a Low Emissivity (Low E) coating to the window's glazing to suppress radiative heat flow and heat transfer as well as to reduce the infrared radiation that is transferred from the warmer pane of glass to the cooler pane. Low E is applied to the window's glass surface and blocks a significant amount of radiant heat transfer, lowering the total heat flow that enters through the window. Low-E coatings are virtually invisible.
		+
		+	Window ratings measure the energy efficiency of coatings that block radiative heat flow and the extent to which they reduce the heat flow, and thus the window's U-Factor.
		+
		+	=== Sunlight Transmittance ===
		+	The transmittance of sunlight is measured and rated according to visible transmittance and light to solar gain.

	== Rating Component ==		== Rating Component ==

Simcha: /* Light-to-Solar Gain */

2013-03-19T21:19:23Z

Light-to-Solar Gain

← Older revision		Revision as of 21:19, 19 March 2013
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	=== Light-to-Solar Gain ===		=== Light-to-Solar Gain ===
−	~~The rating for~~ Light-to-Solar Gain (LSG) ~~indicates~~ the ratio between the visible transmittance and the solar heat gain coefficient. The measurement for light to solar gain assesses the relative efficiency of different types of ~~glazing~~ as daylight ~~is transmitted to gauge how well the glass blocks~~ heat gains. A high LSG rating ~~will indicate~~ that a higher ratio of light is transmitted without ~~significantly~~ adding higher amounts of heat.	+	Light-to-Solar Gain (LSG)is the ratio between the visible transmittance and the solar heat gain coefficient. The measurement for light to solar gain assesses the relative efficiency of different types of glass as they transmit daylight while they block heat gains. A high LSG rating indicates that a higher ratio of light is being transmitted without adding significantly higher amounts of heat.

	=== Visible Transmittance ===		=== Visible Transmittance ===

Simcha: /* Solar Heat Gain Coefficient */

2013-03-19T21:10:29Z

Solar Heat Gain Coefficient

← Older revision		Revision as of 21:10, 19 March 2013
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	=== Solar Heat Gain Coefficient ===		=== Solar Heat Gain Coefficient ===
−	The solar heat gain coefficient (SHGF) relates to a percentage of solar radiation which is either absorbed or directly transmitted through a window, and is subsequently released, creating warmth in the room. When less solar heat is transmitted there is greater shading ability which results in a lower solar heat gain coefficient. Windows with high SHGF ratings transmit more solar heat gain during the winter months while windows with a low SHGF rating reduce cooling loads more effectively during the summer months when they block heat from the sun. ~~The need for a high or low SHGF is dependent on~~ the climate in which ~~the windows are~~ to ~~be installed~~.	+	The solar heat gain coefficient (SHGF) relates to a percentage of solar radiation which is either absorbed or directly transmitted through a window, and is subsequently released, creating warmth in the room. When less solar heat is transmitted there is greater shading ability which results in a lower solar heat gain coefficient. Windows with high SHGF ratings transmit more solar heat gain during the winter months while windows with a low SHGF rating reduce cooling loads more effectively during the summer months when they block heat from the sun. Homeowners will consider the climate in which they live when they decide whether they want to purchase a replacement window with a high or low SHGF.

	=== Air Leakage ===		=== Air Leakage ===

Simcha: /* NFRC Ratings */

2013-03-19T21:07:17Z

NFRC Ratings

← Older revision		Revision as of 21:07, 19 March 2013
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	The National Fenestration Ratings Council (NFRC) is a non-profit, third-party agency which rates, tests, certifies and labels windows according to their ability to provide thermal insulation and protection from the weather. The NFRC provides these ratings in order to assist consumers compare replacement window performance and are used in the Energy Star program.		The National Fenestration Ratings Council (NFRC) is a non-profit, third-party agency which rates, tests, certifies and labels windows according to their ability to provide thermal insulation and protection from the weather. The NFRC provides these ratings in order to assist consumers compare replacement window performance and are used in the Energy Star program.

−	The NFRC rates a window's U-Factor, its solar heat gain coefficient, its visible transmittance, its air leakage and its light to solar gain.	+	The NFRC rates a window's U-Factor, its solar heat gain coefficient, its visible transmittance, its air leakage and its light to solar gain but ENERGY STAR windows® are based only on a window's U-Factor and SHGF ratings.
−	but ENERGY STAR windows® are based on a window's U-Factor and SHGF ratings	+

	=== Energy Star Ratings ===		=== Energy Star Ratings ===

Simcha at 20:59, 19 March 2013

2013-03-19T20:59:19Z

← Older revision		Revision as of 20:59, 19 March 2013
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	=== U-Factor ===		=== U-Factor ===
−	The U-Factor measurement assesses the rate at which a window is able to conduct non-solar heat. This rating~~, also called the U-Factor,~~ represents an entire window's performance including the window's glazing, frame and spacer material. The lower the U-Factor rating, the more energy efficiency the window provides.	+	The U-Factor measurement assesses the rate at which a window is able to conduct non-solar heat. This rating represents an entire window's performance including the window's glazing, frame and spacer material. The lower the U-Factor rating, the more energy efficiency the window provides.

	=== Center of Glass U-Factor ===		=== Center of Glass U-Factor ===
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	=== Air Leakage ===		=== Air Leakage ===
−	~~The~~ rate ~~that~~ air infiltrates into a room from the area ~~that surrounds~~ a window ~~is the window's Air Leakage rating~~. Window spacers, sealants and other weatherstripping products impact on a window's air leakage. A low air leakage rating indicates that the window has a low percentage of air leakage.	+	Air Leakage ratings rate how air infiltrates into a room from the area surrounding a window . Window spacers, sealants and other weatherstripping products impact on a window's air leakage. A low air leakage rating is better and indicates that the window has a low percentage of air leakage.

	=== Light-to-Solar Gain ===		=== Light-to-Solar Gain ===

Simcha at 20:52, 19 March 2013

2013-03-19T20:52:42Z

← Older revision		Revision as of 20:52, 19 March 2013
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	Windows which receive the Energy Star label are assessed according to the NFRC's ratings for U-Factor and solar heat gain coefficient but do not take into account the additional ratings -- Air Leakage, Visible Transmittance and Light to Solar Gain. ENERGY STAR® windows are accepted by many governments as windows products that make the buyer eligible for tax credits and rebates		Windows which receive the Energy Star label are assessed according to the NFRC's ratings for U-Factor and solar heat gain coefficient but do not take into account the additional ratings -- Air Leakage, Visible Transmittance and Light to Solar Gain. ENERGY STAR® windows are accepted by many governments as windows products that make the buyer eligible for tax credits and rebates

−	== Component ~~Ratings~~ ==	+	== Rating Component ==
−		+	Replacement window ratings measure the window's energy efficiency according to energy performance characteristics. These characteristics include U-Factor, the Solar Heat Gain Coefficient, Air Leakage, Visible Transmittance and Light to Solar Gain.
−	Replacement window ratings measure the window's energy efficiency according to energy performance characteristics. These characteristics include ~~the~~ U-Factor, the Solar Heat Gain Coefficient, Air Leakage, Light to Solar Gain ~~and Visible Transmittance~~.	+

	=== U-Factor ===		=== U-Factor ===

Simcha at 20:50, 19 March 2013

2013-03-19T20:50:38Z

← Older revision		Revision as of 20:50, 19 March 2013
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	The NFRC rates a window's U-Factor, its solar heat gain coefficient, its visible transmittance, its air leakage and its light to solar gain.		The NFRC rates a window's U-Factor, its solar heat gain coefficient, its visible transmittance, its air leakage and its light to solar gain.
−		+	but ENERGY STAR windows® are based on a window's U-Factor and SHGF ratings
−		+
−	~~. The label is a reliable tool for determining a window's energy properties and comparing window products.~~	+
−	~~ENERGY STAR® qualified windows carry the NFRC label. ENERGY STAR® windows are accepted by many governments as windows products that make the buyer eligible for tax credits and rebates~~ but ENERGY STAR windows® are based on a window's U-Factor and SHGF ratings ~~and do not take into account the NFRC's additional ratings -- Air Leakage, Visible Transmittance and Light to Solar Gain.~~	+

	=== Energy Star Ratings ===		=== Energy Star Ratings ===
	The [[Energy Star Windows\|Energy Star]] certification provides assurance that a window is able to limit heat transfer and control the amount of solar gain that enters into a home through the window. Energy Star qualified windows lower energy consumption and reduce greenhouse gas emissions through their ability to control weather penetration and heat transfer. Energy Star windows are certified based on the ratings of the National Fenestration Ratings Council but they do not include all the NFRC's component ratings.		The [[Energy Star Windows\|Energy Star]] certification provides assurance that a window is able to limit heat transfer and control the amount of solar gain that enters into a home through the window. Energy Star qualified windows lower energy consumption and reduce greenhouse gas emissions through their ability to control weather penetration and heat transfer. Energy Star windows are certified based on the ratings of the National Fenestration Ratings Council but they do not include all the NFRC's component ratings.

−	Windows which receive the Energy Star label are assessed according to the NFRC's ratings for U-Factor and solar heat gain coefficient.	+	Windows which receive the Energy Star label are assessed according to the NFRC's ratings for U-Factor and solar heat gain coefficient but do not take into account the additional ratings -- Air Leakage, Visible Transmittance and Light to Solar Gain. ENERGY STAR® windows are accepted by many governments as windows products that make the buyer eligible for tax credits and rebates

	== Component Ratings ==		== Component Ratings ==

Simcha at 20:46, 19 March 2013

2013-03-19T20:46:57Z

← Older revision		Revision as of 20:46, 19 March 2013
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	=== NFRC Ratings ===		=== NFRC Ratings ===
−	The National Fenestration Ratings Council (NFRC) is a non-profit, third-party agency which rates and labels windows according to their ability to provide thermal insulation and protection from the weather. The NFRC provides these ratings in order to assist consumers compare replacement window performance and ~~identify~~ Energy Star ~~and NFRC-certified windows~~.	+	The National Fenestration Ratings Council (NFRC) is a non-profit, third-party agency which rates, tests, certifies and labels windows according to their ability to provide thermal insulation and protection from the weather. The NFRC provides these ratings in order to assist consumers compare replacement window performance and are used in the Energy Star program.

	The NFRC rates a window's U-Factor, its solar heat gain coefficient, its visible transmittance, its air leakage and its light to solar gain.		The NFRC rates a window's U-Factor, its solar heat gain coefficient, its visible transmittance, its air leakage and its light to solar gain.
		+
		+
		+	. The label is a reliable tool for determining a window's energy properties and comparing window products.
		+	ENERGY STAR® qualified windows carry the NFRC label. ENERGY STAR® windows are accepted by many governments as windows products that make the buyer eligible for tax credits and rebates but ENERGY STAR windows® are based on a window's U-Factor and SHGF ratings and do not take into account the NFRC's additional ratings -- Air Leakage, Visible Transmittance and Light to Solar Gain.

	=== Energy Star Ratings ===		=== Energy Star Ratings ===