Ductless Mini Split vs Central Air

By Proair Air Conditioning Services, CSLB C-20 License #776028. Published October 30, 2026. Updated October 30, 2026.

Mini split vs central air: the short comparison

A central system pushes air through ducts from one air handler. A mini split sends refrigerant through small lines to one or more wall or ceiling heads, and each head cools its own room. Almost every other difference flows from that.

Why do ducts decide most of these jobs?

Ducts lose air. ENERGY STAR says about 20 to 30 percent of the air moving through a typical duct system is lost. Ducts in a hot attic also pick up heat on the way to the room. A mini split skips that path, which is its biggest advantage.

Good ducts change the math. ENERGY STAR itself notes that homes with existing ducts may be better served by a ducted heat pump. If your ducts test well, or can be sealed at a sensible cost, you keep whole-home air movement and one filter to manage.

What happens in a 1950s attic

South Gate's median home dates to 1952, and nearly half the housing stock is from the 1940s and 1950s. Many of those homes were never designed around central air. Low roof framing leaves little room for an air handler or for supply trunks sized to move cooled air.

That does not rule out central air. It means a central air addition starts with a look in the attic and a room-by-room load calculation, before anyone picks equipment.

When does a ductless mini split win?

ENERGY STAR lists older homes without ductwork, additions and rooms with hot or cold spots as good candidates. That matches what these houses need. A ductless mini split installation makes the most sense in these cases:

• The home has wall heaters and no ducts at all.
• You added a room, a converted garage or a back unit that the main system never reached.
• A home office or bedroom runs hot and the rest of the house is fine.
• People in the home want different temperatures at the same time.
• You want cooling and heating from one outdoor unit without opening ceilings.

When is central air the better call?

Central air wins when you want every room conditioned, the home has several small rooms and you would rather not see a head in each one. It also wins on filtration, because a central return can carry a thicker media filter. Bedrooms with closed doors cool better with ducted supply than from a single head in a hallway.

Some homes in Bellflower and other postwar tracts run a package unit, where cooling and heating sit in one cabinet. Replacing a complete package system still counts as a duct-testing trigger in California, so budget for that review. Bellflower’s median home dates to 1966 and 60.7% of its occupied homes are rented (Census ACS), so the owner often makes this call.

What does each option cost to install?

The ducts swing the price more than the equipment does. HVAC Project Cost’s comparison guide, updated August 2, 2026, lists the installed figures below. They are published ranges, not South Gate bids and not Proair prices.

Read the table by what your house already has. With usable ducts, central air starts lower, and DOE notes a mini-split can cost 30 percent more than adding an AC to an existing duct system. With no ducts, one or two zones sit well under a new duct job, and at four zones the two ranges overlap.

Older houses add lines neither range may show: a panel upgrade, patching and a test of old duct wrap. Ask each bidder to list them.

Which one costs less to run?

It depends on how you live in the house. A mini split loses nothing to ducts and can sit idle in an empty room, so a household cooling two rooms can use less power. A central system cools the whole house each time it runs, and sealing its ducts narrows that gap. The trade-off is comfort: a room with its head switched off is left to warm up.

Which system cleans the air better?

Central air does, as long as the return can hold a good filter. EPA says ductless mini-splits mainly treat the room they sit in, and only while they run.

EPA’s test for a high-efficiency claim is MERV 13 or higher. Our guide to smoke and indoor air in LA County covers what to do without it. Old return slots can be thin, so ask what yours will hold before you count on this advantage.

What should you ask about permits and installation?

Either path needs a permit in South Gate, where the city's page says improvements to mechanical and electrical systems require one. Under the 2025 Energy Code, replacing central equipment triggers sealing and ECC-Rater verification of the connected ducts. An ECC-Rater (formerly called a HERS rater) is the independent tester, and contractors cannot self-certify that work.

• Sizing: ask for a Manual J load calculation. Oversized systems short-cycle, and an oversized head can run so briefly that a room feels clammy.
• Efficiency: split ACs under 45,000 Btu/h must meet 14.3 SEER2 in the Southwest region, and split heat pumps must meet 14.3 SEER2 and 7.5 HSPF2. Your quote should name the rating.
• Refrigerant: new equipment generally uses R-454B or R-32. Ask which refrigerant the quote specifies.
• Electrical: ask whether the panel can carry the new circuit, and list any upgrade as its own line.
• Upkeep: each mini split head has its own filter and drain, so more heads means more to clean.

Can you use both?

Yes, and many older homes end up there. A central system keeps the main house comfortable while a single head handles a garage conversion or back room the ducts never reached. Extending ducts into an addition can overload a system that was sized for the original house, so a separate head is often the cleaner fix.

If you are starting from a failed system, get the replacement priced first and the mini split priced as an add-on. Our AC replacement page explains what goes into that quote.

How do you decide for your own house?

1. 1

   Count the rooms you cool

   List the rooms you use on a hot afternoon. Two rooms lean toward heads. Every room leans toward central air.

2. 2

   Look for what is already there

   Registers and a return grille mean ducts. Look into the attic from the hatch, and leave old duct wrap alone.

3. 3

   Test the ducts you have

   A leakage test shows whether they are worth keeping. The replacement limit is 10% total, or 7% to outside.

4. 4

   Price the same rooms both ways

   Have each quote name the rooms, the circuit, the drain route, the permit and any testing.

Let the ducts and the rooms make the call

Sound ducts and a whole house to cool point to central air. No ducts, a low attic or one stubborn room point to a mini split. Call us with the age of your home and the rooms that run hot. We will look at the ducts, the attic and the panel, explain what fits and give you a clear, upfront quote before any work starts.