The bill arrived and I assumed a meter fault. It wasn’t a meter fault. It was August, and it was me, running a modern inverter unit the way you’d run a 1990s one.

So I spent a month testing things, with a cheap plug meter on the indoor unit and a note on the fridge. Here’s what moved the number and what didn’t.

Switching it off when I left the room was the expensive habit

This is the one that surprised me. An inverter compressor is designed to run continuously at low speed once the room is at temperature, and low speed draws very little. Every time I killed it and came back an hour later, the unit had to pull the room back down from scratch, which means running the compressor flat out. Flat out is where the consumption lives.