Your refrigerator/freezer combo is the biggest energy consumer among all of your appliances – seriously. It gobbles down around $100 in energy each year. Even worse, it’s often home to lots of wasted food – leftovers forgotten and allowed to spoil and so on.

To put it simply, your refrigerator and freezer are money sinks. They’re expensive in the first place, gobble down energy like there’s no tomorrow, and sometimes ruin the food that’s inside. What’s a thrifty person to do?

Here are a few simple techniques to overcome and reduce these costs with surprisingly little effort.

Clean the coils regularly.

The coils on the bottom and the back of your refrigerator tend to gather dust over time. As that dust builds up, your refrigerator doesn’t run as well as it used to. The condenser kicks on more often, it has to work harder, it eats up more energy (costing you), and it wears out quicker (costing you).

So, do a little bit of maintenance once a year or so. Pull out your refrigerator and dust the coils in the back and underneath the device. Use a low-power vacuum to make sure there’s no excess dust floating around in the place where the refrigerator normally sits. Doing this little thing will cause your refrigerator’s condenser to work more efficiently – it won’t kick on as often (trimming your energy bill) and it won’t wear out as quickly (saving on your repair and replacement costs).

Fill your empty milk or juice jugs with water, then stick ’em in the freezer.

A freezer, whether it’s a deep freezer or a freezer housed in the same appliance as a refrigerator, functions best when it’s really full, as the cold items help keep other items cold and maintain the low temperature.

But how can you keep it full without stocking it with a bunch of food that you may or may not eat? If you’re not into filling your freezer with food, fill it with water.

It’s simple. Take an empty milk jug (or juice jug), rinse it out, then fill it about 75% full with tap water. Stick that jug in the freezer and just leave it there. It’ll freeze, then it will help keep the temperature of your freezer low over the long haul, causing your freezer to kick on a bit less often to keep your items cool.

Even better, you can directly use these jugs when you need a lot of ice. You can either stick the jug entirely in a cooler or smash it open and use the broken ice pieces to your desire. Works like a charm – we do it all the time!

Start a miscellaneous vegetables box.

We cook a side dish of vegetables with almost every meal we make, and we often have just a few spoonfuls of leftovers. Often, these wind up in the compost bin, but that’s not particularly efficient – I’d rather throw actual waste in the compost bin, not food.

Our solution is a clever one. We just stuck a small resealable container in the freezer. Whenever we have any sort of leftover vegetables, we just spoon those veggies into that container. When the container is full, we boil up some water, add some spices, toss in some diced chicken breasts (and some stock if we’ve got it), then add the vegetables and let it all boil together.

Boom – really inexpensive (and delicious) chicken soup that’s different every time you make it. You can thicken the water/broth with a bit of corn starch to make it more like a stew if you want.

This is a killer way to not waste leftover vegetables, add volume to your freezer, and produce a very delicious and simple meal for pennies.

Pull the fridge forward an inch or two.

In many kitchens, refrigerators are pushed back as close to the wall as possible in order to eke out a few more inches of floor space. Those few inches are really expensive.

If your refrigerator is pushed back as far as possible, pulling it forward one inch can reduce the energy usage of the refrigerator by as much as 40%, and you’ll barely notice the difference in your floor usage. Subsequent inches help, but aren’t quite that effective.

Stick a thermometer in your fridge.

Ideally, the temperature in your refrigerator holds pretty steady around 37 to 40 degrees Fahrenheit (3-5 C). We keep ours at almost exactly 38, and it’s almost perfect for us.

If you keep it below 37 degrees, you’re pushing up against the freezing point of water, which can affect food quality and burns a lot of extra energy. If you keep it above 40 degrees, it can affect food quality in a different way, leading towards spoilage. The range between the two is optimal – and it’s also optimal for refrigerator efficiency, since devices are designed to run in this range.

How can you be sure you’re hitting that sweet spot? Get out a thermometer, put it in a glass of water, then put that cup in your refrigerator for 24 hours. Check the temperature afterward – that’s the true temperature of your fridge. Adjust upward and downward as needed – you might be surprised how much your temperature is off.

A freezer has a different optimum temperature – 0 to 5 F (-18 to -15 C). You can get this temperature by putting your thermometer between two frozen items for 24 hours.

Chuck your refrigerated leftovers.

Ah, the refrigerated leftover. Inevitably, some of those items wind up getting pushed to the back and forgotten, left there to slowly decompose, become a potential breeding place for yeasts and molds, and potentially contaminate other foods.

So chuck ’em. One easy way to do this is to have a handful of washable markers near your fridge. Doodle on any new item with a color for each day – say, purple for Monday, red for Tuesday, etc. Then, when you’re glancing in the fridge on Sunday, you know you can chuck anything with a red or purple mark on it without thinking at all.

Just mark on the Saran wrap, aluminum foil – even on the rim of a plate. Once you get into the routine, it works really well, makes leftover cleanup really easy, and keeps nasty things from growing in your fridge.

Go hardcore – build your own and reduce energy consumption by 90%.

Willing to go way outside the box to trim your home energy consumption? You can build your own chest refrigerator with a few simple modifications to a chest freezer and cut your energy use by about 90% over a typical standup fridge.

With clever rack systems in the chest fridge, they can be pretty convenient. I’m tall, so I actually quite like chest freezers, as I have no problem reaching clear to the bottom, but I can see how this might not be easy for some.

I’ll admit it – I’d love to have such a fridge if I had adequate kitchen space.

Do you have any simple refrigerator or freezer hacks for saving energy or reducing food loss?