Re: density
No, no they don't. They use spring loaded mechanical switch.
Why on earth would my fridge manufacturer reject a tired and tested cheap reliable effective design in favour of a less effective option that costs more and consumes more energy? It doesn't make any sense at all.
Seriously, I have investigated this extensively. It's all PIRs these days. I'm worried you are just embarrassing yourself here. Some manufacturers have even produced retro-fit kits to upgrade older fridges
Biting the hand that feeds IT
