What is the fully burdened hourly rate for an HVAC installer?
Correct me if I'm wrong, but I think the underlying question you're asking is, "how do I determine a fair price for HVAC work?"

Unfortunately, answering that does not involve forensic accounting, as the four things that go into a price (labor, materials, overhead and profit) are all exceptionally (and surprisingly) variable. I wrote a small diatribe on that subject here: Is is appropriate to negotiate price with contractor

So, the same advice I gave on that other question applies here. Get quotes. Try to compare apples to apples. Find a contractor whose sensibilities match yours. If all the quotes come in too high, ask about what you might cut from the quote to get a better price. (Or maybe there's seasonality that can be used to your advantage.)