Most HVAC design is Imperial:
BTUs* for heat
Degrees Fahrenheit wet bulb and dry bulb for temperature
Grains per pound for relative humidity
Chances are your thermal comfort in the USA can be attributed to Imperial-unit-based "real work".
One of the first equations recent graduates learn in their practical education is:
That 1.08 has units of (BTU * minutes) / (feet^3 * hours * degrees Rankine)
ASHRAE publications (engineers' bibles for heating and refrigeration design) have both IP and SI editions, but the current standard for equipment specification and engineered design is Imperial.
*or even Tons (the energy required to melt one short ton of ice in 24 hours) as a rate of cooling. One ton is defined as 12,000 BTU/hour, but in reality about 11500 BTU/hour would melt a short ton of ice in 24 hours.