You know what guys, I was asked a question about this today just as I was going home and didn't know how to answer.

I've always used deg F when calculating s/heat, as that's just the way I was taught.
I was asked why we don't use dec C in the UK,, as it's generally C that we use for most temp measurements here.

So, lets say we are working in F and looking for a target s/heat on a system of 7f (evaporator), would we still be looking for 7 if converting the pressure / temps to C. In other words, it's just the numerical value we require?

I feel daft asking, but it's never crossed my mind before really.