What does a rangehood / extractor cost to run?

A rangehood is a low-wattage appliance, usually just a fan and an LED light, often under 100W, so it costs very little to run directly. Its real value to your power bill is indirect. Clearing steam and cooking moisture out of the kitchen helps keep the house dry, which reduces the damp that drives up heating and dehumidifier use in NZ homes.

That indirect angle matters more than the wattage in a New Zealand context. Damp is the enemy of a warm, cheap-to-heat home. A room full of moisture feels colder at the same temperature, so you crank the heating harder, and a dehumidifier left running for hours is a far bigger line on the bill than the rangehood fan ever will be.

The trade-off in winter is that a ducted rangehood vents warm indoor air outside, so running it longer than needed throws away heat you have paid for. Leave it roaring for an hour after the pot has come off the boil and you are effectively pumping your heating out through the wall for the sake of a fan that costs almost nothing to spin.

The sensible balance is to run it while you cook anything steamy or smoky, and for a short while after, then switch it off. Long enough to clear the moisture, not so long that you are throwing away warm air. A minute or two past the last of the steam is plenty; you are venting water vapour, not trying to change the air in the whole house.

The other quiet cost is the light. Many people leave the rangehood LED on as under-cabinet kitchen lighting all evening. At LED wattages that is trivial, but it is the kind of thing worth knowing rather than assuming the hood is off when the fan is silent.

As an appliance cost the rangehood is negligible, and there is nothing to agonise over here. As a moisture-control tool it does more than its wattage suggests, so use it freely while you cook and it will earn its keep by taking load off the appliances that actually move your bill. Drop it in the calculator and you will see it barely registers.