# I Built an Inbox Cleaner That's 88% Greener Than Cloud Alternatives. Here's How. > Source: > Published: 2026-06-18 11:21:12+00:00 **I had 50,000 emails in my inbox. Most cleaners wanted £8/month and my data. So I built my own.** Here's why MailBroom runs entirely on your iPhone, why that matters for privacy, and why it's 88% greener than cloud alternatives. **The Problem** Most email cleaners – like Clean Email – use cloud-based AI. That means your emails leave your device, get processed on energy-hungry servers, and contribute to data centers' 0.3% of global emissions. According to the Carbon Literacy Project, a standard email generates about 4 grams of CO₂e. With 281 billion emails sent daily in 2018, that's ~410 million tons of CO₂ annually – nearly half the emissions of commercial aviation. **The Solution ** MailBroom's AI runs entirely on your iPhone. Your emails never leave your device. Recent research from UC Riverside shows on-device AI inference can reduce energy consumption by up to 95% compared to cloud-based processing. Qualcomm confirmed similar findings – around 90% less energy per query. **Key Features** What MailBroom does differently: Smart Triage – Guides you through one sender at a time. One decision clears thousands of emails instantly. Smart Unsubscribe – Sends real RFC 8058 opt-out requests. No fake workarounds. Smart Organise – Create folders and file emails by sender with one tap. 5 free cleanups + 5 free sweeps – No credit card, no trial expiry. £0.99/mo intro / £1.99 regular – Cancel anytime. **Architecture** MailBroom connects to any IMAP server. Credentials are stored in iOS Keychain. AI classification happens on-device using Core ML. No external servers. No data harvesting. **Results** A 50,000-email inbox cleanup with MailBroom saves the equivalent of ~200 kg of CO₂ that would have been emitted over the lifetime of those emails remaining in the cloud. Try MailBroom free today.