HVAC Calc

link provided...

Here is a link that might be useful: HVAC Calc

I tried the test one and i must say it was awful--difficult to use and when I made a mistake it halted the process.
There must be better stuff out there.
Their support was equally bad.

HVAC Calc support is bad? I didn't think there was any - I certainly couldn't get any help. Their window section is awful - no SHGC input? Just "low-e" and "reflective coating". While the info I got from using it was helpful - it wasn't worth the money.

You can just use excel and the ASHRAE fundamentals volume.