What a Ductless Mini Split System Actually Is
Classic AmericaOct 28th 20264 min read
The short answer
- A ductless mini split system has an outdoor unit, a wall-mounted head indoors, and two copper lines connecting them. There's no ductwork and no central air handler.
- Every mini split we sell is an inverter heat pump, so it cools in summer and heats in winter. The compressor speeds up and slows down to match what your room needs.
- Single zone means one head: 9,000 (23 SEER2, up to 400 sq ft), 12,000 (19 SEER2, up to about 550 sq ft), or 23,000 (208/230V, up to 1,400 sq ft, 17 SEER2).
- Our only multi-head system is DUET: an 18,000 BTU outdoor unit with two 9,000 BTU heads, 24 SEER2 non-ducted, R-454B, 208/230V, listed at $2,065.
The three pieces
“Ductless mini split system” is the name for that trio. The outdoor unit holds the compressor, coil, and fan. The indoor head simply moves room air across a coil, and the line set carries refrigerant, not air. That's why a closed door stops a single head in its tracks: the air never makes it around the corner into the next room.
Our 9,000 BTU system and both 12,000 BTU systems are 115V. The 23,000 BTU system is 208/230V, and so is DUET. The window air conditioners on our site are a different kind of product: they cool only, and they sit in your window.
| The room you have | The system | Power |
|---|---|---|
| Bedroom or office, up to about 400 sq ft | 9,000 BTU · 23 SEER2 · $695 | 115V |
| One larger room, up to about 550 sq ft | 12,000 BTU · 19 SEER2 · $735 | 115V |
| Same class, smaller published band | 11,500 BTU · 17 SEER2 · $769.50 | 115V |
| One big open area | 23,000 BTU · $1,450 | 208/230V · 17 SEER2 |
| Two rooms with doors between them | DUET · 24 SEER2 · $2,065 | 208/230V |
What an inverter does
An inverter compressor runs at variable speed. Older air conditioners ran flat out, stopped, and then started up again. An inverter slows down once the room gets close to your setting and holds a steadier temperature. Those longer, quieter runs are also why a right-sized inverter dries the air better than an oversized unit that short-cycles. We explain the humidity side in why sizing controls humidity.
Published cooling ratings in this lineup are 23 SEER2 on the 9,000 BTU model, 19 and 17 on the 12,000 BTU models, 24 SEER2 non-ducted on DUET, and 17 SEER2 on the 23,000 BTU model.
From the spec sheet
- 9,000 BTU/h cooling · 0.75 ton
- 23 SEER2
- 115V
- Up to 400 sq ft
- Heating nameplate 9,500 BTU/h
From the spec sheet
- 18,000 BTU/h cooling · 1.5 tons
- 24 SEER2, non-ducted
- 208/230V
- Two 9,000 BTU indoor heads on one outdoor unit
- Heating nameplate 20,000 BTU/h
Pick the head for the room you have, not the biggest carton. The Size Finder does the sun and ceiling math, and mini splits lists every system.
Bedroom, office, or a second room
If you're shopping for a bedroom or office, you're usually looking at 9,000 BTU: one closed room, 115V, 23 SEER2, covering up to about 400 square feet under typical conditions. A home office full of computers runs a little warmer than an empty bedroom of the same size, which is why the Size Finder adds a small office allowance. Two closed rooms, like a bedroom and an office, call for DUET rather than a bigger single head. A garage or workshop is a different load again, so start with mini splits for garages and shops, then run the calculator with the shop type selected.
What you can plan, and what a pro connects
- You can pick the wall, measure the line-set run, and confirm your voltage before you order anything.
- A licensed HVAC technician connects the refrigerant lines, pulls a vacuum, and releases the factory charge.
- A licensed electrician provides the dedicated circuit. Even a 115V mini split isn't just a cord plugged into a shared outlet.
- You're covered for 5 years on the compressor and 1 year on other parts. Keep in mind that a non-professional install can put that warranty at risk.
A system is more than a single number
- Please don't buy the 23,000 BTU head for two closed rooms. Air from one head won't reach the room behind the door.
- The 23,000 BTU spec sheet is rated 17 SEER2. Don't mistake an older SEER figure for that rating.
- DIY stops at planning the mounting location and the path of the lines. Refrigerant and electrical work are for licensed pros.
Match the system to the rooms
Run each room through the Size Finder, then line up your finalists in the model comparison. The Install Planner checks line length and power against the model you picked. Your equipment ships free, in one box on a freight pallet. The list prices above are for the equipment only. Installation labor is separate, and a published install-cost range that already includes equipment shouldn't be added on top of a unit you've already bought.
FAQ
Common questions
What is a ductless mini split system?
It's an outdoor inverter heat pump, one or more indoor heads, and a refrigerant line set, with no ducts. Classic America systems both cool and heat.
Are these inverter mini splits?
Yes. Every Classic America mini split uses a variable-speed inverter compressor. The window units on our site are cooling-only and a different kind of product.
Can I install it myself?
You can plan the placement and measure the run. The refrigerant connections and the electrical circuit should be handled by licensed pros. You're covered for 5 years on the compressor and 1 year on parts, and a non-professional install can put that at risk.
