Another possible explanation is:

He is really not very good at measuring energy input and heat output. He built something and confused himself into thinking it was producing more energy than it consumes. He took some money from investors to develop the technology. He spent much of the research money, eventually to realize that his device does not, in fact, produce energy. His investors now want their money back and he is concerned they are going to break his legs.

So at this point he has no choice but to maintain his original claims for as long as possible. Appearing now to be bumbling and incompetent may be preferable to appearing accurate and precise with measurements.