Compare pressure cooker running cost with other methods.
A pressure cooker saves energy two ways at once. It cuts cooking time dramatically, because raising the pressure raises water's boiling point to about 120 C, and it draws little power once it gets there — the sealed vessel loses almost no heat, so the element only cycles at roughly a quarter duty to maintain pressure. An oven by contrast heats a large uninsulated cavity, loses heat continuously through the door and walls, and cycles at around half duty for two hours or more. The result is commonly an 80 to 90 percent energy saving on braises and stews, which is a far bigger gap than most appliance comparisons produce.
Pressure cooker energy
kWh = (W / 1000) x (come-up hours x 1.0 + pressure hours x 0.25)
Oven energy
kWh = (W / 1000) x hours x 0.5
A sealed insulated vessel loses very little heat, so the element only has to replace that small loss to hold pressure. The come-up phase is where nearly all the energy goes; after that the duty cycle drops to around a quarter, which is why longer pressure times add surprisingly little cost.
No. Pressure cooking excels at braises, stews, beans, stocks and tough cuts — anything that would otherwise need hours of moist heat. It cannot roast, brown or bake, so for a joint that needs a crust or anything requiring dry heat the oven is not optional and the comparison does not apply.