Divide BTU per hour by about 3,412 to get kilowatts of cooling — so 9,000 BTU is roughly 2.6 kW and 12,000 BTU is roughly 3.5 kW.
The two units describe the same thing
How much heat the unit can move per hour. BTU per hour is the convention in listings, kilowatts the convention on energy labels and in most European documentation. The conversion is a single division and nothing is lost in it.
Useful reference points
Nine thousand BTU is about 2.6 kW, twelve thousand about 3.5 kW, and seven thousand about 2.1 kW. Those three cover most of the portable market, which is why they recur in listings.
The trap: two different kilowatts
Cooling capacity and electrical consumption are both quoted in kW and they are not the same number. A unit with 2.6 kW of cooling may draw well under a kilowatt from the socket, because it moves heat rather than creating cold. Confusing the two produces either a wildly oversized appliance or a wildly optimistic running cost.
Where the energy label settles it
European energy labels state the cooling output and the efficiency separately, with the units written out. Reading the label rather than the listing removes the ambiguity at a glance, and it is the same document in the same format for every model on sale.
What we would not do
Compare a BTU figure from one listing against a kW figure from another without converting both, and without checking which kind of kilowatt each one means.
The questions that keep coming up
A listing gives one figure in kW and no label. Which is it?
Almost certainly the cooling capacity, because it is the larger and more flattering of the two. Electrical consumption on a portable unit of that size is usually well under half the cooling figure.
Last reviewed 9 October 2026