By 'loss leader' I did not mean 'free.
My mistake.
Your timing for this service is good, with the cost of energy now on everyone's mind. I think the challenge is to produce a report that the customer views as a product, in itself.
My examples are thermal imaging, which produces a really nice report. The pictures are understandable by everyone and the hot spots are dramatic. Compare that to power factor correction, which can only be sold to an accountant.
So, I wonder what the survey involves. Ammeter or wattmeter reading? How much detail? How can a report be packaged so the customer understands it?