Is A House Wired Ac Or Dc

What is going on with my house’s ac power? is there something using my Standby compact wired modules low power dc ac Concealed wiring

I was helping my dad change the AC unit in his house and found this

Wiring choice cablefail I was helping my dad change the ac unit in his house and found this Compact wired ac/dc modules with low standby power

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Complete home on 12volt dc system with concealed wiringHvac belen .

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Compact wired AC/DC modules with low standby power

Complete Home on 12Volt Dc System with Concealed Wiring - YouTube

I was helping my dad change the AC unit in his house and found this

What is going on with my house’s AC power? Is there something using my