| Summer Air conditioning system | Winter Air conditioning system |
| Used in summer, when air is to be cooled. | Used in winter, when air is to be heated. |
| Refrigerating circuit (cooling coil) is used. | Refrigerating circuit need not be used. |
| Cooling of air may be accompanied by either dehumidification or humidification. | Heating of air is accompanied by humidification. |
| Water eliminator is not required. | Water eliminator is required. |
| One heating coil is used to control the temperature of air as per comfort level. | Two heating coils are used to control the temperature of air as per comfort level. |
| Low operating cost. | High operating cost. |
| Used in hot regions like INDIA, Gulf, Australia, Africa. | Used in cool regions like Europe, Russia, Japan etc. |