I need to learn how to do estimates for hvac jobs, what are the major things I should be looking at while doing an estimate? My brother does hvac full time and we're trying to start our own company, I know I could juat ask him be he's always busy, is there a hvac study book? I think I need to get licenced too
I know next to nothing about HVAC.
But I've done a little research and reading on the subject. Seems like it would be a good career, but there are many technical and legal issues to understand and master. In my state a person must have been employed in the HVAC industry for five years before you can even take the test to get certified. The certification test has a legal and technical section. There are mountains of laws to protect the environment, you and your prospective customer.
Start with your local library. It is free, and it is more organized than the Internet. Learn some basic theories, then use the internet to research specific issues and applications.
I do know a little about estimating projects, not HVAC, but a wide variety of personal and professional projects. And I can say with certainty that the "job cost estimation" end of any business is not a good starting position for a "rookie". It takes a lot of experience to recognize the complexities of jobs. Its never the main component of the project that burns you, its the assumptions and "minor" details that will come back to bite you. Annoying things like laws, building codes, coexisting and integration with other systems, tool requirements, availability of parts and even access to the job site.
Read up at the library for free, then have some conversations with your brother. He'll probably have more time to talk if you've done some research first.