Among the major culprits here are inefficient appliances. According to the United States Department of Energy, a gas burner delivers only 35 to 40 percent of its heat energy to the pan; a standard electrical element conveys about 70 percent. Anyone thinking about kitchen renovation should know that induction cooktops, which generate heat directly within the pan itself, are around 90 percent efficient. They can out-cook big-B.T.U. gas burners, work faster, don’t heat up the whole kitchen, and are becoming more common in restaurant kitchens.

Maximizing the transfer of heat from burner to pot produces better food. In deep frying, the faster the burner can bring the oil temperature back up after the food is added, the quicker the food cooks and the less oil it absorbs. In boiling green vegetables, a fast recovery time means better retention of vibrant color and vitamins.

No matter how efficient an appliance is, the cook can help simply by covering pots and pans with their lids. Some of the heat that enters through the bottom of the pot exits through the top, but a lid prevents much of it from escaping into the air. This is especially true when you’re bringing a pot of water to the boil. With the lid on, it will start bubbling in as little as half the time. Turning water into steam takes a lot of energy, and every molecule that flies away from the water surface takes all that energy with it into the air. Prevent its escape, and the energy stays with the pot to heat the rest of the water.

Once a liquid starts to boil and is turning to steam throughout the pot  the bubbles of a boil are bubbles of water vapor  nearly all the energy from the burner is going into steam production. The temperature of the water itself remains steady at the boiling point, no matter how high the flame is underneath it. So turn the burner down. A gentle boil is just as hot as a furious one.

Cooking doesn’t get much more straightforward than boiling and steaming vegetables, grains, and the like. But sometimes it takes forever, which either delays dinner or results in crunchy beans and diners suffering for it later. And you can’t speed the process by raising the heat.

In fact it’s easy to save loads of time and energy and potential discomfort with grains, dry beans and lentils, and even pasta. But it requires a little thinking ahead. It turns out that the most time-consuming part of the process is not the movement of boiling heat to the center of each small bean or noodle, which takes only a few minutes, but the movement of moisture, which can take hours. Grains and dry legumes therefore cook much faster if they have been soaked. However heretical it may sound to soak dried pasta, doing so can cut its cooking time by two-thirds  and eliminates the problem of dry noodles getting stuck to each other as they slide into the pot.

The trickiest foods to heat just right are meats and fish. The problem is that we want to heat the center of the piece to 130 or 140 degrees, but we often want a browned, tasty crust on the surface, and that requires 400 degrees.