No mass material in energy plus

i want to create no mass material for my i do create this?

There is actually a component for that.

oh yes thank you. what amount should i enter the r value?

Look at this:…

The R value is the only one you are supposed to know, so E+ don’t calculate it based on the “standard” definition of constructions. As you can see it is not highly recommended to use for large areas since it doesn’t take into account the influence of the mass.