Short answer
Use Activity Monitor for a deep, general-purpose view of processes, CPU, memory, energy impact, disk, and network activity. Use Battery Hog when you want total battery-side watts, runtime context, project-level development workloads, thermal history, charge history, and sleep-blocker guidance in one focused investigation.
| Capability | Battery Hog | Activity Monitor |
|---|---|---|
| Installed by default | No | Yes |
| General process inspection | Focused view | Excellent |
| Energy Impact / 12 hr Power | Separate impact ranking | Native columns |
| Whole-Mac live battery-side watts | Prominent | Not the core view |
| Group dev workers by project | Yes, heuristically | Manual investigation |
| Thermal-pressure attribution | Recent likely contributors | Manual cross-reference |
| Sleep-blocker guidance | Assertions + next action | Preventing Sleep column |
| Charge/drain history | Battery-focused views | Not its job |
What both tools cannot honestly promise
Neither should be described as a perfect per-app watt meter. Battery Hog’s live watts represent the whole Mac; its app and workload ranking uses other signals. A process that is active at the same moment as high draw may be a contributor without being the only cause.
Why use both?
Battery Hog can tell you that a project workload is a likely contributor. Activity Monitor can then help you inspect an individual process in depth. They are complements more often than replacements.