Quick comparison
Quick answer: for a bedroom or office up to ~18 m², a 9000 BTU portable unit (like the Equation COOL9K2 or Comfee/Midea) is the right pick; for larger or very sunny rooms, step up to 12000 BTU; and for winter use choose a heat-and-cool model such as the De'Longhi Pinguino.
Choose by function and room size. For a bedroom or office up to ~18 m², 9000 BTU is enough; for larger or very sunny rooms, step up to 12000 BTU.
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Equation COOL9K2
what we rentGreat price/performance. It's the unit we deliver for rental.
De'Longhi Pinguino
heat & coolReference brand, also heats in winter. Good all-year option.
Olimpia Splendid Dolceclima
quietAmong the quietest in its class; inverter version saves energy.
Comfee / Midea Portable
best valueBudget option for a single room. Good for tight budgets.
AEG / Trotec 12000
large roomsMore power for large rooms or sun-exposed flats.
Specs are indicative by category; check exact specs and current price on each retailer's link.
Only need it for the summer? Rent instead of buy.
If it's for 1–3 months of heat, buying an AC that then gathers dust 9 months a year rarely pays off. AC Rental Lisbon delivers a 9000 BTU portable air conditioner across Lisbon and Greater Lisbon the same day, with no fixed installation and no contract. From €40/day, €210/week or €450/month, with a refundable €100 deposit.
How many BTU do I need? (guide by m²)
BTU measures cooling capacity. The rule of thumb for Lisbon's climate, with strong summer sun:
| Room size | Recommended BTU | Example |
|---|---|---|
| Up to 12 m² | 7000–9000 BTU | Small bedroom, office |
| 12–18 m² | 9000 BTU | Bedroom, studio (our rental model) |
| 18–25 m² | 10000–12000 BTU | Small living room, suite |
| 25–35 m² | 12000–14000 BTU | Large living room, open space |
With strong sun exposure, a top floor or high ceilings, step up one BTU level.
Cooling only or heat & cool?
Cooling only is cheaper and enough if you just want to beat the summer heat. Heat & cool (heat pump) costs more but doubles as a heater in winter — worth it if you want a single unit all year.
Is inverter worth it?
Inverter models adjust their power instead of switching on/off, so they're quieter and use less electricity — worth it if you run the AC many hours a day or all summer. For occasional use (a single heatwave), a cheaper on/off model is fine.
Noise
A portable unit makes the normal noise of this type of equipment — typically 50–65 dB. For the bedroom, look for models with a night/silent mode (≤ ~54 dB). It's not as quiet as a wall split.
Installation and the hose
All portables vent hot air through a hose that goes out of a window, door or balcony, with a sealing kit included. It plugs into a normal socket. No works, no drilling — ideal for rented flats and historic centres where you can't install splits.
FAQ
What's the best portable air conditioner in 2026?
It depends on use: for a bedroom, a quiet 9000 BTU is enough; for year-round use, a heat/cool inverter; for large rooms, 12000 BTU. See the comparison above.
Buy or rent?
For permanent use, buying pays off. For 1–3 summer months, renting is usually cheaper and saves you storing the unit in winter.
How much power does it use?
A 9000 BTU unit is around 800–1000 W. See our electricity-use guide.