The efficiency of various cooking methods

Not too scientific this entry, but found a discussion at work in our sustainability forums asking " I've been looking for information about whether it really is more economical to use a slow-cooker than an electric oven or cooker."

This has been bugging me, so I've clamp metered a few different devices to get a rough idea of how much electricity was consumed in my house making similar foods (stews). Amounts were about the same and the idea is to feed my greedy family of 5 (soon to be 6!!)…

1. Slow Cooker. An average of 20W per person for the food cooked (using boiling water at the start)

2. Microwave. An average of 85W per person.

3. Slow Cooker. An average of 100W per person.

4. Electric Hob (ceramic). An average of 240W per person.

5. Oven (electric non-fan). An average of 350W per person.

2 was higher than I expected, but in the 'rest' periods between the two microwave sessions the microwave still consumed power cooling itself down and turning the turntable etc.

3-5 are hampered by longish warm up times and cooking times are the key differentiator between them – longer the cooking time the higher the consumption

Device: Microwave

Cooking Time: 30 mins (10 mins cook, 5 mins rest & stir, 5 mins cook, 5 mins rest & stir, 5 mins cook all at 70% power on a 850W microwave)

Total consumption 425W, 850W per hour , 85W per person (five people)

Device: Slow Cooker

Cooking Time: 8 hours

Total consumption 500W, 63W per hour , 100W per person (five people)

Device: Electric Hob

Cooking Time: 1 hour (mostly low power simmer, seems to be 2.2KW hob)

Total consumption 1200W, 1200W per hour , 240W per person (five people)

Device: Oven

Cooking Time: 1.5 hours (put into cold oven)

Total consumption 1750W, 1160W per hour , 350W per person (five people)

Anyone else done a similar experiment?

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The efficiency of various cooking methods by Adrian Hollister is licensed under a Creative Commons Attribution-ShareAlike 4.0 International

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