Portable AC BTU Calculator
Size a portable air conditioner for a single room using square footage, climate zone, ceiling height, insulation, humidity, and setup details like hose type and vent length. Includes a planning-grade DOE SACC estimate.
Updated for 2026 DOE SACC standards and current portable AC models.
On this page: Calculator · Sizing chart · SACC vs BTU · Single vs dual hose · Sizing tips · Alternatives · FAQ
Can you install a window unit? A window AC is typically more efficient and cheaper to run. For a deeper factor-by-factor cooling load, use the advanced BTU calculator.
Portable AC sizing in one sentence
Start with your room BTUs, then size up for humidity, single-hose units, and long vent hoses. A 200 sq ft room needs roughly 8,000–10,000 BTU (marketing). If you shop by DOE ratings, the calculator also shows a planning-grade SACC equivalent.
Portable ACs are typically less efficient than window units. If you can install one, try the window AC calculator. For heating needs, try the space heater calculator.
Portable AC sizing chart by room size
Standard portable AC sizes and the rooms they fit. Based on average insulation, moderate sun, Zone 4, single-hose unit. Adjust up for hot climates, kitchens, heavy sun, or high humidity.
| Room (sq ft) | Marketing BTU | Approx. SACC | Shop |
|---|---|---|---|
| 100–200 | 8,000 | ~5,200 | 8,000 BTU |
| 200–350 | 10,000 | ~6,500 | 10,000 BTU |
| 350–450 | 12,000 | ~7,800 | 12,000 BTU |
| 450–550 | 14,000 | ~9,100 | 14,000 BTU |
| 550+ | 14,000+ or 2 units | — | Consider window AC or mini split |
Dual-hose units perform noticeably better than single-hose at every size. If your room is borderline between sizes, a dual-hose unit at the lower tier may outperform a single-hose at the higher tier.
SACC vs “BTU” on the box
Portable air conditioners often list a large BTU number in product titles, but since 2024 the DOE requires a SACC (Seasonally Adjusted Cooling Capacity) rating that better reflects real-world delivered cooling. SACC is typically 25–35% lower than the marketing BTU because it accounts for heat re-entering the room through exhaust gaps and infiltration air.
This calculator uses marketing BTU for the primary recommendation (since that's how most units are still sold) and shows a planning-grade SACC equivalent so you can compare models more fairly. When shopping, look for both numbers on the box — the SACC is usually labeled “DOE cooling capacity” or “SACC.”
| Marketing BTU | Approx. SACC (single hose) | Approx. SACC (dual hose) |
|---|---|---|
| 8,000 | ~5,200 | ~5,800 |
| 10,000 | ~6,500 | ~7,200 |
| 12,000 | ~7,800 | ~8,600 |
| 14,000 | ~9,100 | ~10,100 |
Browse common sizes: 8,000 BTU · 10,000 BTU · 12,000 BTU · 14,000 BTU · all portable ACs.
Single-hose vs dual-hose portable AC
A single-hose portable AC exhausts hot air out the window, but it also pulls replacement air from the rest of your home (or from outside through gaps). This creates negative pressure that can reduce comfort and effectively lower performance by 20–35%.
Dual-hose models bring outside air for the condenser separately, so they don't depressurize the room. A dual-hose unit often performs like a single-hose unit one size larger. They cost $50–$150 more but deliver noticeably better cooling, especially in hot or humid climates.
| Factor | Single hose | Dual hose |
|---|---|---|
| Cooling efficiency | Lower (SACC ~65% of BTU) | Better (SACC ~72% of BTU) |
| Room pressure | Creates negative pressure | Neutral pressure |
| Price | $250–$500 | $350–$650 |
| Setup complexity | Simpler (one hose) | Slightly more (two hoses) |
| Best for | Occasional use, small rooms | Primary cooling, hot climates, larger rooms |
If your room gets lots of sun, a window insulation kit ($10–30) reduces heat gain and makes any portable AC more effective.
Portable AC sizing tips
Hose and sealing
Keep the vent hose short and as straight as possible — each extra foot over 5 ft reduces delivered cooling by roughly 1%. Seal air leaks around the window kit, door gaps, and electrical outlets with weatherstripping to stop hot air infiltration.
Humidity and noise
Humidity matters: in humid areas, the AC works harder on dehumidification. Consider a dedicated dehumidifier to offload that work, or choose a dual-hose unit which handles humidity better. Bedroom use: portable ACs typically run 50–56 dB. If you need quiet sleep, a mini split (19–32 dB indoors) is significantly quieter. For any portable in a bedroom, look for a model with “sleep mode” that drops to the lowest fan speed.
Helpful add-ons: hygrometer ($10–15) · weatherstripping ($5–15) · thermal leak detector ($25–40) · energy monitor ($20–30).
Reduce your cooling load before buying
Small improvements can let you buy a smaller, cheaper portable AC:
Window film / reflective insulation ($10–30) — blocks solar heat through south/west windows. Weatherstripping ($5–15) — seal gaps that let hot air in. Door sweeps ($8–15) — block drafts under doors. Outlet gaskets ($5) — stop air infiltration on exterior walls.
Dropping from a 12,000 to a 10,000 BTU unit saves $50–$100 on the unit and uses 15–20% less electricity. A ceiling fan makes a room feel 3–4°F cooler, often letting you set the AC higher. Add smart scheduling with a smart AC controller ($25–60) for auto-off when you leave.
When to choose something other than a portable AC
| Situation | Better option | Why |
|---|---|---|
| Double-hung windows available | Window AC | More efficient, quieter, cheaper to run |
| Need heating too | Mini split or heat pump | Year-round heating + cooling in one system |
| Room over 500 sq ft | Mini split or window AC | Portable ACs struggle above 500 sq ft |
| Bedroom — noise is critical | Mini split | Compressor is outside (19–32 dB indoors) |
| Whole-home cooling needed | Central AC | One system cools the entire home via ducts |
| Humidity is the main problem | Dehumidifier | Removes moisture more efficiently than AC alone |
Frequently asked questions
Is a portable AC as effective as a window AC?
Not usually. Window units deliver more cooling per watt and are generally more efficient because the hot side of the compressor sits outside the room. A portable AC keeps everything indoors, radiating some heat back into the space. If your windows support a unit, the window AC calculator will likely recommend a smaller, cheaper, quieter option.
What portable AC size do I need for a bedroom?
A typical 150 sq ft bedroom needs an 8,000 BTU portable AC with average insulation. Larger bedrooms (200–300 sq ft) or hot climates may need 10,000 BTU. For bedrooms, noise matters — portable ACs typically run 50–56 dB. If you're sensitive, a mini split runs at 19–32 dB indoors. Use the calculator above for your exact setup.
What is SACC and why is it lower than the BTU on the box?
SACC (Seasonally Adjusted Cooling Capacity) is a DOE rating that accounts for heat re-entering the room through exhaust gaps and infiltration air. It's typically 25–35% lower than the marketing BTU number. A unit labeled 12,000 BTU may have a SACC of only ~8,000. See the full SACC explanation above. This calculator shows both numbers for fair comparison.
Single hose vs dual hose — which is better?
Dual-hose units cool more effectively because they don't depressurize the room. They effectively perform like a single-hose unit one size larger. The tradeoff is slightly more complex setup (two hoses) and $50–$150 higher cost. For hot climates, large rooms, or heavy daily use, dual-hose is worth the premium. See the comparison table above.
How much electricity does a portable AC use?
A typical 10,000 BTU portable AC draws 900–1,100 watts and costs $40–$70 per month running 6–8 hours per day at average US electricity rates ($0.16/kWh). Larger 14,000 BTU units draw 1,200–1,500 watts. Portable ACs use 10–20% more electricity than window ACs of equivalent capacity. Track your actual usage with an energy monitor, or estimate costs with the energy cost calculator.
Can I cool two rooms with one portable AC?
A portable AC is most effective in the room where it's placed. You can roll it between rooms (that's the appeal), but it won't cool an adjacent room through a doorway very well — expect a 40–60% drop-off. For two rooms, two smaller units or a multi-zone mini split with a head in each room is far more effective.
What's the fastest way to get a more precise load calculation?
Use the advanced BTU calculator for a 12-input room analysis including windows, ductwork, and room type. For a professional, code-grade sizing, get a Manual J load calculation or an HVAC quote.
Save on summer cooling costs
A smart AC controller ($25–60) adds scheduling and auto-off when you leave — saving 10–20% on electricity. Works with any portable AC that has a remote control. Estimate savings with the energy cost calculator.
Want a longer-term solution? Compare: window AC · mini split · SEER savings · equipment by BTU.