Is your slow cooker a secret energy-saving hero?

Slow cooking just means cooking at a low temperature (below 100°C/212°F) for many hours.

You can slow cook in an oven using a lidded dish, just by turning the temperature down low. A standalone slow cooker, with the heat source built into the base, uses less electricity than leaving an electric oven on all day – but how much less, and how should you use it? 

Slow cookers are great for time-shifting. You put ingredients in the pot at breakfast time, and the slow cooker gently heats them all day, turning them into a delicious dinner. You can cook pretty much everything in a slow cooker – from porridge through to dessert.  

But there are also scientific reasons why cooking low and slow improves certain dishes. The connective tissues in tougher cuts of meat, such as oxtail or lamb shank, break down at low cooking temperatures to release gelatine, for a moist and tender result. 

Slow cooking is best compared with an oven, not a hob, because hobs are best for quick meals, like boiling pasta or cooking an omelette.

With this in mind, Joanna O’Loan, knowledge manager at independent organisation Energy Saving Trust, has compared a slow cooker with an electric oven, looking at costs based on typical meals cooked using each appliance. 

However, before choosing an appliance, consider what you’re cooking and how many people you’ll be cooking for. 

The good thing about slow cookers is that they are fairly affordable for a kitchen appliance, starting from as little as £20 for a 3L model to up to hundreds if you’re looking at a multi-cooker. 

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Dunelm Mill Chalkboard Slow Cooker

RRP: £20

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Ninja Speedi 10-in-1 Rapid Cooker, Air Fryer and Multi Cooker

RRP: £214.51

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Lots of brands also produce them – you can pick them up from your local supermarket or spend the pennies with a Ninja or Green Pan slow cooker. 

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Green Pan 6L Slow Cooker

RRP: £200

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“An oven’s larger size means you can fit a lot of food in at once,” says O’Loan. “So when cooking larger quantities – for example, when batch cooking or cooking for a large group – using your oven could be the best value for money.” 

Don’t simply compare wattages between a slow cooker and an oven, though, as that could be misleading. Ovens only use their rated peak wattage while heating up, and most of the time when you’re slow cooking in an oven at a low temperature it’s ticking along, using much less energy.

This is particularly the case if it’s an efficient model and you don’t open the door too much. If you have a smart meter, you can see energy costs for yourself while cooking and make an informed decision on savings. 

If you want to save money, look for a slow cooker with the lowest wattage.  

Kathryn Farrell, cookware buyer at Lakeland, explains: “Always check the wattage if energy saving is what you have in mind. This isn’t always the smallest in size, which fools many people! So don’t compromise by using a small slow cooker when you could use a larger one for the same, or only slightly more, energy, and produce more food in one go.” 

Energy efficiency matters, but it’s not the only money-saving aspect of these one-pot wonders. It’s not just the appliance, it’s what you do with it that counts. 

Buy a large capacity slow cooker, which is anything over 6l (around 10 ½ pints) and you can batch cook meals, saving spare portions for another day. Reheating those extra portions when you need them uses a fraction of the energy of cooking from scratch – and it saves you time, too. 

But only use your slow cooker for the optimum time needed. “You can save energy by avoiding leaving it on longer than necessary, or use the low setting if you need to leave it on for longer,” says O’Loan. 

Slow cookers also offer convenience. If Friday Morning You is organised enough to put ingredients in the pot and press one button, Friday Night You will be thankful. Piping hot dinner is a gift to yourself. If your slow cooker cuts out a few takeaways, it will pay for itself, and save you money, fast. 

Know yourself – buy a slow cooker if you know you’ll use it. It will save you money in several different ways, by transforming what you cook as well as cooking it more efficiently.  

But if you’re not the kind of person who will put dinner ingredients together in the morning, look for faster alternatives, such as a pressure cooker. These work like a saucepan but cook food faster – ideal for quick dinners and great for veggies.