We have used heat for two units and it worked well, the problem is that the heaters we use run hot. I was at a trade show and there was a company with a $15,000 heat system. It did everything.
The heater would only heat to about 150 degrees not the scorching heat of our unit.
They had wired temperature probes, not wireless. and they had fans that were heat protected.
I could not justify the price for my complex but I can see a group of landlords going together to buy one,
we have two maybe three pest companies that have this system and they charge $750 a day for treatment.
chemicals only work so far, and soon the bugs will be immune to that.
we shopped around and found different companies do it differently. we also removed any warrantee from the company and now we are charged $150 per unit.
seems to work but you have to also be aggressive in moving fast.
Sam