Saving Energy in Cooking: Pans

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Heating something up in a pan on the top of the stove is one of the most common ways of cooking. It’s also one of the easiest on which to improve efficiency and make some big savings. Read on..

 

HOW IT WORKS:

Whether it’s boiling an egg, heating up a can of beans or cooking the veg, when you’re warming something up on the stove top, two things are happening.

Firstly heat is going into the base of pan from the stove to warm the food. Secondly, and less obviously, heat is pouring out of the top of the pan.

 

The pan is mostly losing heat through evaporation which results in a cooling of the contents. The higher the temperature, the greater the evaporation effect.

 

In practice, evaporation means we simply turn up the power below it to compensate - ie: use more energy.

 

 

POSITIVE STEPS:

 

  Heat the minimum

 

Water takes a phenomenal amount of energy to raise it to boiling point. Hence an excellent first step when boiling something up is to reduce the amount of water in your pan to the minimum required for the job.

 

So if you boil the peas in say 250ml of water rather than a litre, you'll be reducing the energy requirement by four times. A saving well worth having.

 

 

  Heat the pan, not the room

 

Using the right sized hob ring for the pan can make the difference between all the heat going into the pan or only a part of it hitting its target.

 

If you're cooking on gas, make sure that the flame all hits the bottom of the pan rather than licking up the sides.

 

Do these and you will be using the energy where you want it and not wasting it in heating up the room.

 

 

  Lids

 

The amount of heat escaping through evaporation from the top of the pan can be huge yet can be massively reduced by simply putting on a lid. The lid lets a humid atmosphere build up above the pan drastically reducing evaporation. What this means in practice is that you can turn down the heat – ie: save significant amounts of energy.

 

Think of a pan like your house. Imagine what your house would be like if it had no roof in winter – all that heat going up into thin air! But you could warm it up to comfortable temperature if you cranked up the heat far enough – it’s just that huge amounts of heat would be going straight out of the top of it, and your energy consumption would be literally through the roof.

 

So just like a roof tries to keep in the heat you warm the house with, a lid does just the same on a pan. Think of a lid as your pan's insulation.

 

  The Bonus benefit...

 

Let’s say we’re boiling up a big pan of spuds and haven’t put a lid on – what happens? Aside from having to crank up the heat further than we would with a lid, there’s a whole load of steam coming off...

So rather than turn the kitchen into a sauna we turn on the hob extractor fan. Drawing a hefty 200 Watts (more with the lights on) the extractor works to pump the steam out of the house.

 

BUT it is also pumping loads of nice warm air that your central heating system has worked very hard at producing straight out of the house.

 

This can be worsened dramatically by forgetting to switch the extractor off afterwards. It will sit there for hours merrily consuming power, and pumping your home’s precious heat outside.

 

The same is true of say opening a window to get rid of steam, except that the window doesn’t use 200W and we tend to shut a window sooner than switching off a fan.

 

Of course all this could be avoided completely if the pan of spuds was boiled with a lid on in the first place. Same result, at just a fraction of the energy consumption!

 

 

  Don't reheat, just keep warm

 

Even if you're not cooking, a lid will keep things warm for ages.

 

If you want to see just how effective it is, make a couple of cups of tea and put a lid / saucer over one and leave the other uncovered. Then leave them on the side to cool. Come back to them 10-15 mins later and see for yourself the power of lids!

This can be put to good energy-saving effect by putting lids on any pans / plates that you want to keep warm for later. It might be some second-helpings that you'd otherwise have to reheat.

 

Or say the phone goes just as you're tucking in. You could switch the oven on and put your dinner in there... or instead you could save the oven's 5kW heaters and just put a lid or upside-down plate on top of your dinner.

 

Food kept warm with zero energy consumption.