xkcd #3099: Neighbor-Source Heat Pump
Title text:
The installation of the pipes on the inside of the insulation can be challenging, especially when the neighbor could come home at any minute.
Transcript:
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Source: https://xkcd.com/3099/
Same. We live between two floors. Heat rarely is put on, because stove, fridge and dishwasher are enough to supplement what the sandwiched apartments floors already provide