Understand the space
An L-shaped room, partitions or an open kitchen can limit air distribution across 40 m². Sketch the connected space instead of simply adding together the areas of separate rooms.
Match the setup to your use
Claims such as “up to 40 m²” depend on conditions. Ask what those conditions are. Extensive glazing or a top-floor location may call for a more detailed cooling-load assessment.
A transparent starting estimate
At 40 m² with a 2.5 m ceiling, our central assumption of 40 W/m³ gives 4.0 kW of cooling, about 13,648 BTU/h before the sunlight adjustment. This is an educational scenario, not a product recommendation. Adjust the assumptions in the calculator.
Check before buying
Window type and compatible kit; hose route; footprint and clearances; capacity and test method; noise at the setting you will use; electrical input. Even a well-sized unit depends on an appropriate installation.
Sources and methodology
These sources explain the technical context. They do not validate FREATH ONE or our calculator assumptions.
U.S. Department of Energy — Portable Air ConditionersOFEN / BFE — Étiquette-énergie / Energieetikette