Find the cause and prevent that scenario from happening again.

I just spoke with my neighbour. Various safety officials investigated, but couldn't pinpoint any defect. One possible culprit, they suggested, was rodents who may have removed insulation for nesting. (They've certainly done that with my vehicles. Half removed the firewall sound deadening from one. And nothing like finding your Stuttgart V-8 buried in shredded grass!)

have pool / spa heater checked twice a year to prevent this from happening ! Looks like a rodent was building a condominium.

Wow, my theory is use that SOB weekly to have a nice beverage with the wife and rodent move in is unlikely.

Hope every one was ok from that fire.