HVAC design course

Hi guys
I am an install/service engineer who has come off tools to do some project management work. My boss has offered me a chance to get involved in some HVAC/AC design (ducting etc) work which I would love to do but don't have much exp in this.
I have seen distance learning course Btec 3 Heating & Ventilation and was just wondering if anyone else has experience of this course as it seems to offer basics of what I would need. I hold nvq 2 and FGAS 10yrs+ exp and can spec and design AC but it's the vent I really need.
Any done any decent Cad courses also?????

Cheers in advance