But before you can decide whether or not it makes sense for you to upgrade, you need to know exactly how much you stand to save every month by upgrading. And that will vary considerably depending on several particulars of your situation.
For instance, you will have to take the age of your current system into account. No matter how energy efficient your system was when you first bought it, that energy efficiency has almost certainly deteriorated over time. Plus, the older your system is, the less energy efficient it probably was to start with. And the less energy efficient your current system is, the more you will save when you upgrade to a newer, more energy efficient system.
But that is not the only variable you will have to be on top of. The amount you will save monthly and annually will also have to do with how much you use your HVAC system. If you live in a rather temperate climate, you may use your HVAC much less, both in the summer and the winter.
In a case like this, the percentage you will save with an equipment upgrade will be the same as it would for someone who lived in an area with a harsher climate, but the actual dollar value will be much lower. All that really means is that it will take you longer to recoup your investment, but it may still be worth it to invest in a new system now.