Yes, new AC units are more efficient than old ones. Case closed, right?
Not so fast!
While a new air conditioner will almost definitely be more efficient than the one you're thinking about replacing, it's important to understand why it's more efficient and what features you can look for to maximize AC efficiency.
Also: Different types of air conditioners are more efficient than others, so you'll want to know about the different kinds that are available.
Let's do a deep dive into air conditioner efficiency! We'll consider past efficiency standards vs. current ones, plus how AC features and AC types can improve (or detract from) the real-world efficiency of a given air conditioning unit.
Important Note: Energy efficient air conditioners are more affordable than ever! At the time of publication, Georgia homeowners can qualify for thousands of dollars in rebates for purchasing an energy efficient AC or heat pump!
Past efficiency standards for air conditioners
Prior to 1992, air conditioning units were super inefficient. It was in that year that the first meaningful heat pump and air conditioner efficiency standards went into effect: a Seasonal Energy Efficiency Rating (SEER) of 10 for residential central AC systems.
Have you heard of SEER before? It's the primary metric used to gauge an air conditioning system's efficiency. The higher the SEER, the higher the efficiency.
Nowadays, the U.S. Department of Energy uses SEER2 instead of SEER to measure air conditioner efficiency. It's a similar, if slightly more accurate, version of the original SEER metric.
If your home's air conditioner was installed prior to 2006, it might only be a 10 SEER system. As of 2025, there are still several around!
However, 2006 was the year an updated air conditioner efficiency standard went into effect. Starting then, all new ACs were required to have a minimum rating of 13 SEER.
Current efficiency standards for air conditioners
At the time of publication, the current efficiency standard for residential air conditioning units is the one that went into effect in 2023. It just so happens that 2023 was also the year that SEER2 supplanted SEER as the primary metric for gauging AC efficiency.
Currently, air conditioners sold and installed in our climate zone, the Southeastern United States, must be rated at 14.3 SEER2 (equivalent to 15-16 SEER) or higher.
So if you've got an old air conditioner that was installed prior to 2023, there's a good chance it's only a 13 SEER system. For you, a new air conditioner that meets the minimum federal efficiency standard will be more efficient than your old one.
Heck, you might even have a pre-2006 air conditioner rated at just 10 SEER! Whatever you replace it with will be significantly more efficient, even if you get the lowest-SEER model!
Plus, there's more to AC efficiency than just SEER nowadays. Lots more.
Features that make new AC units more efficient
The thing about SEER and SEER2 is that they're just one part of the picture when it comes to efficiency.
There's another thing that really separates the most efficient, highest performing air conditioners from the rest: the type of compressor.
Modern air conditioners are available with three different types of compressors:
- Single stage: This is what you get with a standard air conditioner. There's just one stage of cooling, so the AC will always be running at max after it turns on. Your current AC is probably like this. Most single stage air conditioners are rated at 14.3 to 16.5 SEER2.
- Two stage: These are somewhat more efficient than single stage air conditioners. There are two cooling stages: high and low. Most of the time, the AC will run for longer cycles in the lower stage. When it's really hot outside or when you need more cooling capacity, it will switch to the higher stage. It uses less energy to run an AC in the lower stage, which is why two stage units are more efficient. These tend to be rated between 16 and 19 SEER2.
- Variable speed: This type of compressor is vastly more efficient than single or two stage models. As the name suggests, this type of air conditioner varies its cooling capacity and fan speed to match your precise cooling needs. The result is that it uses less energy, costs less to operate, provides better humidity control, and makes your home more comfortable compared to other models. SEER2 for these systems typically ranges from around 16 to over 21.
So, all else being equal, a 16.5 SEER2 system with a two stage compressor will be more efficient than a 16.5 SEER2 system with a single stage compressor. This is why we say that SEER and SEER2 aren't the only AC efficiency metrics worth knowing about!
The most efficient types of air conditioners
While a variable speed 21 SEER2 air conditioner is one of the most efficient options available when it comes to ducted central systems, there's an even more efficient type of AC you might consider: a ductless mini-split air conditioner.
These air conditioners, most of which are actually heat pumps that can cool and heat your home, are typically used for:
- Home additions such as adding a sunroom, home office, or bedroom
- Detached buildings like workshops or garages
- Supplemental cooling for hot upstairs rooms
They typically are not used to provide air conditioning to your entire home, although you technically could outfit your home with them… if you wanted to.
Ductless mini-split systems consist of an outdoor condenser unit and an indoor unit. That probably sounds like a central system, but the difference is that the indoor unit is installed inside your living space-not in a crawlspace or attic.
This being the case, no ducts are needed! This is one reason ductless mini-splits are so efficient. There's no energy lost through ductwork because there isn't any ductwork at all.
It also helps that ductless mini-splits use variable speed compressors!
Ductless mini-split systems range from 20 to 35 SEER2. That's super efficient.
Conclusion: New AC units are definitely more efficient than old ones
With higher SEER and SEER2 efficiency standards and modern, efficient compressors, new air conditioning units are vastly more efficient than what you're probably used to.
Even if you go with the least expensive, least efficient model, you will still pay less to cool your home in the summer!
If you live in Metro Atlanta and have questions about replacing your air conditioner with a more efficient AC unit, PV Heating, Cooling & Plumbing can help! We're also an approved contractor for Georgia's energy rebate programs, so we can help you save thousands on your next energy efficient air conditioner!
Call us today at (404) 798-9672 or schedule an appointment online!
