Window AC vs. mini-split
A window unit is cheap to buy and easy to fit; a mini-split costs more up front but runs for less, is quieter and also heats.
For one room you cool a few months a year, a window unit wins. For a room you heat or cool most of the year, a mini-split usually pays for itself.
Side by side
| Window AC | Mini-split | |
|---|---|---|
| Typical efficiency (12,000 BTU) | 15.0 CEER (best 16.8) | 13.0 EER2, 23.2 SEER2 |
| Heating | Some models (heat pump mode) | Yes, 10.2 HSPF2 typical |
| Installation | DIY, in an hour | Usually a pro; DIY kits exist |
| Noise indoors | Compressor in the window | Compressor outside |
| Window | Blocks part of it | Stays free |
| Rooms | One | One per indoor head; multi-zone for more |
| Certified models | 34 at 12,000 BTU | 275 at 12,000 BTU |
Yearly cooling cost, 12,000 BTU
| City | Window AC | Mini-split | Saved |
|---|---|---|---|
| Phoenix, AZ | $207 | $134 | $73 |
| Houston, TX | $179 | $116 | $63 |
| Miami, FL | $216 | $139 | $76 |
| Atlanta, GA | $93 | $60 | $33 |
| New York, NY | $119 | $77 | $42 |
| Chicago, IL | $72 | $47 | $25 |
| Seattle, WA | $14 | $9 | $5 |
Typical certified units of each kind: window 15.0 CEER, mini-split 23.2 SEER2. Cooling hours from each city's cooling degree days, at the state's average electricity price. CEER is a 95°F rating and SEER2 a seasonal one, so the window column is a little pessimistic in mild climates.
Questions
Common questions
- Is a mini-split more efficient than a window air conditioner?
- Yes. A typical certified 12,000 BTU window unit is rated 15.0 CEER; a typical 12,000 BTU mini-split is rated 13.0 EER2 at the same 95°F test point and 23.2 SEER2 over a cooling season. Even at 95°F the mini-split uses about -15% less electricity, and the gap grows on milder days when its inverter slows down.
- Which is cheaper, a window AC or a mini-split?
- To buy and install, a window unit by far: it costs a few hundred dollars and you fit it yourself. A mini-split usually costs thousands installed (less as a DIY kit). To run, the mini-split is cheaper, and it also heats. A window unit makes sense for one room you cool a few months a year; a mini-split pays back in rooms you cool or heat most of the year.
- Is a mini-split quieter than a window AC?
- Usually, yes. A mini-split keeps the compressor outside and only a fan inside. A window unit has the compressor in the window; U-shaped designs move it outside the glass, which helps.
- Can a window air conditioner heat like a mini-split?
- A few can: some window units run in reverse as a small heat pump. Mini-splits are built for heating too (typical 10.2 HSPF2), and cold-climate models keep heating far below freezing.