Which needs more energy heating or cooling?

Question

In order to change the temperature of 1 gram of water

Answer 1

If the processes to heat or cool were 100% efficient then the energy requirements would be identical. However, at the current time most methods for generating heat are much more efficient than those used to cool. So in general it takes more energy to cool.

WK

Answer 2

The amount of energy needed is defined by this equation.

Q = mass * specific heat of the material * temperature difference

or in typical SI units

[J] = kg * [J / (kg * °C)] * °C [=] J

The sign (+/-) refer to the addition removal of heat. To answer the question from a complete academic viewpoint, it'll depend on water's heat capacity over the range of temperatures. Most substances have a temperature dependent specific heat (usually negilble over small temp ranges but its still present).

Thermodynamic is all state equation based. It doesn't matter how you go from point A to point B. Therefore, point a -> b is the same as b -> a energy wise unless there is some underlying dependence present (like the Cp of the system).

From a mechanical stand point, it all depends on the efficiency of the method (cooling or heating). In an ideal case where you have the same efficiency, no exterior heat loss, no phase changes, closed system, etc; I'd assume it would take the same amount of energy.

Answer 3

Depends on how you heat and cool.
You can heat by using a heat pump (A/C unit that can pump heat either way). That uses less electricity than if you used heaters (resistance heating) for the same amount of heat.
Also when cooling, the efficiency varies greatly depending on the temperature of (the outside) where you are getting rid of the heat to.
That's why some systems use underground water to dump the heat into, as it is cooler than the outside air. Result, lower energy requirements for the same amount of cooling.

Answer 4

On a "per degree" basis, it is more difficult to cool than to heat. Here is why:

In order to heat a quantity of space 10 degrees, you simply generate heat by applying current to a coil or with a flame to warm a metal, then blow air through the grid. You get warm air and you're well on your way to a toasty winter's evening watching TV.

But to cool the same quantity of space 10 degrees, you have to compress a gas, then cool the compressed gas with heat sinks and ambient air. Then you have to let the gas expand inside a radiator and then you can blow air across the now cold radiator. Then you can sit back and watch TV while complaining about all the water running out of you air conditioner.

The point is, that the mechanism to artificially cool air is more complex than to heat it.

Answer 5

Think about it.

In most instances, if you refering to the average home, it takes more energy to heat. It is a simple matter of the amount of temperature differential. Even on a 110 degree day, you only have to remove 40 degrees to be comfortable. And at night, it's often cooler and you need to remove even less degrees.
However, on the other end of the thermometer, when it's zero degrees out, you have to add 70 degrees to be confortable, and at night, there's no reprieve - it just gets even colder.

Answer 6

Naturally, it would take more energy to cool something, as when a substance cools, the resistance becomes more through time, whereas with heat, the resistance lessens through time.

Answer 7

The energy used is probably the same, but the METHOD you use
will vary considerably, (more energy to cool)

Answer 8

both need energy [if the something you want to heat is cold you need high energyto heat it,also if you want to col
something and it is heat you need energy to col it,so it depend on the temp of the something you want to heat or to col

Answer 9

In Alaska, heating.
In Texas, cooling.

Answer 10

cooling