To help you understand a bit more just exactly how vaporizers work, you will want to think about a few things. When you are cooking and you need to heat up a pot of water to boil something you are actually working with molecules. When you heat up the water, the water molecules escape and the liquid becomes a vapor. If you decided to leave the water in the pot and not turn the burner on, the water will still evaporate, but at a much slower rate than when you apply heat to it by turning the burner on. Once the water becomes hot it evaporates and when it reaches the state of boiling it evaporates even faster.
Another way to see how vaporization occurs is by going into your bathroom and pulling out your hairdryer and doing a little experiment. Go ahead and shampoo your hair and then get your dryer out and begin to dry your hair. Your hair is going to dry faster by using the hair dryer than if you left your hair to dry naturally of course. This is because the heat from the hairdryer is evaporating the water in your hair. When you leave your hair to dry naturally, the air around you is simply not hot enough to evaporate the water in your hair quickly.
Your personal vaporizer device works with this same way. As you probably have already experienced herbs will release their natural oils into the air if they are just left to sit in a room for perhaps aromatherapy purposes, but if you apply heat to the herbs, the release of their natural oils will happen much more quickly.
If you are using a vaporizer as an alternative to smoking tobacco, you will be doing yourself a favor because by inhaling the vapors instead of smoking tobacco, you are helping your lungs to heal and not be further harmed.