When considering whether heating or cooling is more energy-efficient, the answer is not as clear cut as you may think.
You might think that the temperature in your area might be the deciding factor, but that is not so. A recent study compared Minneapolis (one of the coldest areas in the USA) with Miami (one of the hottest. While it found that Minneapolis is about 3.5 times as energy-demanding as Miami, it still demonstrated that cooling is far more energy-efficient than heating.
If you compare an air conditioner with an electric forced air furnace or similar air resistance heat, it becomes clear that the air conditioning is far more efficient at moving heat energy. It is always good fun to ask someone in a hot climate if they spend more on heating or cooling their house. They almost always say they live in a hot climate so spend more on cooling the temperature.
The fact is, whether you live in an old inefficient home or a high-performance home, and whatever the temperature outside is, you are far more likely to spend more on heating than cooling, sometimes a lot more. It means that cooling is more energy efficient.