To provide a like for like example to support your point @phb
It based the oven cost on 1 hour of use 3 days a week and the slow cooker on 8 hours a day 3 days a week.
To compare a like for like meal/dish, a stew in an oven requires about 1 and 3/4 to 2 hours of cooking, nearly double to double the time used to calculate the yearly cost. This would be nearly double to double the energy cost.
The same product in a slow cooker over 8 hours does not affect the amount of time and thus energy used as per the article (it was calculated on 8 hours of use per day when used).
To cook the same type of suitable meal is thus cheaper in the slow cooker than the oven, by a substantial amount. (not every meal is suitable to be cooked in a slow cooker)
The arguments put by phb and grahroll support the case for Choice to provide more realistic estimates of the relative costs of cooking with pressure cookers, saucepans, ovens, air fryers and slow cookers.
The rather approximate cost per year for three meals a week according to that July '22 article are:
Air fryer $30
Cooktop $44
Oven $106
Slow cooker $59
Note that these are computed costs not measured. The computation includes quite a few assumptions and much variability because not all of each kind of cooker are the same cost to run. Each of these estimates already has a pretty wide error bar due to uncertainty of equipment used and methods employed.
You say you want to get better results. Would this be by doing a computed annual cost for every device tested or actually testing them all out and measuring the power used? That’s a lot of testing.
Choice has already provided a general assessment that the oven is the most expensive and that is hard to disagree with on several grounds. Looking at the rest I do not see how detailed study is worthwhile as it looks like the differences are of the order of a dollar a week. Feeding one sausage to the dog will cost you about that. Letting one lettuce rot will cost you more.
All the other things you could do to save power in your house add up to far more than that. The ways you can save money by the way you cook, the ingredients you use and the way you manage waste are all much more important than that. I don’t see that many people might change the type of gear they use and the type of food they cook for such minor savings - if they exist.
The detailed study would swamp the reader with data that may or may not apply to them, or mean very much, or it might show that there are measurable differences but that they are insignificant. I prefer broader advice such as the Ways to save money on energy while cooking in the kitchen listed at the end as being more applicable and much simpler.
There are various home energy comparisons produced over the past decade including by the CSIRO.
Cooking makes low demands, around 5% of all energy use in an all electric home. Electric ovens do figure in some analysis as one of the largest users of power, however they are only used in most homes for a few hours per week. This is compared with the use of RC Aircon, hot water heating, washers/driers, which all run for many more hours, making them far more significant.
This isn’t about slow cookers but it is relevant to the question of capital cost versus running costs and about computation of power costs for appliances.
An air fryer is cheaper to run than a full oven when cooking some foods, such as crumbed chicken or chips. The reasons for this have been spoken of at some length.
Assume for the moment that you do eat those kinds of foods fairly regularly (say once a week) and that you already have the full oven (like most houses) and use it for that kind of food.
You buy a middle range air fryer based on Choice recommendation for $200. Now you use the fryer once a week instead of the oven and each time you do so you save electricity. This sounds pretty good.
Based on this scenario how long does it take to get back the up front cost of the fryer from your power savings?
The Choice article Which cooking appliances are the cheapest to use? estimates that, when used three times a week, a wall oven will cost from $31 to $65 per year and a slow cooker will cost from $32 to $98 per year. On that basis a $200 air fryer, used once a week, would have a simple payback of at least 18 years - and might actually cost more to run than a wall oven.
