kWh use by an appliance to do a fixed task.

[ericmark]

If I want a baked potato, I have three appliances, the fan oven, the microwave, and the air fryer, I can put an energy meter on the last two, but since the over is hard-wired it is guess work. There is also the question when other items like a pizza is being cooked, which may need the oven for 15 minutes, it is then faster to start the potato in the microwave, and transfer to finish, but would it be cheaper to oven cook.

The debate as to when a cup of coffee has been let to go cold, which is cheaper, reheat in microwave, or dump it and make fresh with one cup boiler, remembering cost of coffee, coffee mate, sweetener, and oat milk.

I tried with my washing machine, and gave up, the machine weighs the clothes, so use twice on the same program and it will use a different amount. And when solar is good, I have put dishwasher, washing machine and tumble drier on, and either got timing wrong so used over the 5 kW the inverter can provide, or they have not used anywhere near enough to stop exporting.

Some things don't matter, if I want to watch TV, I will watch TV, I suppose could compare free-to-air and freeview but 20 watts in the grand scheme of things not worth worrying about.

One has to also consider speed, to clean the whole floor with an old Dyson vacuum it may draw 1000 watts, but job done in less than ½ hour, mess around with new battery powered rubbish, and it takes 2 hours to do the same job, well not as good of a job, and not worked out the cost to charge the battery, there must be losses.

So from baking a cake to mowing the lawn, my battery for trimmer may be 40 Wh but how much to charge it? I do have plug in energy meters, but it takes time to move them appliance to appliance. And how do you use the info it is on the tumble dryer at the moment, I have not a clue how many times my wife has used it, seems likely from first graph 4 times in April, so 70p per use? Well not really the monitor set to 31.31p per kWh and really since used in the day when sunny, cost 15p/kWh in lost revenue from solar, so 35p loose that and more if one bird deposits lime on the clothes meaning they need rewashing.

Nearly every appliance has the Watts or Kilowatts marked, if not they are marked in amps, but trimmer battery charger marked 200 watts, it takes around 1.5 hours, and the battery rated 40 watt/hour, so I really hope it does not take 200 watts.

Fridge, freezer, both marked as how many kWh/year, and not switched on/off, so great, but rest nothing to say how many Joules, Calories, or Watt/hours they use, so is the air fryer cheaper to run?

 

[Wayners]

If I understand. I'm no expert..

Energy to heat on many appliances is about the same.
It don't matter what you use if the appliance is similar as they use the same energy to create heat.
So an air fryer is the same as an oven except, the oven takes more energy to heat the larger space to temperature and keep it going.
Microwave is quicker but uses more energy.
Less efficient in some cases as some waves miss the food.
Also a baked potato is way better eating when cooked in the air fryer than a microwave. I won't use a microwave for anything other than warming food.
I think it depends what you're cooking and how big it is.

To answer. One or two backed potatoes would be better In air fryer.
For cost and taste imo

 

[ericmark]

We have moved to air fryer, I noted the principles that it works on, where the careful scrupled base to the pan causes the rapid air movement around the food, then my wife uses a silicon basket and completely messes up how it should work. Without her silly little rubber things, it is far faster to the fan oven, but with silly lumps of rubber about the same as a fan oven, but clearly a lot smaller.

The idea is twofold, if it uses less energy it will cost less, and second if it uses less energy then the kitchen will keep cooler. But these elements use a mark/space ratio to heat the area, so no good just reading the plate.