Air fryer vs oven vs slow cooker vs microwave: which is cheapest to run?

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Quick answer

For small portions and reheating, the microwave is usually the cheapest to run, followed by the air fryer, because they cook quickly and heat a small space. A full-size electric oven costs the most per use, but it’s efficient when you fill it with several dishes at once. A slow cooker uses little power per hour but runs for hours, so it’s best for big batches of cheaper cuts. At the current cap rate of 26.32p per kWh, the cost of one use ranges from a few pence to around 50p.

How we worked out the costs

Running cost depends on two things: how much power the appliance draws and for how long.

Cost = power (kW) × hours used × price per kWh

We’ve used the Ofgem price cap average Direct Debit rates for 1 October to 31 December 2026: 26.32p per kWh for electricity and 7.97p per kWh for gas. The power ratings and cooking times below are illustrative examples, not measurements of any particular model. Check the rating plate on your own appliance and swap in your figures.

Most cooking appliances have thermostats that switch the heating element on and off once they’re up to temperature. So the “full power” figures below are an upper estimate; real-world costs are often lower.

Running costs at a glance

Appliance	Example power	Example cooking time	Energy used (full power)	Cost per use (upper estimate)
Microwave	1kW input	6 minutes	0.10 kWh	2.6p
Kettle	3kW	3 minutes	0.15 kWh	3.9p
Air fryer	1.5kW	20 minutes	0.50 kWh	13.2p
Electric hob ring	1.5kW	20 minutes	0.50 kWh	13.2p
Slow cooker (low)	200W	8 hours	1.60 kWh	42.1p
Electric oven (with 10 min preheat)	2.5kW	50 minutes	2.08 kWh	54.8p
Gas oven (with 10 min preheat)	2.5kW of gas	50 minutes	2.08 kWh	16.6p

A few things jump out:

• Small, fast appliances win for small meals.
• The slow cooker isn’t automatically the cheapest. Over eight hours it can use more energy than an air fryer, so its value comes from cooking a large batch in one go.
• Gas ovens cost much less per hour than electric ones because gas is about a third of the price per kWh.

Appliance by appliance

Microwave

Cheapest for: reheating, porridge, steaming veg, jacket potatoes (or start them in the microwave and crisp them in an air fryer or oven).

Microwaves heat the food directly and work in minutes, so they almost always win on cost for single portions. Note that the power on the box (for example 800W) is usually the cooking output; the electricity it draws is higher, so check the rating plate.

Air fryer

Cheapest for: small batches of chips, roast veg, chicken pieces, reheating things you want crisp.

An air fryer is a small fan oven. It heats a much smaller space than a full oven and often needs little or no preheating, so cooking times and energy use drop for one or two portions. If you’re cooking for a family and need several batches, the savings shrink. Browse air fryers on Amazon and compare basket size with how many people you cook for.

Slow cooker

Cheapest for: big batches of stews, chillis, curries and soups using cheaper cuts and pulses.

Slow cookers draw little power but run for hours. They’re most cost-effective when you fill them and freeze extra portions, which cuts both energy and food costs. They also beat a conventional oven for long braises: three hours in an electric oven averaging even 1kW would use about 3 kWh (79p), compared with 1.6 kWh (42.1p) in our slow cooker example. Browse slow cookers on Amazon. Our guide to batch cooking and freezer meals has a week of ideas.

Electric oven

Best value when: you fill it. Roasting a tray of veg, baking potatoes and cooking a pie at the same time spreads the cost across several meals. Avoid preheating for longer than needed, and keep the door closed (each opening lets heat out).

Gas oven and hob

Gas is much cheaper per kWh than electricity (7.97p vs 26.32p), so gas cooking often costs less per hour even though gas ovens lose more heat. Use the right size ring for your pan and keep lids on.

Electric hob

Lids on pans, matching pan size to ring, and turning down to a simmer once boiling all reduce use. Induction hobs heat the pan directly and are quick, but replacing a hob just to save energy rarely pays back fast.

Which should you use for what?

Meal	Cheapest typical choice	Why
Reheating one portion	Microwave	Fastest, heats the food only
Chips or nuggets for one or two	Air fryer	Small space, little preheat
Family roast dinner	Oven, filled up	Several dishes share the heat
Stew or chilli for 6 to 8 portions	Slow cooker	Low power, batch to freeze
Pasta or rice	Hob with lid, kettle-boiled water	Kettle heats water quickly
Jacket potato	Microwave, then crisp in air fryer	Cuts the long oven time

Ways to cut cooking costs further

• Batch cook and freeze. Cooking four portions takes nearly the same energy as cooking one.
• Boil water in the kettle before adding it to a pan.
• Cut food smaller so it cooks faster.
• Use residual heat. Switch the oven or hob off a few minutes before the end.
• Keep appliances clean. A clean air fryer basket and microwave work more efficiently.
• Defrost in the fridge overnight rather than using the microwave’s defrost setting when you can plan ahead.

Is it worth buying a new appliance to save money?

Do the maths first. If an air fryer saves you around 40p each time you’d otherwise use the electric oven for a small meal (using the upper estimates above), you’d need to use it many times to cover its purchase price. That can still make sense if you cook small meals most days. If you rarely use the oven for small portions anyway, it may not. Watch for deals during Black Friday if you’ve already decided to buy.

Sources

• Ofgem: Changes to energy price cap between 1 October and 31 December 2026
• Ofgem: Energy price cap unit rates and standing charges
• Energy Saving Trust: How to save energy in the kitchen
• GOV.UK (Food Standards Agency): How to chill, freeze and defrost food safely