Work out oven energy cost instantly with clear inputs, formula shown and shareable results.
An oven's element cycles on and off once up to temperature, so average draw is well below the nameplate rating — typically 30-40% duty after preheat. Preheating is the expensive part, which is why batch cooking and avoiding unnecessary preheats save real money.
Oven cost
effective kW = rating x duty cycle (plus preheat allowance); cost = kW x hours x tariff
Yes, roughly 20%. Forced circulation transfers heat faster, allowing a lower set temperature and shorter cooking times.
For baking yes, for roasting often not. Skipping preheat on a roast saves 10-15 minutes of full-power operation with little effect on the result.