The largest window air conditioner commonly available in 2026 is the Friedrich CCF24A30A at 24,000 BTU (EER 10.3), capable of cooling rooms up to 1,500 sq ft. At 130 lbs and requiring a 230V outlet, these are serious cooling machines — not your typical bedroom window AC. Units above 18,000 BTU require 230V power (not standard 120V), professional-grade support brackets, and two-person installation.
If you need to cool 700+ sq ft without central air or a mini split, a high-capacity window AC is your most affordable option at $550–$800 upfront.
Largest Window ACs Ranked
| Rank | Model | BTU | EER/CEER | Noise | Voltage | Weight | Coverage | Price |
|---|---|---|---|---|---|---|---|---|
| 1 | Friedrich CCF24A30A | 24,000 | 10.3 EER | 56 dB | 230V | 130 lbs | 1,200–1,500 sq ft | $780 |
| 2 | LG LW2521ERSM | 25,000 | 10.2 EER | 56 dB | 230V | 125 lbs | 1,300–1,600 sq ft | $720 |
| 3 | Frigidaire FFRA252WAE | 25,000 | 10.0 EER | 57 dB | 230V | 120 lbs | 1,300–1,600 sq ft | $650 |
| 4 | Friedrich CCF18A30A | 18,000 | 10.5 EER | 54 dB | 230V | 100 lbs | 700–1,000 sq ft | $620 |
| 5 | LG LW1823IVSM | 18,000 | 10.8 EER | 50 dB | 230V | 90 lbs | 700–1,000 sq ft | $650 |
| 6 | Frigidaire FFRE183WAE | 18,000 | 10.5 EER | 52 dB | 230V | 95 lbs | 700–1,000 sq ft | $560 |
| 7 | Keystone KSTAW18CE | 18,000 | 10.0 EER | 54 dB | 230V | 98 lbs | 700–1,000 sq ft | $500 |
230V Electrical Requirements
All window ACs above 15,000 BTU require 230V (also called 220V or 240V) power. This is NOT your standard wall outlet.
| Specification | 120V (Standard) | 230V (Required 18K+ BTU) |
|---|---|---|
| Outlet type | NEMA 5-15 or 5-20 | NEMA 6-20 or 6-30 |
| Circuit breaker | 15A or 20A | 20A or 30A |
| Wire gauge | 14 or 12 AWG | 12 or 10 AWG |
| Installation cost (new circuit) | N/A (already exists) | $200–$500 |
Do You Already Have a 230V Outlet?
Common locations where 230V outlets already exist:
- Near a clothes dryer (NEMA 14-30 — different plug, needs adapter or new outlet)
- Near a stove/range (NEMA 14-50 — also different plug type)
- In older homes that previously had a window AC (may have NEMA 6-20)
Don't use a voltage adapter or converter. If your outlet type doesn't match the AC's plug, have an electrician install the correct outlet. Adapters can overheat and cause fires. A new 230V, 20A circuit with the correct outlet costs $200–$500 installed — a worthwhile safety investment.
Weight and Installation Challenges
Large window ACs are genuinely heavy and require careful planning:
| BTU | Typical Weight | People Needed | Bracket Required? |
|---|---|---|---|
| 15,000 | 75–82 lbs | 2 people | Strongly recommended |
| 18,000 | 90–100 lbs | 2 people | Required |
| 20,000 | 100–115 lbs | 2 people | Required |
| 24,000–25,000 | 120–130 lbs | 2–3 people | Required (heavy-duty) |
Support Bracket Sizing
For units over 90 lbs, a standard 80 lb bracket won't work. You need:
| AC Weight | Minimum Bracket Rating | Recommended Models |
|---|---|---|
| 75–90 lbs | 120 lbs | Frost King ACB160H, TopShelf TSB-2438 |
| 90–115 lbs | 160 lbs | AC Safe AC-160, Frost King ACB160H |
| 115–130 lbs | 200 lbs | EZ-AC Commercial, Custom fabrication |
Cooling Capacity for Large Spaces
BTU-to-Room-Size Chart (Large Rooms)
| Room Size (sq ft) | Standard Conditions | Sunny Room | High Ceiling (10'+) |
|---|---|---|---|
| 700–850 | 18,000 BTU | 20,000 BTU | 21,000–22,000 BTU |
| 850–1,000 | 20,000 BTU | 22,000 BTU | 23,000–24,000 BTU |
| 1,000–1,200 | 21,000–23,000 BTU | 24,000 BTU | 25,000+ BTU |
| 1,200–1,500 | 24,000–25,000 BTU | 27,000+ BTU (need 2 units) | 28,000+ BTU (need 2 units) |
When Two Smaller Units Beat One Large Unit
For spaces over 1,000 sq ft, two smaller ACs (e.g., two 12,000 BTU units) often outperform one large AC:
| Factor | One 24K BTU Unit | Two 12K BTU Units |
|---|---|---|
| Total BTU | 24,000 | 24,000 |
| Total price | $650–$780 | $800–$1,000 |
| Electrical | 230V (may need new circuit) | Two 120V (existing circuits) |
| Weight per unit | 120–130 lbs | 60–72 lbs each |
| Cooling distribution | Uneven (warm far corners) | Better (two points of cooling) |
| Noise | 54–57 dB (one loud source) | 43–46 dB × 2 (two quieter sources) |
| Inverter option? | No (none at 24K BTU) | Yes (LG, Midea at 12K BTU) |
| Efficiency (CEER) | 10.0–10.3 EER | 11.8–15.15 CEER each |
Two 12,000 BTU inverter units are typically more efficient, quieter, and better distributed than one 24,000 BTU unit. The only advantage of one large unit is simplicity (one window, one installation). If you have two available windows, the dual-unit approach is superior in almost every way.
Example 1: Open Loft Space (900 sq ft) — Tyler's loft has no central AC and one large window. He installed a Friedrich 18,000 BTU unit ($620 + $45 bracket + $350 electrician for 230V outlet = $1,015 total). The unit cools the entire loft to 74°F on 95°F days, though the far end is 3–4°F warmer than near the unit.
Example 2: Two Units vs. One — The Smiths' 1,100 sq ft ranch home needed cooling but lacked ductwork. They compared one 24K BTU unit ($780 + $500 electrical = $1,280) vs. two LG 12K BTU Dual Inverters ($500 × 2 = $1,000, existing 120V outlets). They chose two units: better distribution, 43 dB each vs. 56 dB, and CEER 15.15 vs. EER 10.3. Total annual electricity: $128 (two inverters) vs. $188 (one large unit).
Example 3: Workshop Cooling — Frank's 800 sq ft detached workshop has no insulation and full sun exposure. He installed a Frigidaire 25,000 BTU ($650) with existing 230V from the workshop's table saw circuit. It handles the extreme heat load (poor insulation + sun + equipment heat) that a 12,000 BTU unit couldn't. Workshop cooling is one case where maximum BTU outweighs efficiency concerns.
Running Costs: Large ACs Are Expensive to Operate
| Unit | BTU | EER/CEER | Monthly Cost (8 hrs/day)* | Annual Cost (4 months)* |
|---|---|---|---|---|
| Friedrich CCF24A30A | 24,000 | 10.3 | $47 | $188 |
| LG LW2521ERSM | 25,000 | 10.2 | $49 | $198 |
| Frigidaire FFRA252WAE | 25,000 | 10.0 | $50 | $202 |
| Friedrich CCF18A30A | 18,000 | 10.5 | $34 | $138 |
| LG LW1823IVSM | 18,000 | 10.8 | $33 | $135 |
| Two LG LW1223IVSM (12K each) | 24,000 total | 15.15 | $32 total | $128 total |
At $0.168/kWh.
The two-unit inverter approach costs $60–$74 less per year to operate than a single large unit at equivalent total BTU.
Key Takeaways
- Largest available: 25,000 BTU (LG, Frigidaire) covering up to 1,600 sq ft.
- All units above 15,000 BTU need 230V power — budget $200–$500 for electrical work if you don't have an outlet.
- Weight ranges from 90–130 lbs — always use two people and a heavy-duty support bracket.
- Two 12,000 BTU inverter units often beat one 24,000 BTU unit on efficiency, noise, and cooling distribution.
- No inverter compressor options exist above 15,000 BTU for window ACs — large units are all fixed-speed.
- Running costs are $135–$200/year for large units vs. $128 for two efficient 12K units.
- Best use case for a single large unit: one available window, or non-residential spaces (workshops, garages) where efficiency and noise are secondary.