Concealed Duct Mini Split Systems

Concealed vs Ducted Mini Split — What's the Difference?

There isn't one. "Concealed mini split" and "ducted mini split" refer to the same product class — an indoor air handler hidden above the ceiling that delivers conditioned air through short duct runs to ceiling vents. You'll also see the terms slim-duct mini split, ducted heat pump, horizontal ducted mini split, and hidden ductless mini split used interchangeably. The naming splits along audience lines: residential shoppers tend to search "concealed mini split" because the visual outcome (no visible head) is what they want; HVAC contractors and spec writers tend to write "ducted mini split" because that describes how the air actually moves. Both refer to the same hardware. If you want a visible indoor unit instead, compare with wall mount mini splits or ceiling cassettes.

BTU to Ton Conversion for Concealed Systems

Sizing a concealed duct mini split uses the same BTU-to-square-foot math as any other mini split, but with one wrinkle: short duct runs introduce a small static-pressure penalty, so most manufacturers list the rated capacity slightly below the BTU class. Zone Air's 9K concealed is rated at 9,500 BTU; the 12K concealed is rated at 11,000 BTU. Below is the standard BTU-to-ton conversion for reference, plus where Zone Air's concealed inventory currently sits:

Zone Air's single-zone concealed inventory tops out at the 12K class. If you need more than 12,000 BTU of hidden capacity, multi-zone bundles add a second concealed head on the same outdoor condenser — usually a better fit than trying to oversize a single concealed unit, because short duct runs work best when the air handler matches the served area, not when one head pushes air through 40 ft of branch duct.

Sizing a Concealed Duct System

Concealed sizing differs from wall-mount sizing in one important way: the duct runs themselves cap how far conditioned air can travel before throw and pressure drop kill the result. Plan for short runs — 8 to 15 ft per branch — and treat the served area as the rooms within that radius, not the entire floor.

• 14×16 master bedroom + en-suite via duct branch — 224 sq ft of bedroom plus a small bath. The 9K (rated 9,500 BTU) concealed handles both spaces from one ceiling-cavity install with a short branch to the bath vent.
• 18×22 great room — 396 sq ft of open living. The 12K (rated 11K) concealed is correctly sized when ceilings are 8 ft and there's no kitchen heat load. With vaulted ceilings, derate to two heads via a dual-zone bundle instead of pushing the 12K beyond its short-duct comfort range.
• 2 adjacent bedrooms with shared ceiling cavity — tempting to feed both from one 12K with a tee branch, but separate thermostats matter for sleep. Pick a dual-zone bundle with two heads sharing one outdoor unit and you get independent control.
• Whole-house concealed — not recommended. Concealed mini splits are designed around short duct runs and a 2–4 room footprint per head. If you want hidden HVAC across an entire floor plan, the right answer is multiple concealed heads on a multi-zone outdoor unit, not one oversized head pushing air through 40+ ft of branch duct. Concealed isn't a substitute for central ducted HVAC.

How to Choose a Concealed Duct Mini Split

Three decisions, in order:

1. Confirm concealed is right for your space. Concealed wins when you have ceiling cavity, attic, or soffit access above the rooms you want conditioned and the aesthetic of a hidden indoor unit matters. If your ceiling is on a slab with no cavity, wall mount is the right pick. If you have a drop ceiling and want a visible-but-recessed unit with four-way airflow, ceiling cassettes install faster and cost less than a full concealed system.

2. Plan your duct path. Walk the ceiling cavity or attic and confirm you have headroom for the air handler (Zone Air concealed units are about 8 inches tall) plus space for short branch ducts to each room vent. Map out where the supply vents land in the rooms below and where the return-air grille goes. Soffit-mount installs are the cleanest path when an attic isn't available. If duct runs would exceed 15 ft per branch, split the load across two concealed heads via a dual-zone bundle instead.

3. Pick BTU class. Use 20 BTU per square foot of conditioned area as a starting point, derate for sun-facing walls (–15%), vaulted ceilings (–10% per foot over 8 ft), and open kitchens (–25%). A 14×16 bedroom plus en-suite lands on 9K. An 18×22 great room or master suite lands on 12K. For two separate rooms, skip single-zone concealed and pick a dual-zone bundle so each room gets its own thermostat.

The most common concealed sizing mistake we see is upsizing "for headroom." A 12K in a room that wanted 9K short-cycles, removes less humidity, and uses more electricity. Concealed installs amplify this because short duct runs make the inverter compressor sensitive to load mismatches. If you're between sizes, derate before you upsize.

What's Included with Every Zone Air Concealed System

Every concealed duct mini split ships with the indoor air handler, outdoor condenser, 16 ft pre-charged R454B refrigerant lineset, wireless remote, built-in condensate pump, mounting hardware for both indoor and outdoor units, and a 5-year parts / 7-year compressor warranty. Free shipping on every order, 45-day returns, live tech support 9–5 MST. Honest tradeoff: concealed installs cost a few hundred more than the equivalent wall mount and require ceiling cavity access plus 2–4 hours of additional install time for ductwork. In exchange you get a fully invisible indoor unit and conditioned air to 2–4 rooms from a single head.