KNX is a smart building system. If your mechanical or electrical engineer isn’t familiar with it or doesn’t feel they are up to it go to the vendor that told you about it in the first place. They will have persons, firms, and contractors that can handle this system.
Be aware that many groups that tell you about systems such as KNX have a financial incentive in specifying these systems. This is why I recommend going through an engineering firm. They will design it based upon the criteria you establish and building codes only. They have no interest in whether you want to buy their products.
MKDesign 