The smallest window air conditioner in 2026 is the Frigidaire FFRE053WAE at 16" H × 18.6" W × 15.4" D, weighing just 38 lbs and fitting window openings as narrow as 23". For truly narrow windows (under 23"), the Koldfront WAC6002WCO at 17.7" W fits openings as small as 18".
If your window is smaller than average, you need to match the AC's physical dimensions and minimum window requirements to your actual opening. This guide lists every compact window AC with exact measurements.
Compact Window AC Dimensions Ranked by Width
| Rank | Model | BTU | Width | Height | Depth | Weight | Min Window Width |
|---|---|---|---|---|---|---|---|
| 1 | Koldfront WAC6002WCO | 6,000 | 17.7" | 13.0" | 15.6" | 42 lbs | 18" |
| 2 | Frigidaire FFRE053WAE | 5,000 | 18.6" | 13.4" | 15.4" | 38 lbs | 19" |
| 3 | Haier QHNG06AC | 6,000 | 18.9" | 13.3" | 17.2" | 44 lbs | 19.5" |
| 4 | TCL 5W3E1-A | 5,000 | 19.0" | 13.8" | 15.0" | 40 lbs | 19.5" |
| 5 | Frigidaire FFRA051WAE | 5,000 | 19.2" | 13.0" | 15.5" | 37 lbs | 20" |
| 6 | GE AHQ05LZ | 5,000 | 19.7" | 13.5" | 17.5" | 43 lbs | 20.5" |
| 7 | Midea MAW05M1WWT | 5,000 | 19.5" | 13.6" | 16.8" | 41 lbs | 20" |
Compact Window ACs Ranked by Height (for Short Windows)
If your sash doesn't open high enough, the unit's height is the limiting factor:
| Rank | Model | BTU | Height | Width | Min Opening Height | Weight |
|---|---|---|---|---|---|---|
| 1 | Koldfront WAC6002WCO | 6,000 | 13.0" | 17.7" | 13.5" | 42 lbs |
| 2 | Frigidaire FFRA051WAE | 5,000 | 13.0" | 19.2" | 13.5" | 37 lbs |
| 3 | Haier QHNG06AC | 6,000 | 13.3" | 18.9" | 13.5" | 44 lbs |
| 4 | Frigidaire FFRE053WAE | 5,000 | 13.4" | 18.6" | 14" | 38 lbs |
| 5 | GE AHQ05LZ | 5,000 | 13.5" | 19.7" | 14" | 43 lbs |
| 6 | TCL 5W3E1-A | 5,000 | 13.8" | 19.0" | 14.5" | 40 lbs |
Check both width AND height. Your window opening must exceed the AC's physical dimensions by at least 0.5" in each direction. A unit that's 18.6" wide needs a window opening of at least 19" to allow clearance for the side panels and mounting hardware.
How to Measure for a Compact Window AC
- Raise the sash fully — remove any sash stops that limit travel
- Measure the clear opening width between inside edges of the frame
- Measure the clear opening height from sill top to bottom of raised sash
- Measure sill depth from interior edge to where the sash closes
- Check that the sill is level and can support the unit's weight
| Measurement | Where to Measure | Typical Minimum |
|---|---|---|
| Width | Between inside frame edges | 18"–23" |
| Height | Sill to bottom of raised sash | 13"–14" |
| Sill depth | Interior edge to sash closure | 3.5"–4" |
Compact ACs: Performance Tradeoffs
Smaller physical size means smaller coils, smaller fans, and less airflow, which affects performance:
| Tradeoff | Impact | Mitigation |
|---|---|---|
| Lower BTU range | Max 6,000–8,000 BTU | Size correctly for your room |
| Slightly lower efficiency | CEER typically 10.5–12.5 | Accept or buy inverter model |
| Higher noise per BTU | Smaller fans spin faster | Choose the quietest option |
| Less dehumidification | Smaller evaporator coil | Adequate for small rooms |
Example 1: Narrow Brownstone Windows — The Wongs' 1890s brownstone has 20" wide windows. The Koldfront WAC6002WCO (17.7" wide) fits with room for side panels. It cools their 150 sq ft bedroom adequately at 6,000 BTU.
Example 2: Short Window Opening — Miguel's apartment sash only opens 13.5 inches. The Frigidaire FFRA051WAE (13.0" tall) fits with just enough clearance. At 5,000 BTU, it handles his 130 sq ft room.
Example 3: Older Home, Unusual Window Dimensions — The Johnsons have 1940s windows measuring 19" wide × 14" tall. The Haier QHNG06AC (18.9" × 13.3") fits perfectly with proper side panel extension.
Key Takeaways
- The smallest window ACs are 17.7"–19" wide and fit openings from 18"–20".
- Minimum height is 13.0" — any window that opens at least 13.5" can fit the shortest compact models.
- All compact ACs are 5,000–6,000 BTU, covering rooms up to 200–250 sq ft.
- Weight ranges from 37–44 lbs — easy solo installation for any compact model.
- Measure both width and height — either dimension can be the limiting factor.
- If your window is under 18" wide, a casement/vertical AC or portable AC is needed.