A well-located air-conditioner makes you feel happy which is not only important for your body health but also your psychology. High temperature is dangerous for people who have heart and respiration problems. Especially old people should have air-conditioners. Being spread negative and positive ions clears some bacteria, viruses and mites which cause some health problems. Unfortunately, many people smoke at home and air-conditioners are ideal devices for odours. Fresh air that you feel in the countryside or a picnic/camp site is because of negative ions in the air. Modern air-conditioners release extra negative ions to the air and make you feel better.