Two different types of power
Cooling capacity describes how much heat a unit can remove. Electrical input describes the electricity it uses. A unit with 3.5 kW of cooling capacity does not therefore automatically draw 3.5 kW of electricity.
Convert the units
1 kW of cooling is approximately 3,412 BTU/h. A 12,000 BTU/h rating therefore means roughly 3.52 kW of cooling capacity. Product names often shorten this to “BTU”; our calculations use the rate, BTU/h.
Floor area is only the starting point
Ceiling height, sun exposure, insulation, glazing and indoor heat sources all affect the load. Our calculator uses an educational assumption of 30–50 W per cubic metre, followed by a sunlight factor. It is not a sizing standard or a professional heat-load assessment.
Compare like with like
Check the test method and conditions in the technical documents. A nominal rating does not represent every loss in a real installation, including those around the window and exhaust duct. Extra rated capacity does not reliably fix poor exhaust routing.
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