R-value - Revision history

Jmdonev: /* Calculating R-value */

2023-11-07T19:12:21Z

Calculating R-value

← Older revision		Revision as of 19:12, 7 November 2023
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	*<math> \Delta T </math> is the temperature difference inside and outside the house in °F (or °C for RSI)		*<math> \Delta T </math> is the temperature difference inside and outside the house in °F (or °C for RSI)
	*<math> Area </math> is the area of the wall (or ceiling) that's being insulated in ft <sup>2</sup> (or m<sup>2</sup> for RSI)		*<math> Area </math> is the area of the wall (or ceiling) that's being insulated in ft <sup>2</sup> (or m<sup>2</sup> for RSI)
	*<math> Time </math> is how long the measurement took place in seconds ~~(same in~~ RSI)		*<math> Time </math> is how long the measurement took place in hours (seconds for RSI)
	*<math> Heat Loss</math> is how much heat is lost through the wall in [[BTU]] ([[joule\|J]] in RSI)		*<math> Heat Loss</math> is how much heat is lost through the wall in [[BTU]] ([[joule\|J]] in RSI)

	To convert from an RSI value to an R-value multiply by 6. If one insulation material is put on top of another insulation material, the R-values just add. For a helpful online R-value calculator from Ekotrope, click [http://www.ekotrope.com/products/r-value-calculator/ here].		To convert from an RSI value to an R-value multiply by 6. If one insulation material is put on top of another insulation material, the R-values just add. For a helpful online R-value calculator from Ekotrope, click [http://www.ekotrope.com/products/r-value-calculator/ here].


	==References==		==References==
	{{reflist}}		{{reflist}}
	[[Category:Uploaded]]		[[Category:Uploaded]]

Jmdonev: 1 revision imported

2021-09-27T00:03:13Z

1 revision imported

← Older revision	Revision as of 00:03, 27 September 2021
(No difference)

energy>Ethan.boechler at 21:22, 10 September 2021

2021-09-10T21:22:23Z

← Older revision		Revision as of 21:22, 10 September 2021
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	[[Category:~~Done 2018-05-18~~]]		[[Category:Zach edit]]
			[[Category:Translated to French]]
			[[fr:Valeur R]]
	[[File:320px-Polyisocyanurate_insulation_boards.jpg\|400px\|framed\|right\|Figure 1. Polyisocyanurate insulation, this type of insulation is similar to polyurethane but has a higher R-value.<ref>"Polyisocyanurate insulation boards" Polyisocyanurate Insulation BoardUploaded by Leyo. Licensed under CC BY-SA 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Polyisocyanurate_insulation_boards.jpg#/media/File:Polyisocyanurate_insulation_boards.jpg</ref>]]		[[File:320px-Polyisocyanurate_insulation_boards.jpg\|400px\|framed\|right\|Figure 1. Polyisocyanurate insulation, this type of insulation is similar to polyurethane but has a higher R-value.<ref>"Polyisocyanurate insulation boards" Polyisocyanurate Insulation BoardUploaded by Leyo. Licensed under CC BY-SA 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Polyisocyanurate_insulation_boards.jpg#/media/File:Polyisocyanurate_insulation_boards.jpg</ref>]]

Jmdonev at 20:25, 10 June 2020

2020-06-10T20:25:13Z

← Older revision		Revision as of 20:25, 10 June 2020
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	* Expanded Polystyrene: 4.00/inch		* Expanded Polystyrene: 4.00/inch

	R-values, as shown above, are expressed in [[imperial system of units\|imperial units]], specifically °F ft<sup>2</sup> ~~sec~~/[[BTU]]. R-values do however have a [[metric system of units\|metric]] equivalent, known as the RSI value (which are °C m<sup>2</sup> sec/[[joule\|J]]). Insulating products sold in Canada are labelled with both R and RSI values for clarity.<ref name='CMHC'> Canada Mortgage and Housing Corporation. (March 14, 2015). ''Insulating Your House'' [Online]. Available: http://www.cmhc-schl.gc.ca/en/co/grho/grho_010.cfm</ref>		R-values, as shown above, are expressed in [[imperial system of units\|imperial units]], specifically °F ft<sup>2</sup> hr/[[BTU]]. R-values do however have a [[metric system of units\|metric]] equivalent, known as the RSI value (which are °C m<sup>2</sup> sec/[[joule\|J]]). Insulating products sold in Canada are labelled with both R and RSI values for clarity.<ref name='CMHC'> Canada Mortgage and Housing Corporation. (March 14, 2015). ''Insulating Your House'' [Online]. Available: http://www.cmhc-schl.gc.ca/en/co/grho/grho_010.cfm</ref>

	In Canada, provincial building codes specify minimum R/RSI values for new construction.<ref name='CMHC'/> The recommended R-value for basement insulation in North America is R12,<ref name='SS'/> but the R-value in insulation is lowered substantially when there is air or moisture leaks. Thus the standard R-value varies by climate, temperature, and specific conditions.		In Canada, provincial building codes specify minimum R/RSI values for new construction.<ref name='CMHC'/> The recommended R-value for basement insulation in North America is R12,<ref name='SS'/> but the R-value in insulation is lowered substantially when there is air or moisture leaks. Thus the standard R-value varies by climate, temperature, and specific conditions.

Jmdonev: 1 revision imported

2018-05-18T22:53:12Z

1 revision imported

← Older revision	Revision as of 22:53, 18 May 2018
(No difference)

Jmdonev at 22:37, 11 May 2018

2018-05-11T22:37:01Z

← Older revision		Revision as of 22:37, 11 May 2018
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	[[Category:Done ~~2015~~-06-01]]		[[Category:Done 2018-05-18]]
	[[File:320px-Polyisocyanurate_insulation_boards.jpg\|400px\|framed\|right\|Figure 1. Polyisocyanurate insulation, this type of insulation is similar to polyurethane but has a higher R-value.<ref>"Polyisocyanurate insulation boards" Polyisocyanurate Insulation BoardUploaded by Leyo. Licensed under CC BY-SA 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Polyisocyanurate_insulation_boards.jpg#/media/File:Polyisocyanurate_insulation_boards.jpg</ref>]]		[[File:320px-Polyisocyanurate_insulation_boards.jpg\|400px\|framed\|right\|Figure 1. Polyisocyanurate insulation, this type of insulation is similar to polyurethane but has a higher R-value.<ref>"Polyisocyanurate insulation boards" Polyisocyanurate Insulation BoardUploaded by Leyo. Licensed under CC BY-SA 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Polyisocyanurate_insulation_boards.jpg#/media/File:Polyisocyanurate_insulation_boards.jpg</ref>]]

	<onlyinclude>The '''R-value''' of [[insulation]] is a value that is used to measure how well a specific type of insulation can resist [[heat transfer\|heat flow]]. The higher the R-value, the more effective the material is at preventing heat transfer.</onlyinclude><ref name='SS'>Superseal Construction Products Ltd. (March 14, 2014). ''R-Value'' [Online]. Available: http://rvalue.net</ref> R-value is short for '''Resistance value''', and ~~is which~~ is closely related to the metric unit of RSI. [[Window]]s also have a specific R-value associated with how well they keep heat in (although the heat that comes from sunlight coming through the window is not included in R-values, it's an important part of the net effect of having a window in a particular wall). R-value is also related to [[U-value]] (which is 1/R-value) and [[thermal conductivity]] which is a property of a material that says how well it conducts [[heat]].		<onlyinclude>The '''R-value''' of [[insulation]] is a value that is used to measure how well a specific type of insulation can resist [[heat transfer\|heat flow]]. The higher the R-value, the more effective the material is at preventing heat transfer.</onlyinclude><ref name='SS'>Superseal Construction Products Ltd. (March 14, 2014). ''R-Value'' [Online]. Available: http://rvalue.net</ref> R-value is short for '''Resistance value''', and is closely related to the metric unit of RSI. [[Window]]s also have a specific R-value associated with how well they keep heat in (although the heat that comes from sunlight coming through the window is not included in R-values, it's an important part of the net effect of having a window in a particular wall). R-value is also related to [[U-value]] (which is 1/R-value) and [[thermal conductivity]] which is a property of a material that says how well it conducts [[heat]].

	Different insulating materials each have their own unique R-value per unit length. The thicker the material the more it resists heat transfer so values are listed per inch (and then multiplying the value by the thickness of the insulation gives the R-value). Some of the best insulation materials for buildings are:<ref name='SS'/>		Different insulating materials each have their own unique R-value per unit length. The thicker the material the more it resists heat transfer so values are listed per inch (and then multiplying the value by the thickness of the insulation gives the R-value). Some of the best insulation materials for buildings are:<ref name='SS'/>
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	Mathematically, R-value is calculating from a measuring heat flow across a surface where each side is at a particular temperature:<ref name='CIMA'>CIMA. (March 14, 2015). ''What R-Value Means'' [Online]. Available: http://www.cellulose.org/HomeOwners/WhatR-valueMean.php</ref>		Mathematically, R-value is calculating from a measuring heat flow across a surface where each side is at a particular temperature:<ref name='CIMA'>CIMA. (March 14, 2015). ''What R-Value Means'' [Online]. Available: http://www.cellulose.org/HomeOwners/WhatR-valueMean.php</ref>

	<center><m> R-Value = \frac{\Delta T \times Area \times Time}{Heat Loss} </m></center>		<center><math> R-Value = \frac{\Delta T \times Area \times Time}{Heat Loss} </math></center>

	*<m> \Delta T </m> is the temperature difference inside and outside the house in °F (or °C for RSI)		*<math> \Delta T </math> is the temperature difference inside and outside the house in °F (or °C for RSI)
	*<m> Area </m> is the area of the wall (or ceiling) that's being insulated in ft <sup>2</sup> (or m<sup>2</sup> for RSI)		*<math> Area </math> is the area of the wall (or ceiling) that's being insulated in ft <sup>2</sup> (or m<sup>2</sup> for RSI)
	*<m> Time </m> is how long the measurement took place in seconds (same in RSI)		*<math> Time </math> is how long the measurement took place in seconds (same in RSI)
	*<m> Heat Loss</m> is how much heat is lost through the wall in [[BTU]] ([[joule\|J]] in RSI)		*<math> Heat Loss</math> is how much heat is lost through the wall in [[BTU]] ([[joule\|J]] in RSI)

	To convert from an RSI value to an R-value multiply by 6. If one insulation material is put on top of another insulation material, the R-values just add. For a helpful online R-value calculator from Ekotrope, click [http://www.ekotrope.com/products/r-value-calculator/ here].		To convert from an RSI value to an R-value multiply by 6. If one insulation material is put on top of another insulation material, the R-values just add. For a helpful online R-value calculator from Ekotrope, click [http://www.ekotrope.com/products/r-value-calculator/ here].

J.williams: 1 revision imported

2015-08-26T21:31:34Z

1 revision imported

← Older revision	Revision as of 21:31, 26 August 2015
(No difference)

J.williams at 16:58, 12 August 2015

2015-08-12T16:58:45Z

New page

[[Category:Done 2015-06-01]]
[[File:320px-Polyisocyanurate_insulation_boards.jpg|400px|framed|right|Figure 1. Polyisocyanurate insulation, this type of insulation is similar to polyurethane but has a higher R-value.<ref>"Polyisocyanurate insulation boards" Polyisocyanurate Insulation BoardUploaded by Leyo. Licensed under CC BY-SA 2.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Polyisocyanurate_insulation_boards.jpg#/media/File:Polyisocyanurate_insulation_boards.jpg</ref>]]

<onlyinclude>The '''R-value''' of [[insulation]] is a value that is used to measure how well a specific type of insulation can resist [[heat transfer|heat flow]]. The higher the R-value, the more effective the material is at preventing heat transfer.</onlyinclude><ref name='SS'>Superseal Construction Products Ltd. (March 14, 2014). ''R-Value'' [Online]. Available: http://rvalue.net</ref> R-value is short for '''Resistance value''', and is which is closely related to the metric unit of RSI. [[Window]]s also have a specific R-value associated with how well they keep heat in (although the heat that comes from sunlight coming through the window is not included in R-values, it's an important part of the net effect of having a window in a particular wall). R-value is also related to [[U-value]] (which is 1/R-value) and [[thermal conductivity]] which is a property of a material that says how well it conducts [[heat]].

Different insulating materials each have their own unique R-value per unit length. The thicker the material the more it resists heat transfer so values are listed per inch (and then multiplying the value by the thickness of the insulation gives the R-value). Some of the best insulation materials for buildings are:<ref name='SS'/>

* Blown in Cellulose Insulation: 3.70/inch
* Fiberglass Insulation: 3.14/inch
* Expanded Polystyrene: 4.00/inch

R-values, as shown above, are expressed in [[imperial system of units|imperial units]], specifically °F ft2 sec/[[BTU]]. R-values do however have a [[metric system of units|metric]] equivalent, known as the RSI value (which are °C m2 sec/[[joule|J]]). Insulating products sold in Canada are labelled with both R and RSI values for clarity.<ref name='CMHC'> Canada Mortgage and Housing Corporation. (March 14, 2015). ''Insulating Your House'' [Online]. Available: http://www.cmhc-schl.gc.ca/en/co/grho/grho_010.cfm</ref>

In Canada, provincial building codes specify minimum R/RSI values for new construction.<ref name='CMHC'/> The recommended R-value for basement insulation in North America is R12,<ref name='SS'/> but the R-value in insulation is lowered substantially when there is air or moisture leaks. Thus the standard R-value varies by climate, temperature, and specific conditions.

Although effective, looking at R-value alone isn't enough to determine how well an insulation will work. Since heat moves by [[conduction]], [[convection]], [[radiation]], and air infiltration, all of these must be accounted for to truly know how well any one insulation will work. R-value measures only conduction, and thus doesn't provide the whole picture.<ref name='CIMA'/> As well, R-value doesn't take into account individual factors such as wind, humidity, and [[temperature]] changes which can cause air flow and leakages in the insulation of the [[building envelope|building]].<ref name='CIMA'/> These factors change how well a specific type of insulation works, effectively changing it's R-Value, but this is very hard to measure.<ref>How-To Home Insulation. (March 14, 2015). ''R-Value'' [Online]. Available: http://howtohomeinsulation.com/insulation_basics_rvalue.html</ref>
 
 

==Calculating R-value==

Mathematically, R-value is calculating from a measuring heat flow across a surface where each side is at a particular temperature:<ref name='CIMA'>CIMA. (March 14, 2015). ''What R-Value Means'' [Online]. Available: http://www.cellulose.org/HomeOwners/WhatR-valueMean.php</ref>

<center><m> R-Value = \frac{\Delta T \times Area \times Time}{Heat Loss} </m></center>

*<m> \Delta T </m> is the temperature difference inside and outside the house in °F (or °C for RSI)
*<m> Area </m> is the area of the wall (or ceiling) that's being insulated in ft 2 (or m2 for RSI)
*<m> Time </m> is how long the measurement took place in seconds (same in RSI)
*<m> Heat Loss</m> is how much heat is lost through the wall in [[BTU]] ([[joule|J]] in RSI)

To convert from an RSI value to an R-value multiply by 6. If one insulation material is put on top of another insulation material, the R-values just add. For a helpful online R-value calculator from Ekotrope, click [http://www.ekotrope.com/products/r-value-calculator/ here].

==References==
{{reflist}}
[[Category:Uploaded]]