Doggone it, I have a degree in mechanical engineering, plus a master's in engineering science. I doubt if he has any degree, except maybe snobbery. He had no right to be rude to me or any caller.
Ok I can't resist so here is my 2 cents.
First: You don't have a degree in HVAC obviously and need their help.
Second: You are asking very general questions. If I called you with very general questions that normally you consult out for a fee of, would you answer my questions or probably more so, ask how I got your number as you work with co's and not individuals. Isn't the lowly hvac guys time worth something?
Third: You are asking questions to people who do not have the time to handle individual persons. They handle accounts or general questions. Of which, you fall into the middle as you are beyond the general person calling with stupid questions and are under the guy that buys 50 furnaces in a month off of them.
Forth: You are also asking someone to give you advice on how to work around paying them. How would you respond if I asked you how to make something and implement it, but I'm only going to have you do the real tough parts like the cad and machining the main guts then I'm going to have someone else do the assembly and implementation BUT you have to tell me how to do it and be there when it goes cockeyed to blame.
Fifth: You are going to get some 'real world' words from people in the HVAC industry. They from what I can tell so far, do not mince words and have LONG ago cut the politically correct speak and niceness in the attitude. It's business and if you annoy them, they will let you know it. Most likely, it's THEIR business too and business is good.
Sixth: You are not doing well for those of us that respect the tradesman out there that are in the science field. I listen to my cohorts talk about the plumber or the furnace guy like they are 5th class citizens. They, at times are idiots. But I don't know many. Most are savvy business men, skilled laborers, skilled planners. Excellent at projection and implementation. And believe it or not, have the people skills to get the job done in their line of work. If you doubt me, then go ahead and do the job yourself and figure out the amount of time (you wasted on your companies dime while you figured all this out instead of working), effort and physical labor it will cost you.
If you are a brilliant person, you will soon realize that the cost/benefit is not so good and that you are going to have a bit of faith after you do your research. I understand that you are an anal person (like me) and need to have ALL your ducks in a row before you release the hounds so to speak. I'm at that point right now myself and am having large problems finding that point of trust as the disparity of information flowing in is arduous at best. But eventually you will find that focal point and pull the trigger. BUT, like I said - if you think little of the industry then do it yourself if you are physically capable of doing it. IF you don't have the time, then well - sounds like you need to hire the right person and have them do it for you.