Can I input u-value and g-value of a window without going through the build up process?
Thanks
u-value for windows
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Complex Potential
- VE Expert
- Posts: 467
- Joined: Wed Jan 09, 2013 11:57 am
- Location: Bristol, UK
Re: u-value for windows
U values and g values are derived parameters which means they can be arrived at in several different ways. So, if you are talking about dynamic simulations, the answer would be no.
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RossThompson87
- VE Professor
- Posts: 202
- Joined: Mon Feb 13, 2012 8:56 am
Re: u-value for windows
Yer, unfortunately there isn't really a quick way to do this.
I found it very frustrating so I built a spreadsheet that returns a value of the cavity resistance that would make the default window type give a certain U-value.
The equations for calculating the U-value are simple.
I tried to extend the tool to work with G-values but I couldn't establish the equations IES was using to calculate them - even after going through the relevant standard.
With opaque constructions there is a tool called 'create target construction..' and that may save you some time. The trouble is it asks for a cM value and nobody tends to work with this unit.
Ross
I found it very frustrating so I built a spreadsheet that returns a value of the cavity resistance that would make the default window type give a certain U-value.
The equations for calculating the U-value are simple.
I tried to extend the tool to work with G-values but I couldn't establish the equations IES was using to calculate them - even after going through the relevant standard.
With opaque constructions there is a tool called 'create target construction..' and that may save you some time. The trouble is it asks for a cM value and nobody tends to work with this unit.
Ross