IES-VE User Forum

Can I input u-value and g-value of a window without going through the build up process?

Thanks

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.

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