Years ago, air conditioning was something of a luxury in many homes. As a result, countless homes out there lack ductwork because they don’t have forced-air heat or air conditioning. For those homes, adding air conditioning wasn’t an easy thing to do. For the most part, homeowners in that situation only had two choices. They could tear apart their finished walls to add ductwork for a central air conditioning system or opt for individual window-mounted units. Today, however, mini-split systems offer a new option for homes without ductwork. Here’s how their efficiency compares to central air conditioning systems and some of the other things you should consider when comparing the available options.

Understanding AC System Efficiency

Since energy efficiency is a big concern for homeowners purchasing air conditioners, all new units come with efficiency ratings. In the United States, the rating system for AC efficiency is the seasonal energy efficiency ratio or SEER. The rating comes in the form of a number that you can use to gauge the relative efficiency of one unit versus another.

SEER ratings represent the total amount of cooling output an AC produces during an average cooling season, divided by the electricity used to power it. An AC unit’s SEER rating represents its maximum efficiency while operating under optimal conditions. In the real world, the unit’s efficiency may vary depending on things like outdoor temperature, the size and layout of the rooms it’s cooling, and the manner of its installation.

The bottom line, however, is that the higher the numerical SEER rating, the more efficient the AC unit. Knowing that, it’s possible to compare the efficiency of today’s mini-split AC systems to that of comparable central AC systems. Here’s what you need to know about the SEER ratings you might expect on the average central air conditioner and comparable mini-split systems.

Average Central Air SEER Ratings

For a long time, central air conditioning systems remained the most efficient way to cool a home. The reason for that is simple. Compared to window AC units, a central AC system can get cold air to the exact parts of the home that need it most. And window AC units allow energy leakage at the point of installation that central AC does not.

At the time of this writing, the average SEER rating for most central AC systems comes in between 13 and 21. In reality, however, the age of many existing central air conditioning systems means that plenty of still-used systems aren’t anywhere near that efficient.

It’s also worth noting that the US Department of Energy routinely increases the minimum acceptable SEER rating for sales of new central AC systems. In 2023, states in the northern half of the country can only purchase new AC systems with a SEER rating of at least 14. States in the southern half of the country must purchase systems with a SEER rating of at least 15.

Average Mini-Split SEER Ratings

Mini-split AC systems must meet the same minimum efficiency standards as central air conditioners. However, it’s hard to even find mini-split systems with a SEER rating below 20 these days. In some cases, mini-split SEER ratings may be as high as 33. That means they’re more efficient than comparable central air conditioning systems in almost every case.

The reasons for the added efficiency are manifold. The most important reason is that they minimize energy loss by not relying on ductwork to carry cooled air around a home. Ductwork routinely loses energy through poor insulation and air leakage. The losses aren’t trivial. According to the US Department of Energy, the lack of ductwork can make a mini-split system up to 30% more efficient than a central air system. When you consider that every bit of cooled air that never makes it into a room represents wasted operating costs, it’s quite obvious what a big advantage mini-split systems enjoy.

Another reason for the additional efficiency of mini-split systems is the fact that they create naturally zoned cooling systems. Since each cooled room has its own independently controlled air handler, homeowners can precisely control which rooms stay cool. By comparison, central air conditioning systems mostly feature simple on and off controls for the whole home, or at best, upstairs and downstairs zone control.

Additional Considerations

When comparing central air conditioning system efficiency to mini splits, there’s one important caveat to keep in mind. It’s that there are always examples of either type of system that would seem to go against the statements made above. For example, some of the higher-end central air systems on the market today feature variable-speed motors that can improve their efficiency significantly. There are also mini-split systems that sit at the bottom end of the allowable efficiency range.

Central air conditioning systems that employ the latest in efficiency technologies can have SEER ratings of up to 26, putting them easily on par with almost every mini-split system available today. It’s important to realize, though, that the extra efficiency comes at a cost. Such systems can cost thousands of dollars more than the average central AC system. That means the added efficiency won’t translate into net cost savings until years after installation.

Another thing to consider is whether a heat pump might be a better fit for your home than a conventional air conditioner. Heat pumps regularly outperform standard cooling systems and also add efficient heating capabilities to your home. Plus, they’re available as both central HVAC units and mini splits. Since it doesn’t get too cold in Norcross, GA, even in the middle of winter, heat pumps make an excellent addition to any home here.

The Bottom Line

The most important takeaway is that mini-split AC systems are quite efficient. Also, their average efficiency rating is higher than what you’d find on most comparable central air conditioning systems. For homes without preexisting ductwork, that makes mini-split systems an ideal choice. They’re easy to install and offer precise cooling control as well as significantly lower operating costs.

As always, though, the key to selecting the right cooling option for your home is to consult with an expert before making a purchase. Here in Norcross, you won’t find more knowledgeable HVAC experts than the team at Bardi Heating, Cooling & Plumbing. We’ve served the area since 1989 and offer a unique customer satisfaction guarantee that the competition can’t match. Plus, we’ve got a wealth of experience with all of the latest central air and mini-split systems.

We’ll also be the first to tell you that, depending on your home’s specific cooling needs, replacing an existing central air conditioning system with a mini split may not be worth the expense. The only way to know for sure is to let our trained technicians evaluate your home and report what they find. Once they do, you can make an informed choice, and we can install whichever system suits your home best.

So, if you’re in the market for a new air conditioning system, be it a central air or mini-split system, contact Bardi Heating, Cooling & Plumbing today so we can help you make the right decision. We provide heating, cooling, and plumbing services.

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