about 10,000 KWh
To find kWh a time frame has to be given. That is what the h in kWh stands for.
About 3 kWh's of heat are created for every kWh of electricity it consumes
In ten hours, a 200W bulb will use: 10 * 200 = 2000 Watt-hours = 2 kwh
The fan has a rated load of 2 kW. It is this wattage times the amount of hours the fan is used times the cost of a kWh in your area that the cost is based on.
none, if it is unplugged
That depends on the type and make of Oven.
100 kWh
about 10,000 KWh
To find kWh a time frame has to be given. That is what the h in kWh stands for.
Look on the manufactures label on the fan. Find the amperage and voltage of the device. Multiply these two values together to find the wattage of the device. If the fan operates 24 hours a day, take the wattage and multiply it by the wattage of the fan. This will give you the total wattage that the fan will use in a day. To take it a step further take the total and divide it by 1000 and this will give you the kWh the fan uses. Find out what you are charged by the utility company and multiply the kWh by this number. This will tell you how much it costs to operate the fan for a 24 hour period.
About 3 kWh's of heat are created for every kWh of electricity it consumes
In ten hours, a 200W bulb will use: 10 * 200 = 2000 Watt-hours = 2 kwh
10 amps at 120 volts is 1200 watts or 1.2 Kw, so in 1 hour it will use 1.2 Kwh
You can do this in either a conventional or a convection oven. If you use a conventional oven, I would rotate the roasting pan half way through the cooking process to compensate for any hot spots in the oven. If you use a convection oven (with the fan), cooking is more even because the fan blows the hot air around the food, but you have to remember to reduce cooking temperatures 50 degrees if you leave the convection function on.
The fan has a rated load of 2 kW. It is this wattage times the amount of hours the fan is used times the cost of a kWh in your area that the cost is based on.
Generally you deduct temperature not time for a fan assisted oven. For a recipe saying 200o use 180o on a fan assisted. Obviously all ovens are different but this should work.