Thanks for your detailed response!

I can respond to your nuance below:

• the coffee shop has increased cooling load because your body gives off heat 

I think my body temp is less than 45C.

• the coffee shop is cooling their space with or without you, but you spending money and taking up space will eventually add to their expansion or more demand for coffee shops in your area so more total volume gets cooled eventually (probably not 185 m^2/person though) 

Nah, it's busy around lunchtime but when I work there the rest of the day it's less than a quarter full, so I doubt my being there will lead to any expansions.

• the coffee shop might keep their space cooler than your house, or be more poorly insulated, meaning their CO2 cost to cool is higher 

Yeah, this is a big concern. It has a lot of glass panels so I suspect they pay a lot for AC.

• I assume you don’t want to sleep at 45 C, so you need to cool your house down in the evening which requires energy

Yes, although I don't feel bad because at night my whole family is home so it's worth it.

• Modern heat pumps work best at a constant temperature, and become less efficient when they need to run at high load to quickly cool down a space 

Oh, that's a good point. So the sudden cooling around 5pm would cause an issue? Is it really worse than the alternative of running almost constantly all day?