Thanks for using Apple Support Communities. Using and maintaining your Apple MagSafe Adapter The Magsafe connector on your Magsafe Power Adapter might vary based on your computer, and the AC cord and AC plug style might vary based on your country or region. This is in addition to rights provided by consumer law. We offer this whenever you get service from us or from an Apple Authorized Service Provider. Also avoid prolonged contact between yourself and the adapter brick when the adapter is in use. We guarantee our service, including replacement parts, for 90 days or the remaining term of your Apple warranty or AppleCare plan coverage, whichever is longer. Avoid thick carpet, bedding, or furniture that would impact airflow on the adapter, as those items might trap heat radiated from the adapter case. If you’re using the AC power cord, place the MagSafe Power Adapter on a desk, table, or on the floor in a well-ventilated location. Plug the MagSafe Power Adapter directly into a power outlet or surge protector using the AC Plug, and make sure that air can flow around the adapter. To reduce the possibility of overheating the power adapter or of heat-related injuries, do one of the following:

The MagSafe and MagSafe 2 Power Adapters comply with the user-accessible surface temperature limits defined by the International Standard for Safety of Information Technology Equipment (IC 60950-1). The power adapter might become very warm during normal use. Temperature and the MagSafe Power Adapter

Our support article has this information: I understand that you're concerned about the temperature of your MacBook Air charger, and I'm happy to help.

Mac charger replacement policy