I can see how it sounds like that (and I take it you're being humourous). It's a mid-terrace house, which means that the side walls abut onto the neighbours' h

I can see how it sounds like that (and I take it you're being humourous). It's a mid-terrace house, which means that the side walls abut onto the neighbours' houses. The side walls are much bigger than the front and back. So not much of the external walls are exposed to the external environment, which is why it behaves like a cave. To be clear, it's not like a heat-pump; it just maintains a reasonable temperature. Did Maxwell's demon perhaps live in a cave?