There is nothing more relieving and calming than walking into an air-conditioned room at the end of a sweltering day. Indeed, it’s hard to conceptualize a time before those miraculous inventions cooled the insides of our homes in the worst of the summer. About two-thirds of all homes in the U.S. have air conditioners, and understandably so.

Every year, U.S. homeowners spend more than $11 billion on their air conditioners — both in buying new and in maintaining the old. This is an important distinction. Since air conditioners can be expensive, it is better to maintain the existing one and help it do its job of keeping you cool. While it is true that doing something like switching to high-efficiency air conditioners and taking other actions to keep your home cool could reduce energy use for air conditioning by 20% to 50%, it is still good to develop positive care habits for your cooling system. Check out this checklist of maintenance tasks that are advisable for maintaining your air conditioning system.

1. Clean the Filters
When your air conditioner is in constant use, pollen, dust, and other debris clog the unit’s filter, making it work double time to deliver you fresh, cool air. It is also important to replace these filters periodically, because no matter how often you clean them, they are likely to wear out over time and cause you and your family allergies.

2. Clean the Coils
Before the summer begins, you need to clean your air conditioner coils. The dirtier the coils, the more likely they are to absorb heat over time, which will surely increase your utility bill. Also, the more dust the air conditioner coils collect, the worse for the machine in general.

3. Seal the Windows
Sealing the windows around an air conditioner not only helps lower your utility bill, it also keeps your home healthier and helps the unit last longer by reducing the erosive effect that weather and friction could have had on it.

Make sure to call an HVAC service to help you install and inspect both your cooling systems in the summer and for heating services in the winter.