Installations work is neither different from the various HVAC project and service. This is just one aspect of HVAC. Installation usually requires more physical labor than service. The technician may have work with ductwork or fabricates, and those tasks will require much more strength than something like a quick filter replacement.
The HVAC service part is often more stressful mentally than installation. When the technician must solve complex issues or analyze particular issues, it could be a burden on your brain. It could be exhausting mentally when attempting to diagnose the issue. Techs can also experience difficulties communicating with customers in order to fix the issue.
A technician typically has scheduled work hours to complete installation. Service aspects of HVAC may have an uncertain timetable. It could mean working nights and weekends, that could be problematic for many people. The video below explains the differentiators between HVAC job.