Mini Split vs Central Air: 7 Key Metrics Compared

Central air systems are the traditional HVAC systems found in many homes. Nowadays, mini splits are emerging not just as an add-on HVAC solution, but also as an alternative whole-house HVAC system. Mini split vs central air, which one should you use?

In this post, we’ll compare 7 key metrics and 1 bonus metric to see whether a mini split system would be the better choice, or the traditional central air can still hold its place. Below is a comparison table for quick glance:

Both systems are viable depending on your needs. In the following, we’ll discuss different scenarios, the pros and cons for you to decide which system is the best fit.

Mini Split vs Central Air Cost

Based on multiple sources, including my own clients, Home Guide and Fixr, below is a quick cost comparison between a mini split system (ductless multi-zone) and a central air system at different sizes.

These figures reflect the full system purchase + installation, including outdoor condensing unit, indoor evaporator and labor. Both systems assume no additional ductwork; mini splits are ductless and central air uses the existing duct in the house.

Use the above as a reference with caution because the cost of a full system installation varies greatly based on location, contractors, complexity and equipment/material brands.

Currently, the upfront cost of an equivalent mini split system is about 20-30% higher than a central air system when both systems are professionally installed (done by a licensed contractor).

However, mini splits offer an alternative low-cost solution, which is DIY installation.

If you buy a multi-zone mini split system with generally good reviews on Amazon, like the Senville SENA 28000 BTU Tri-Zone system, it costs about $3000. With two of this system, you get six head units and two outdoor units. If we include the cost of new tools for DIY installation and extra accessories, the total cost for this 4.5-ton system is roughly $6500.

At this price point, it is comparable, if not cheaper, than the equivalent central air system. Additionally, you get to enjoy the benefits of a mini split system.

Mini Split vs Central Air Efficiency

Nowadays, the condensing unit of central air systems is as energy efficient as a multi-zone mini split system at a similar capacity. A typical 4-ton multi-zone mini split system (ductless) has an energy efficiency rating of about 20 SEER2. An equivalent central air condensing unit is about 17-18 SEER2.

High-efficiency condensing units can stretch their efficiency to 22 SEER2, but the cost is higher.

The equipment itself has similar efficiency, but what’s different is the system as a whole.

Traditional central air systems distribute air through ductwork that is often built into the house. The age of the house, alongside the ductwork, can be more than 20 years. Hence, duct leakages and dirt buildup within the ducts (which leads to more air resistance) are unavoidable.

Mini splits, on the other hand, are often ductless. As a system, their efficiency is much closer to their equipment rating. DOE also supports the fact that mini splits avoid energy losses associated with ductwork in central air systems.

However, if you choose to go with ducted mini splits, which is a viable option, the energy efficiency will be discounted, though ducted mini splits often use short, sectional ducts, which have less energy loss.

The energy efficiency rating of an equivalent ducted multi-zone system can drop from a ductless system at 18 SEER2 to merely 14 SEER2, making it almost the same as a standard 15 SEER2 central air condensing unit.

Mini Split vs Central Air Electric Bill

A mini split system with 5-6 head units allows you to turn off those that are not in use. For example, during the day, you only turn on 3 head units downstairs. At night, you switch off the downstairs units and turn on the upstairs units.

Over time, this control flexibility can reduce your electric bill by a noticeable amount.

In comparison, a central air system heats and cools the entire house, whether you need it or not. New central air systems can practically implement zoning to save energy. However, it comes with additional costs as the setup needs motorized dampers, an additional thermostat and the right blower unit.

Modern central air condensing units are equipped with inverter technology to achieve variable speed for their compressors. The same goes for mini splits.

Hence, getting a hot room down to 75°F will not cause a power spike or strain the system as mini split compressors slowly ramp up to speed and then fall back to a stable rate to maintain the desired room temperature.

Mini Split vs Central Air New Construction

New constructions are the best to adopt a whole-house mini split system, as old houses are designed for a central air system. There’s no ceiling and wall space allocated for mini splits, making old houses hard to use mini splits in some cases.

A whole-house mini split system requires new houses to allocate spaces for the indoor head units. During the design stage, you can allocate ceiling space to put ducted mini splits or ceiling cassette units, if that’s your preference.

If you go for the wall-mounted units, the interior can be designed to blend those wall units seamlessly, which is an aesthetic problem for many old houses attempting to use a wall-mounted mini split, as they struggle to find a good location for it.

Additional rooms extended from existing houses can also tap into the benefits of mini split systems. Single-zone mini split systems are much more energy efficient than multi-zone systems. The most efficient mini split has a whopping 33.1 SEER2, outperforming any HVAC system on the market.

A whole-house duct system is costly. New constructions can save costs by going ductless with mini split systems. Either multiple single-zone systems for maximum energy efficiency or one multi-zone system for simplicity.

Mini Split vs Central Air Heat Pump

Mini splits, by default, are heat pumps. They can heat in cold seasons and cool in hot seasons. Most of the mini splits sold on the market come with a heat mode and a cool mode, though there are certain models for cooling only.

Similarly, many central air condensing units are heat pumps now. They are intended to replace the traditional gas boiler and furnaces for heating in regions that are not extremely cold.

There is a branch of mini splits that are designed for extreme weather. They are known as low ambient mini splits or “hyper-heating” mini splits.

Basically, these mini splits are designed to work under very cold outdoor temperatures. A typical mini split can operate down to 5°F, a low ambient model can still provide heating at -13°F, and the best mini split for heating can even work at -22°F.

The operating range of central air heat pumps is similar, but most of them are not as extreme as some of the mini splits. The range is usually -10°,F which is more than enough for most places.

In certain regions, it is a good idea to implement a backup heater. This is where a central air system is preferred over a mini split system because a gas furnace can be integrated into the same blower unit and switching between them is easy.

Whereas for mini splits, the backup heater is often baseboard or other forms of electric heaters, making the operating cost higher whenever the backup heater is used.

Mini Split vs Central Air Home Value

Whether or not a mini split system adds value to your home depends on the view of the buyers. However, in my opinion, a well-designed mini split system is as valuable, if not more valuable, than a central air system.

The trend of using a mini split to heat and cool a whole house is going upward. More and more people will see the benefits of it and accept it. Later, home buyers may even prefer houses that use mini splits.

I have many clients approach me for a whole-house mini split design service. Some of them are homeowners and some are contractors.

While I also have clients requesting central air design, it is mostly about independent reviews and comments because the design is already done by an experienced contractor.

Meanwhile, there are currently not many contractors who are experienced in various mini split designs. For example, mix and match different head units, ducted mini split design, integrated fresh air intakes and more.

A poorly designed mini split system may be seen as a burden rather than a bonus. Though the same goes for houses with a poorly-maintained central air system.

Mini Split vs Central Air Maintenance

Mini split systems have more items for regular maintenance than central air systems. With 4-6 head units, you may need to wash 8-12 filters every 2-3 months and chemically clean 4-6 evaporator coils every year, depending on the air quality in your area.

Whereas a central air blow unit only has 2-4 filters. The service interval is the same, unless you use a high MERV filter, which may require more frequent cleaning or outright replacement.

Having multiple mini split systems also means you have more items to take care of. However, on the positive side, it also means you have redundancy. If one of the systems fails, you still have heating/cooling available in certain parts of your house (perhaps, a backup heater is not needed then?).

With that said, mini splits are still new compared to central air systems. Service technicians may not carry as many spare parts as they foresee to fix your mini splits within an acceptable time frame, though there are technicians specialized in mini splits who can do so.

Technicians are also less trained and experienced on mini splits than central air systems. Thus, their response, troubleshooting and repair time may be longer than you might expect.

When the system is aged, ductwork needs to be cleaned and repaired. This goes both ways; ducted mini splits and central air systems. If you use ductless mini splits, then this is a non-existent cost.

Indoor Air Quality (Bonus)

Central air systems can be, and often are, equipped with a better filtration system than mini splits. Most of the mini splits use a basic plastic mesh filter to trap dust. Higher-end models may use carbon filters and other forms of media filters to improve their air filtration grade.

However, due to smaller scales, the filtration capability of mini splits is limited.

A central air blower unit can easily fit a high MERV filter to improve indoor air quality. High MERV filters have higher air resistances. Hence, the static pressure of the blower unit can be adjusted to match the system pressure.

Meanwhile, ducted mini splits have limited fan static pressure. Manufacturers usually don’t encourage you to simply change their filter type, as the static pressure may not be enough to deliver the required airflow, unless you have room to spare.

In the case where you need to upgrade your blower fan and motor to accommodate a higher-grade filter system, you can do so, as many central air blowers are customizable. There are a few available models to fit your system.

Whereas mini splits are standardized. You can hardly change any of the components other than the original brand/model (spare parts are also less flexible). Hence, it is much more difficult for mini splits to achieve the level of air filtration that central air systems provide.