Mini Split vs Central Air: Which Is Right for Your Home?

Pick a ductless mini split if your house has no ducts, or if you want to heat and cool a few rooms on their own settings. Pick central air if you already have ductwork in good shape and want every room cooled evenly from one thermostat. Both are split systems with an outdoor unit tied to indoor equipment by refrigerant lines, so the real difference is how the cooled air gets to your rooms.

How each system works

A central air conditioner shares the furnace's ducts and blower. The Department of Energy's Energy Renovations HVAC guide explains that refrigerant is piped from the outdoor unit to an evaporator coil in the indoor air handler, where it cools the air before the blower pushes it through the ducts. A central heat pump works the same way and also heats through those ducts.

A mini split skips the ducts. The same DOE guide describes one outdoor compressor unit connected to one or more wall- or ceiling-mounted indoor units, with the refrigerant tubing passing through a small hole in the wall. A single-zone system has one indoor head. A multi-zone system runs several heads from one outdoor unit, each serving its own room or area.

A heat pump mini split heats as well as cools. The DOE guide notes that cooling-only mini split air conditioners exist too. A central air conditioner only cools, and the guide says it is usually installed alongside a central furnace that handles the heat.

Efficiency ratings and the federal minimums

Three ratings matter here. SEER2 measures cooling efficiency over a season, EER2 measures cooling at a hot 95°F outdoor temperature, and HSPF2 measures heating efficiency over a season. Higher is better on all three.

Federal rules count both systems as central air conditioners or heat pumps when they are single-phase and rated below 65,000 Btu per hour. The definitions in 10 CFR 430.2 even name multi-head mini-split combinations. So one set of minimums covers both. Here is what 10 CFR 430.32 requires for split systems made since January 1, 2023:

The regulation's Southeast covers states such as Texas, Florida, Georgia and Virginia. The Southwest is Arizona, California, Nevada and New Mexico.

ENERGY STAR sets a higher bar. Its Version 6.2 specification asks for 15.2 SEER2 and 12.0 EER2 from a split air conditioner, and 15.2 SEER2, 11.0 EER2 and 7.8 HSPF2 from a split heat pump. For the cold climate label, the heat pump criteria page asks more of a ductless system (8.5 HSPF2) than a ducted one (8.1 HSPF2).

Both of our example models beat those minimums. Fujitsu lists its Airstage Altair 500 series at up to 26.0 SEER2 and 10.8 HSPF2. Carrier lists its Comfort 24SCA4 central air conditioner at up to 16 SEER2 and 13.5 EER2. "Up to" means the best pairing, so ask your installer for the rating of the exact combination they quote.

Ducts are the biggest difference

A rating tells you how efficient the equipment is. It does not tell you what your ducts lose on the way to the rooms. ENERGY STAR's duct sealing page says that in a typical house, about 20 to 30 percent of the air moving through the ducts is lost to leaks, holes and poor connections. Ducts in an attic, crawlspace or garage are one of the warning signs it lists.

The DOE's home cooling infographic puts duct air loss at about 30 percent of a cooling system's energy use.

That does not make central air the wrong choice. ENERGY STAR's fix is to seal the ducts and insulate the runs in attics, crawlspaces, basements and garages, which it says makes a home more comfortable and energy efficient. The same DOE infographic says central air gives the most even cooling throughout the home and can be cost-effective if you already have ducts. The DOE's HVAC guide puts ductless mini splits at about 30 percent more than central heat pumps, before counting any ductwork. That ratio comes from a 2010 DOE figure, so treat it as rough.

Zoning and comfort

With a mini split, zoning comes built in. Each indoor head has its own setting, so you can keep a home office cool and a spare room off. ENERGY STAR's ductless heating and cooling page names hot or cold spots, including rooms used as home offices, as a reason to consider one.

Central air usually runs from one thermostat. You can zone it, but that takes extra hardware. Carrier's HVAC zoning system page explains that motorized dampers inside the ductwork open and close to send air where it is needed, and its Infinity zoning panel controls up to eight zones. Carrier says many existing systems can be retrofitted.

Installation: ducts vs line sets

A central system needs a duct network, an indoor coil and an outdoor unit. Carrier's 24SCA4 installation instructions cover sizes from 1.5 to 5 nominal tons and ask for at least 6 inches of clearance on one side, 12 inches on the others and 48 inches above the unit. Refrigerant runs beyond 80 feet can cause what Carrier calls substantial capacity and performance losses. The installer also brazes the joints and evacuates the lines and indoor coil to 500 microns.

If the house has no ducts, the ducts are the hard part. The same DOE guide says that if you would need to install ducts to add central air, a ductless mini split heat pump may be the less expensive option up front.

A mini split needs a line set instead: copper refrigerant tubing, a drain hose and wiring between the two units. Daikin's wall-mounted installation manual shows a mounting plate on the wall and a through-the-wall hole of 2-9/16 or 3-1/8 inches, depending on the model. ENERGY STAR suggests routing the line set through closets, attics, basements, crawlspaces or garages to avoid patching walls.

Both makers want a professional to do the work. Daikin's manual says to always use a licensed installer or contractor, and Carrier's points owners to a qualified installer or service agency.

Heating

A heat pump mini split is a full heating system. ENERGY STAR says mini splits can heat and cool a whole home, and that its certification tests heat pumps for low-temperature performance down to 5°F. Fujitsu rates the Altair 500 to heat in outdoor temperatures down to 5°F. For even colder spells, ENERGY STAR suggests pairing a cold climate unit with a backup heat source.

A central air conditioner gives you no heat. You can get the same ducted layout as a heat pump instead. The DOE guide warns that ducts may need to be larger for a heat pump than for a gas furnace, so ask the installer to check them.

Noise, filtration and humidity

Noise is hard to compare from spec sheets. Fujitsu lists the Altair 500 at "as low as 19dB," without saying which unit that figure is for. Carrier lists the 24SCA4 outdoor unit at as low as 73 decibels. The two makers do not measure the same thing, so treat these as each maker's quietest claim, not a head-to-head test. Carrier's manual says to keep the outdoor unit away from windows, patios and decks.

Filtration works differently. A central system pulls the house's air back through one filter at the indoor unit, and Carrier's owner's manual warns that a clogged filter raises running costs and shortens the unit's life. A mini split filters the air of the room each head serves, through a washable filter in every head. Some add extras, such as the titanium apatite filter Daikin offers or the apple-catechin and ion deodorizing filters Fujitsu lists.

Both remove humidity while they cool. Carrier says its single-stage 24SCA4 offers standard humidity control and that a two-stage compressor gives more advanced control. Many mini splits add a Dry mode, Daikin's and Fujitsu's among them. Daikin's operation manual says Dry removes humidity while holding the room temperature as much as possible. Our guide to AC modes and remote symbols covers when to use it.

Maintenance and lifespan

Mini splits ask for more frequent, simpler care. Daikin's manual says to clean the air filters once every 2 weeks, and to clean the optional purifying filter every 6 months and replace it every 3 years. With a multi-zone system, that means every head.

Central systems ask for less from you and more from a technician. Carrier's owner's manual says the indoor coil needs minimal cleaning if you keep the filter clean. Its checklist leaves coil cleaning, drain cleaning and duct leak checks to a qualified technician. Carrier also asks for at least 12 inches between the outdoor unit and tall grass, vines or shrubs.

On lifespan, the makers' guidance overlaps. Trane says a central air conditioner lasts about 15 years in general, less where it runs long and hard, as in Florida or the desert Southwest. Lennox's air conditioner lifespan guide puts both central air and ductless mini splits at 15 to 20 years. Mitsubishi Electric says properly maintained ductless heat pumps have the same life cycle as traditional HVAC systems. ENERGY STAR's when to replace page suggests considering a new unit once a heat pump or air conditioner is more than 10 years old. If your mini split is a Mitsubishi and it flashes a code, our Mitsubishi mini split error codes list explains it.

Which one suits your house

An older house without ducts is the classic mini split job. ENERGY STAR names older homes heated by radiators or baseboards, plus additions and outbuildings where extending ducts is difficult. The DOE guide says a mini split air conditioner can also work where you want to keep a non-ducted heating system.

A house with good ducts usually points to central air or a ducted heat pump. ENERGY STAR itself says a ducted heat pump may be the right system if you already have ductwork.

A mix also works. ENERGY STAR says mini splits can supplement an existing system, so central air can serve the main house while a mini split covers an addition or a room the ducts never reached.

Size matters for either one. Our room size calculator gives a starting BTU figure for each room. For small rooms, see our compact mini splits under 12,000 BTUs. For whole rooms and zones, see our best ductless mini split picks, and read the drawbacks of mini splits before you buy. If you are going ducted, our central air conditioner brands guide compares the main makers.

We do not give installed prices here, because they depend on your house, your ducts and your area. Get two or three written quotes, and ask each installer for the rated SEER2, EER2 and HSPF2 of the exact system. You can find a local installer through our HVAC technician finder.