MailBroom

I had 50,000 emails sitting in my inbox and got curious what that actually costs, energy-wise. Turned into a proper rabbit hole:

A standard email generates ~4g of CO2e. One with a big attachment can hit 50g.
Scaled globally, email adds up to roughly 410 million tons of CO2e a year — nearly half of what commercial aviation emits.
Most inbox cleaners (Clean Email, SaneBox, etc.) run their AI in the cloud — so the tool "fixing" your clutter is burning energy in the same data centers causing the problem.
That last point is what actually shaped the build. I made MailBroom run its AI entirely on-device — no cloud processing, nothing leaves the phone. Research on on-device vs. cloud inference (UC Riverside, Qualcomm) shows 75-95% lower energy use for on-device — so the cleanup itself doesn't add to the footprint it's solving.

Wrote up the full numbers here if anyone's curious about the research: [link]

Curious if this resonates with other builders — anyone else factoring energy/carbon into architecture decisions, or is this mostly a "nice to have" story that doesn't move the needle with users in practice?