A: Yeah, this is for enthalpy which to your point is linear on the psychometric chart, so that is a great point. And I think the answer to your question is yes, what's happening here just for context for everyone is this is a mixing calculation being done with an air handler, so we have two streams there being mixed. Looks like it's outside air and I want to say some recirculated air being mixed together and then we're calculating the enthalpy of the mixed air.

A: Good psychometric question and you see how the topics build on each other because now you're insisting components and there's this really deep. Psychometrics concept that's coming out. So the answer is the enthalpy is a linear variable on the psychometric chart.