Energy Saving BS

FreeBear

mmmmikey said: Assumptions:

1. 30 minutes per day (as per your question)

2. Air fryer is rated at 1500W (I've had a look and seems fairly typical)

3. Air fryer runs continually for the 30 minutes

4. Air fryer uses half the energy as the oven (this is just a guess but seems resonable or possibly conservative - has anyone measure this?)

You also assume that both an oven and air fryer are consuming full power at all times.

My oven, once up to temperature, cycles on & off. So if the element is 2KW, typical consumption (once up to ~200°C) is around 1KWh. I would expect an air fryer to exhibit similar characteristics - This will impact on your savings calculations and RoI times.

[Deleted User]

FreeBear said:

mmmmikey said: Assumptions:

1. 30 minutes per day (as per your question)

2. Air fryer is rated at 1500W (I've had a look and seems fairly typical)

3. Air fryer runs continually for the 30 minutes

4. Air fryer uses half the energy as the oven (this is just a guess but seems resonable or possibly conservative - has anyone measure this?)

You also assume that both an oven and air fryer are consuming full power at all times.

My oven, once up to temperature, cycles on & off. So if the element is 2KW, typical consumption (once up to ~200°C) is around 1KWh. I would expect an air fryer to exhibit similar characteristics - This will impact on your savings calculations and RoI times.

Not sure really, be good if someone with a Tapo plug or similar can measure this. With the conventional oven (a) you need to let it heat up first (b) you're heating a larger space (c) cooking times are longer hence my "finger in the air" assumption that it takes twice the amount of energy to cook things.

I have a Tefal Actifry which only has a single cooking temperature and seems to run continually, i.e. doesn't cycle on and off - not sure if that is the case with other air fryers. Are they thermostatically controlled "turn themselves on and off things", or do different power levels simply adjust the temperature of the blown air?

ariarnia

we dont have a plug but i think with ours the fan blows constantly but the heating bit clicks on and off. so if you set it to 180 the heat and fan are both on until the space hits temp then the heating only keeps the element/air at that temp for the cooking time. so if you pre heat for 5 mins at 205 at the start then the heating for the food at 180 might not come on much at all. 

[Deleted User]

Pre-heating at 205 and pre-heating at 180 would both use the same amount of energy (until 180 is reached) of course.

Don't get caught in the "turn it up higher to make it heat faster" assumption that many seem to accidentally make.

Spoonie_Turtle

[Deleted User] said:

5. Electricity costs 33p/kWh (that's current price for single rate tariff in East Midlands & may well go up when the EPG ends)

Cost per day:

Airfryer 30/60 * 1.5 * 33 = 24.75p

Electric oven = 24.75 * 2 = 49.5p

Saving per day: 24.75p

So if the air fryer costs £100, it would take 404 days (just over a year) to pay for itself

If the air fryer costs £60 (and there are basic models at that price), it would take 242 days (about 8 months) to pay for itself

And in East England the EPG rate is 35p; using your calculations as a model a £100 fryer would pay for itself within 381 days, and a £60 in 229 days.

Air fryers probably aren't cheaper to run than a gas oven.  But it's logical they must use less energy than an electric oven because there's a LOT smaller space to heat, less food to heat, and it's usually run for a shorter time.  And if you must pre-heat an air fryer, it takes literally a couple of minutes rather than the 10-15 (or more) it takes for an oven.

Alnat1

I wouldn't preheat my fan oven unless it's for something that cooks in 10 minutes or so and I often turn the oven off for the last 10 minutes of cooking time.

ariarnia

[Deleted User] said:

Pre-heating at 205 and pre-heating at 180 would both use the same amount of energy (until 180 is reached) of course.

Don't get caught in the "turn it up higher to make it heat faster" assumption that many seem to accidentally make.

the pre heat button on our model is 205 for 5 mins. one press and it starts then beeps to tell you when to put in the food and set the temp/time you need. i admit i'm lazy and press that. i should set it manually to pre heat at the needed temp and watch the timer for when i should add the food. but i'm not going to and you can't make me

[Deleted User]

I used my Tefal Actifry for dinner this evening and it used 0.43kWh for a 30 minute cook (using cheap battery power of course ), so a fair bit less than my guess above and it must be switching itself on or off or somehow regulating the air temperature. As others have correctly pointed out, although the fan runs continually the element either switches itself on or off or reduces it's output power somehow.

Having done a bit of digging, it looks to me like a typical fan oven has a 2kW element but typically uses 0.87kWh once it's up to temperature to maintain that temperature. I don't know what temperature this is, but assume it be a fairly typical 190C. So if you assume the oven uses full power for 10 minutes as it gets up to temperature that's 10/60 * 2 = 0.33kWh. Then assume that something that takes 30 minutes in the air fryer takes about 40 minutes in the oven (about right in my experience): that's 40/60 * 0.87 = 0.58kWh. Adding the two stage together gives 0.91kWh.

So my revised estimate is that the air fryer would save 0.91 - 0.43 = 0.48kWh per day, or 15.84p at a current cost of 33p/kWh. So a £60 air fryer would pay for itself in 60 / 0.1584 = 378 days and a £100 air fryer 100 / 0.1584 = 631 days.

In my first post on this I suggested that at current EPG prices the air fryer in regular use in place of an oven would pay fr itself in a year or so - I'm now saying that it would pay for itself in a year or two - so not much difference And of course, if unit prices go up in April it would pay for itself quicker.....

markin

What can't you cook in a microwave vs an air fryer?

I looked at air fryer on amazon and every brand had a review with photos of it burn or melted!

Spoonie_Turtle

There are a lot of things that go soggy in the microwave (that aren't really supposed to be soggy).