In many areas, having an air conditioning unit is a must, particularly during the hot summer months. But they don’t last forever, and if you want your unit to keep you cool all summer long, you need to know when to replace it.

But how, exactly, do you know when it’s time to get rid of your existing AC and trade it in for a newer model?

A recent video from realtor.com outlined surefire signs that you need to replace your air conditioner unit, including:

• It’s been 15 years since you purchased it. Most conventional air conditioners are designed to last anywhere between 12 and 15 years. If you’re getting close to that upper limit, it’s probably time to replace your AC with a newer model.
• You’re spending a ton on repairs. Often, AC units can be repaired quickly and affordably. But if you find you’re spending a ton to repair an existing AC unit, it might make more sense to just invest in a new one. A good rule of thumb is that if repair costs equal more than 50 percent of the cost of a brand new unit, you should opt out of repairs and buy a new one instead.
• Your energy bills are going up. New air conditioners are designed to be energy efficient. If you have an older unit, your air conditioner may be using more energy than it needs to, causing your energy bills to creep up in the process. If you’re concerned your AC is increasing your energy costs, consider buying a new, more energy-efficient unit.