# A rated windows



## ralphf (Oct 3, 2011)

*Zero does not seem possible*



amyevans said:


> I've been looking into these recently http://www.stormclad.co.uk/arated.php
> 
> Does anyone know anymore about this type of window?
> 
> Apparently they reduce the energy lost through the windows to zero; is this even possible? And does anyone know how much this might save on heating bills?


 They State zero none but there graph shows A has 1.2 rating. For zero loss I think the rating would have to be 0. Even a vacuum thermos bottle has heat loss. My opinion not possible to have zero heat loss if the outside temperature is lower than inside temperature. Maybe contact them for clarification of the zero none statement


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## amyevans (Feb 25, 2011)

ralphf said:


> They State zero none but there graph shows A has 1.2 rating. For zero loss I think the rating would have to be 0. Even a vacuum thermos bottle has heat loss. My opinion not possible to have zero heat loss if the outside temperature is lower than inside temperature. Maybe contact them for clarification of the zero none statement


Thanks Ralph, that's what I was thinking, except you've actually managed to explain why I was thinking it!

I just might give them a call...


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## AGWhitehouse (Jul 1, 2011)

Well that's false advertisement if I've every seen it. It says an "A" rating is the highest a double pane window can achieve. I can tell you that a double-pane window is not the most efficient window available. When you call them, ask what the U-value is. U-value is the inverse of the R-value (thermal resistance value).

The industry "Energy Star" efficiency windows right now are R-5 (U-0.20). These are triple pane. There are more efficient windows but they can get really pricey and sometimes totally custom.


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## SPS-1 (Oct 21, 2008)

AGWhitehouse said:


> The industry "Energy Star" efficiency windows right now are R-5 (U-0.20).


Now the OP is really going to be confused. His location is England. U value in Europe is measured in Watts......., and in the US they are measured in BTU........ (too many units to list them all). 
So they are different. I read where European U value is 5.678 times bigger than US U value. If this is accurate than a US 0.2 equals a European 1.14 U value. These guys were advertising 1.2. So That would make these rather good windows, but not extraordinary windows.


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## AGWhitehouse (Jul 1, 2011)

SPS-1 said:


> Now the OP is really going to be confused. His location is England. U value in Europe is measured in Watts......., and in the US they are measured in BTU........ (too many units to list them all).
> So they are different. I read where European U value is 5.678 times bigger than US U value. If this is accurate than a US 0.2 equals a European 1.14 U value. These guys were advertising 1.2. So That would make these rather good windows, but not extraordinary windows.


Oooohhh...Thanks! Maybe someday, as technology brings us closer together, we'll have common systems and measurements.


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## operagost (Jan 8, 2010)

AGWhitehouse said:


> Oooohhh...Thanks! Maybe someday, as technology brings us closer together, we'll have common systems and measurements.


I don't think I'll get used to telling people I weigh about 11 1/2 stone.


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## DangerMouse (Jul 17, 2008)

SPS-1 said:


> His location is England. U value in Europe is measured in Watts......., and in the US they are measured in BTU........


Thank you for the laugh.... 

BTU stands for WHAT again? :laughing: 

Yeah, it's confusing all right. Maybe someday we'll all speak the same language too.....?

DM


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