1. Earth-friendly fires
Use the right-sized burner!! When placing a small pot on a large element then a lot of heat and energy is wasted. So take an extra second and look the for the element that matches the size of the pot... Its a very easy thing that can save tons of energy yearly. Also, for boling water, an electric kettle is much more quicker and efficient as a pot on the stove according to Kate Heyhoe, author of Cooking Green: Reducing Your Carbon Footprint in the Kitchen.
2. Microwave it!
Microwaves are magic when it comes to eco cooking! Did you know that they use 80% less energy then usual ovens. This makes a green way of warming up leftovers or just any food that needs heating! An extra tip is to place the plate (or the food) on the outer edges of the microwave.
3. Buying refrigerators
The refrigerator is the most energy consuming household appliance, Therefore, just to try to lower it's energy use, skip the automatic ice-makers and water dispensers, which increase your unit’s energy use by about 10%. Water is easily available from the tap (if you live in Sweden, here it's perfectly fine drinking tap water) and ice you can make yourself in the freezer.