What is K BTU/HR versus BTU/HR for a cooling system mean?

[Bruce P.]

Hi,

So my friend's dad is building a ~600 sq ft ADU in southern California and on the drawings it says:

"Per Title 24, the BTU/HR rating for the equipment are:

Total water heater: 199.7K BTU/HR

Total heating equipment: 205K BTU/HR

Total Cooling System: 100.5K BTU/HR"  

When looking at air conditioning systems, I see them being sold as something like "4 tons, 48000 cooling BTU". 

What does the "K" in "100.5K BTU/HR" mean and how do I map that to "cooling BTU" when ordering a unit?

Thanks!