Understand the space
In a 20 m² room, floor space matters quickly. Measure the route around the bed or desk and the distance to the window. Keep the required ventilation clearances without making everyday movement awkward.
Match the setup to your use
For a bedroom, compare noise during real operation and the option to pre-cool before bedtime. In an office, screens and people add heat: equal floor areas do not necessarily need equal cooling.
A transparent starting estimate
At 20 m² with a 2.5 m ceiling, our central assumption of 40 W/m³ gives 2.0 kW of cooling, about 6,824 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