I'm interested about these 3 companies who came out and couldn't deliver an answer to the complaint. Are they licenced HVAC contractors? Handyman type of people?
Specifically, did the OP here contact 3 different licenced HVAC contractors and neither one of them had a clue?
An answer without a question is meaningless.
Information without understanding is useless.
You can lead a horse to water............ http://www.mohomeenergyaudits.com