Determining which type of system is better for your home.
Whether you’re deciding on an HVAC solution for a new build, or weighing the options for updating your existing system, there are two basic types to consider – ductless mini-split systems and whole home or central air conditioning systems.
Though there are distinct differences between the two, with proper application and unit sizing, both mini-split and central air conditioning systems are efficient, cost-effective solutions.
Learning more about the capabilities, the differences and the requirements of each will help you determine which is right for your space and get you on the road to perfect air.
Understanding Mini-Split Systems
A mini-split, also known as a ductless system, is a compact HVAC system that can efficiently heat and cool small spaces, apartments, and other areas where ductwork isn’t practical or feasible. Like standard heat pump-based systems, a mini-split consists of two primary components: an outdoor compressor/condenser unit and one or more indoor air handlers.
Because of their size and relative simplicity, mini-splits are ideal for use in new additions to a home and as a solution for smaller spaces like offices or out building. They are also commonly used in apartment complexes and hotels where multiple small spaces require individual temperature controls.
How Does a Mini-Split Work
The outdoor condenser unit and the indoor air handler are connected by two small refrigerant pipes and the necessary power and communication wiring – all routed through a single 3-inch hole in the outer wall. This direct connection allows the units to constantly share information on indoor and outdoor conditions, boosting efficiency and allowing the system to optimize its performance based on your settings.
Those settings are handled by the mini-split’s third component – a controller in the form of a remote control or a wall-mounted thermostat. Just like a conventional system, this controller allows you to adjust the temperature, fan speed, timer, and other settings from a distance. Depending on the specific mini-split model, you may also be able to control your mini-split using voice commands or over Wi-Fi through a mobile app.
Operation Modes and Settings
When in cooling mode, a mini-split system reduces the indoor temperature by extracting heat from the indoor air and transferring it outdoors. When the thermostat is lowered, the refrigerant in the indoor unit’s evaporator coil begins absorbing heat causing it to evaporate, resulting in condensation on the coil. The air handler’s fan blows air over the coil, cooling it and distributing into the space.
For heating, the mini-split system operates in reverse. The system extracts heat from the outdoor air and transfers it indoors. The outdoor unit's compressor pressurizes the refrigerant, causing it to release heat, warming the indoor coil. The indoor unit's fan blows air over the heated coil, distributing warm air throughout the room.
Basically, a mini-split performs all the same functions of a conventional whole-home system on a much smaller scale – all without the need for duct work or complicated installation.
Different Types of Mini-Splits
While from a functionality perspective, all mini-split systems are basically the same, there are configuration options that make the mini-split a flexible choice. There are 3 configuration technologies that go into to “designing” a system that meets a buyer’s specific needs.
Single-zone vs. multi-zone mini-splits
Mini-splits can be installed in two main configurations: single-zone and multi-zone. Single-zone mini-splits are designed to cool or heat a single room or area while multi-zone mini-splits have the capability to cool or heat multiple rooms or areas simultaneously, using a single outdoor unit and multiple indoor units.
Ducted vs. ductless mini-splits
Though one of the primary benefits of a mini-split system is that it can be installed without the need for ductwork, simplifying installation and maximizing energy efficiency, mini-splits can also be installed using ductwork. This application is ideal for homes or buildings that have existing ductwork.
Wall-mounted vs. ceiling cassette mini-splits
Another aspect to consider when choosing a mini-split system is the installation style. Wall-mounted mini-splits are the most common type and are installed high on the wall for efficient air distribution. Ceiling cassette mini-splits are installed in the ceiling and distribute air downward, conserving wall space and offering a more discreet appearance.
Benefits of a Mini-Split System
With the right application, mini-splits have some obvious benefits.
Flexibility and Ease of Installation
Along with a variety of configuration options, ductless mini-splits can be easily installed in older homes, small apartments, additions, or areas with limited space. For new construction, installing a mini-split can be as simple as cutting a single hole in the wall where the system will live, reducing installation cost associated with ductwork and other infrastructure.
Efficiency and Cost-Savings
With efficiency ratings of up to 28.1 SEER2 and 11.9 HSPF2, Lennox mini-split systems deliver cost-savings along with convenient comfort – and may even make you eligible for incentives and rebates. Installed properly, the addition of a mini-split system can help cut your energy bills by hundreds of dollars a year.
Improved Indoor Air Quality
Lennox mini-split systems feature advanced filtration technology that helps improve indoor air quality. The filters trap and remove dust, pollen, allergens, and other airborne particles, creating a healthier more comfortable living or working environment.
Multi-Zone Comfort
One high-efficiency outdoor unit can support up to five indoor units or comfort zones, offering you a customizable and energy-efficient whole-home heating and cooling solution.
Minimum Noise
Built-in features and technologies keep noise to a minimum. Indoor units operate as low as 20 dB which means they are literally whisper quiet. Our outdoor units operate as low as 53 dB – roughly the sound of an electric toothbrush.
The Downsides of a Mini-Split
Despite their benefits, there are some drawbacks to choosing a mini-split vs. a conventional central system.
Limited capacity
Most mini-split systems are designed to cool or heat specific areas rather than the entire home. If you have a large space or multiple rooms that require cooling or heating, you may need to install multiple units, which can increase the overall cost.
You can learn even more about mini-split systems at our mini-splits glossary page, or explore our selection of energy efficient mini-splits here.
Understanding Central Air Conditioning
A central air conditioning system (or central A/C) is a system in which air is cooled at a central location and distributed to and from rooms by one or more fans and ductwork.
Similar to a mini-split, a central A/C system consists of an outdoor unit and an indoor unit – but that’s where the similarities end. The outdoor component if a central A/C system can be a traditional air conditioner or a heat pump. This unit works together with an indoor furnace or air handler, usually located in an attic or basement, to condition and distribute air throughout the home from a central location.
How Does a Central Air Conditioner Work
Though on a larger scale, an air conditioner-equipped central A/C system works in much the same way as a mini-split in cooling mode. The systems uses a coolant (or refrigerant) cycle to remove heat from the indoor air and release it outdoors.
During the A/C cooling cycle, cold liquid refrigerant is sent from the outdoor condenser to the indoor evaporator by way of coolant lines where the coolant causes condensation to build up on the evaporator coil. Fans within the furnace or air handler circulate the indoor air over the condensation, cooling it and sending it through the ducts cooling the home.
As the coolant warms within the evaporator coil, it expands into gaseous form. The now gaseous refrigerant is then returned to the outdoor unit where it is condensed back to liquid form and its stored heat is released.
System Options
Central air conditioning systems can be equipped one of three types of primary equipment: air conditioners, heat pumps, and packaged systems.
While air conditioners and heat pumps utilize much of the same infrastructure including ductwork, electrical and refrigerant conduits, an air conditioner is only capable of cooling a home. Heat pumps, much like mini-split heat pump systems, also have the capability of reversing that cycle to deliver heat during cold weather. Unless you live in a climate with extremely mild winters, a central A/C system equipped with an air conditioner must be paired with a gas furnace or other heat source in order to deliver year-round comfort.
In a packaged central air conditioner, the evaporator, condenser, and compressor are all located in one cabinet. Packaged units eliminate the need for a separate, indoor furnace. Ductwork usually runs directly to and from the unit which is typically installed outdoors.
Benefits of Central Air Conditioning
Because most homes today are built with central A/C, that gives homeowners the built-in advantage of having ductwork and infrastructure already in place for central A/C applications. In addition to that, central HVAC systems offer:
Ease and Cost of Installation
Though mini-split systems require far less work, equipment, and structural modification to install into a new build, replacing a central air conditioner in a home with existing ductwork and electrical infrastructure is less labor intensive. Installation can be as simple as disconnecting the old air conditioner unit, reconnecting the new one, and performing the necessary start-up tests providing the other components of the system are compatible.
Efficiency and Cost-Savings
With efficiency ratings of up to 25.80 SEER2, Lennox central A/C systems can lower your energy bill, while still keeping your home cool and quiet. It may even help you qualify for incentives and rebates.
Convenience and Comfort
Having control over your whole home from one convenient thermostat is extremely convenient. If you opt for an integrated zoning system, each control panel allows easy access to area-specific control.
Improved Indoor Air Quality
Central air conditioning systems offer a variety of filtration add-ons and modifications. The ductwork within the system provides opportunities to install additional filtration equipment such as HEPA filters, UV lights, and high-performance filter boxes. You can visit our Indoor Air Quality page to learn more about high-quality options Lennox offers.
The Downsides of Central Air
There are a few drawbacks to central air systems, especially when installing a complete system.
Cost of Ductwork and Infrastructure
Installing a central A/C system into a new build or adapting a non-ducted home or add-on can be costly. If your space isn’t pre-ducted, be sure to take the additional labor and equipment into account when comparing.
Energy Efficiency
Though efficiencies among central A/C units have climbed in recent years, reaching as high as 25.8 SEER2 with high efficiency units, the simplicity of a mini-split system makes them more efficient.
You can read more about central air systems here or explore and compare Lennox’ central air options here: air conditioners and heat pumps.
Factors to Consider When Choosing
Now that you understand a bit about both systems and know many of their pros and cons, you can better weigh them against one another to determine which is right for your space.
The Size and Layout of Your Space
Beyond simply comparing the two, and probably the most important thing to take into account, is the space you’ll be cooling (and heating). The size and layout of the space play a primary role in determining how effective and efficient your system will be once it’s installed.
Here are three important questions to answer before choosing –
- How large is the space?
- How many rooms or zones are within the space?
- Is there existing ductwork or infrastructure?
With these questions answered, you should be able to get a basic idea of which options would be best for you.
Once you feel you have a good idea of which type of system is right, we encourage you to find a qualified HVAC professional to help you make a final decision. Though we’ve covered a lot of ground that will help you make an educated decision, there may be details or nuances of your space that a trained technician will help you better identify – that may end up steering you in a better, more beneficial direction.
Find a local Lennox dealer of technician today to make sure you choose the best system for your home.
