Why slow cookers could save more on winter bills than air fryers for some families, according to energy auditors

Amelia Foster • January 22, 2026 13:52

The thermostat had just clicked on for the third time that morning when you caught yourself doing the quiet winter maths again. Kettle, tumble dryer, oven, lights, the mysterious “other” on the bill that never quite adds up. The air fryer sits on the counter like a small promise-you’ve heard it’s cheap to run, practically saintly compared with the oven. The slow cooker, if you even own one, feels old‑school by comparison.

You scroll past a post where someone swears their stew cost “pennies” in the crockpot, then another boasting that a whole roast chicken in the air fryer was “cheaper than the bus fare to town”. Both can’t be right for everyone. Somewhere behind the hashtags, people who actually measure electricity for a living have been quietly logging what these gadgets do to real bills.

What independent energy auditors keep finding is awkward for the hype: for some households, the slow cooker often wins the winter savings race. Not per hour, not per gadget, but per meal, per portion, per actual week of eating when the heating is already fighting the cold.

The difference comes down to how you cook, how many people you feed, and what you would have used instead.

Why “cost per hour” misses the point

A slow cooker might use just 150–250 watts on low; an air fryer typically pulls 1.4–2 kW. On paper that makes the air fryer look greedy. In practice, it’s like comparing a bedside lamp with a powerful spotlight without asking how long they’re on or what they’re lighting.

Energy auditors always work in kilowatt hours (kWh): power × time. That’s what your bill charges for. A 200 W slow cooker running for 7 hours uses about 1.4 kWh. A 1.7 kW air fryer running for 35 minutes uses around 1 kWh. Very different stories if you only glance at the plug rating.

The trick is this: you don’t eat “an hour” of cooking. You eat meals. The real question is “How many complete meals, for how many people, for how much total energy?” Once auditors frame it that way, slow cookers start looking surprisingly sharp-especially in winter.

What energy auditors actually see in homes

When audit teams go into UK homes, they don’t just lecture about turning lights off. They plug monitors between appliances and the wall, then watch what happens over weeks: what’s used, how often, and instead of what.

Some patterns keep repeating:

Air fryers are brilliant at replacing an oven for small, dry jobs: chips, a tray of nuggets, a couple of chicken breasts, reheating leftovers.
People rarely cook long, wet dishes in them-soups, stews, lentils, porridge-because the baskets are shallow and the stirring is constant.
Slow cookers, by contrast, almost always come out for one‑pot, high‑volume meals: stews, chilli, curry, bean dishes, pulled meats, porridge for a crowd.

On a monitor graph, this looks like two different shapes of energy use:

Short, steep spikes for the air fryer.
Long, low hums for the slow cooker.

When auditors total it up per completed meal, especially for families of three or more, the humble slow cooker often matches or undercuts the air fryer on cost-and replaces more expensive habits like long oven roasts and multiple hob rings going at once.

When a slow cooker can beat an air fryer on winter bills

The surprise is not that slow cookers are cheap; that’s been known for years. It’s that, for certain patterns of cooking, they edge past the air fryer as the more economical choice. Auditors see that most clearly in a few scenarios.

1. Bigger households and batch cooks

Imagine a 3–3.5 litre slow cooker, 200 W on low, running for 7 hours on a beef and lentil stew.

Energy used: about 1.4 kWh.
Portions produced: easily 6–8 generous servings.

At common UK electricity prices, that often works out at a few pence per portion. You might eat four portions that night and freeze the rest for another day, with no extra cooking cost.

Now try to get the same volume through a medium air fryer. You’ll either:

Cook in two or three batches (each needing pre‑heat and cook time), or
Give up and use the oven or hob for the “liquid” part of the meal.

Once the air fryer needs multiple runs, its per‑meal advantage shrinks quickly. The slow cooker does the whole pot in one go, quietly, while you’re at work.

2. Cheap cuts and long cooks

Tough, inexpensive cuts-shin, brisket, pork shoulder-need time. On the hob or in the oven, that often means several hours at a respectable power draw. Auditors regularly log 2–3 kWh for a low, slow oven braise.

The same cut in a slow cooker:

Sits at a fraction of the power for the same or better tenderness.
Doesn’t demand an active flame or hot box heating the whole kitchen.

This is where winter bills really feel it. You get warming, protein‑rich, fridge‑clearing meals without running the oven for an afternoon.

3. Stews, pulses and porridge instead of “oven food”

Air fryers shine with the very foods that are priciest per kilo: breaded fish, frozen chips, convenience bakes. Slow cookers shine with the things that are cheapest: dried beans, lentils, seasonal veg, oats.

From an auditor’s view, price per kWh is only half the savings picture. The other half is what that appliance nudges you to cook.

A big pot of chickpea curry plus rice can feed a family for less than a single box of frozen goujons.
Slow‑cooked porridge overnight can replace pricey branded cereals.

The slow cooker doesn’t just use less energy than your oven; it steers you towards ingredients that stretch your food budget further.

4. Off‑peak tariffs and “set and forget” days

On Economy 7 or similar tariffs, some households pay less for electricity overnight. A slow cooker can quietly take advantage of that:

Load it late evening.
Run most of the cook during cheaper hours.
Reheat or keep warm briefly at full price if needed.

An air fryer’s short, sharp bursts are harder to shift away from peak times; you tend to use it when you’re actually cooking. Over a winter, that timing difference shows up on the bill.

When the air fryer still wins (sometimes by a lot)

None of this makes the air fryer a villain. For other households, the auditors’ data still crowns it king.

You see that clearly where:

One or two people share a home and cook small portions.
The air fryer is used instead of heating an entire large oven for a single tray.
Meals are mostly dry, quick items: chips, fish fingers, small joints, roasting veg.

In those cases, it’s not uncommon for an air fryer roast to use half to two‑thirds of the energy of a comparable oven job. The savings are real, and they repeat several times a week.

Auditors also note behaviour: people with air fryers are more willing to fully cook from frozen at home instead of ordering in, which nudges food spending down even if the electricity use per meal is similar.

So yes, the air fryer can be a winter ally-just not automatically the champion for every family, every recipe, every bill.

Simple rules to choose the right gadget for the job

Think less in terms of “Which is cheaper overall?” and more “Which is cheaper for this kind of meal, for this many people?”

Broad rules of thumb auditors suggest:

Use the slow cooker when…
- You’re making stews, curries, chilli, pulled meats, beans, porridge.
- You want 4+ portions or plan to batch cook.
- You’d otherwise run the oven or several hob rings for hours.
Use the air fryer when…
- You’re cooking for 1–3 people.
- The food is relatively dry and compact (trays, joints, small bakes).
- You’d otherwise turn on a full‑size oven.
Avoid both when…
- The hob and a lid will do the job quickly (e.g. pasta, quick stir‑fries).
- You’re tempted to run either almost empty “just because it’s there”.

Let’s be honest: nobody is going to spreadsheet every dinner. A couple of simple defaults, stuck on the fridge, get you most of the savings with almost no thought.

Tiny tweaks that make slow cookers even cheaper

Energy auditors see the same handful of mistakes over and over. A few quiet corrections can trim your winter costs further:

Match the size to the job.
A 6.5 litre giant, half‑full twice a week, wastes more energy than a smaller pot brim‑full for the same number of portions.
Cook on low where possible.
Many dishes that say “4 hours on high” are just as happy with “7–8 hours on low” for similar total energy, often with better texture.
Stop lifting the lid.
Every peek dumps heat; the element then runs harder to recover. Trust the recipe, and your nose.
Use it for sides too.
A slow cooker full of jacket potatoes or root veg avoids firing up the oven just to “go with” something else.
Cool and store smartly.
Once cooked, portion straight into containers. Reheating a small portion later in the microwave is usually cheaper than keeping the cooker on warm for hours.

These aren’t heroic lifestyle changes. They’re the kind of half‑conscious habits that quietly shift the shape of your bill across a cold season.

A quick side‑by‑side: what auditors compare

Below is a simplified snapshot of how auditors often frame things. The numbers are illustrative, not exact for every model, but they show the pattern.

Appliance & scenario	Typical use case	Rough energy per meal*
Slow cooker, 3–3.5L on low	6–8 portions of stew/chilli/beans	~1.2–1.6 kWh total (≈ 0.15–0.25 kWh per portion)
Air fryer, medium basket	2–3 portions of “oven‑type” food	~0.7–1.2 kWh per batch (more if you need two batches)
Full‑size electric oven	Family traybake or roast	~1.8–2.5 kWh for 45–60 minutes

*Assuming typical UK plug‑in readings from audit work; actual figures vary by model, temperature, and how full you pack the appliance.

The takeaway isn’t that one device is “good” and the others “bad”. It’s that slow, steady heat feeding many mouths can rival or beat fast, fierce blasts feeding a few.

The quiet psychological win

There’s a softer side to all this that the kWh charts don’t show. A winter slow‑cooker habit doesn’t just shave pence; it changes the feel of the season.

Knowing that dinner is ticking away for pennies while you’re out or working cuts through that low thrum of bill anxiety. Coming back to a warm kitchen that smells like effort you didn’t have to make is its own kind of insulation.

For some families, the air fryer will still be the star player. For others, especially those leaning into big pots, cheap staples and batch cooking, the slow cooker quietly takes the lead-on the counter, and on the bill.

The trick is not to worship either gadget, but to let the auditors’ maths nudge your habits: fast heat for small, crispy things; slow heat for big, saucy ones. The more your winter meals fit that simple map, the less your statement will sting.

FAQ:

Is a slow cooker always cheaper than an air fryer?
No. For small, dry meals for one or two people, an air fryer often uses less energy than a slow cooker making the same food in a big pot. Slow cookers tend to win when you’re cooking liquid, high‑volume meals and replacing long oven or hob sessions.

What size slow cooker is best for saving money?
For most UK families, 3–4.5 litres is a sweet spot: big enough for batch cooking, small enough to run efficiently when full. Very large pots often run half‑empty, which dilutes the benefit per portion.

Does keeping a slow cooker on ‘warm’ use a lot of energy?
‘Warm’ is lower power than cooking mode, but it still adds up over hours. It’s usually cheaper to cook, switch off, then reheat individual portions in the microwave than to keep the whole pot hot all evening.

Are plug‑in energy meters worth buying?
For under £20, a basic plug‑in monitor lets you see exactly what your appliances use. Auditors rate them highly for cutting through guesswork and helping people spot which habits actually move the bill.

If I can only buy one, should I get a slow cooker or an air fryer?
If you mostly cook stews, curries, beans and want to batch cook cheaply, a slow cooker is likely to save you more. If you’re a small household that loves “oven food” and rarely does big pots, an air fryer will probably earn its space first.