Preemptive cooling for Apple Silicon
Run your Mac cooler and quieter.
Zephyr learns your Mac’s own fan curve, then leads it by a temperature offset — the fans spin up a little earlier, so the chip soaks less heat and throttles less under sustained load. It never disables Apple’s thermal protection, and it hands control back to macOS the moment you quit.
How it works
macOS keeps the fans quiet. Zephyr makes them lead.
Apple’s default curve is tuned for silence: it lets the die soak heat and throttle before the fans really move. Zephyr learns that curve, then shifts it earlier by a temperature offset — at 60 °C it asks for the RPM macOS would use at 68 °C. More airflow at every temperature, so the Mac runs cooler. Drag the offset and watch it lead.
Leading by 8 °C
driven by TCMz · CPU die hotspotTemperature offset
How far Zephyr leads the OS curve. 0 °C is exactly stock; higher means cooler, sooner.
Or pick a preset
The three built-ins Zephyr ships with. Switching one updates the curve and the menu-bar readout.
Fail-closed by design
It leads the curve. It never disables your Mac’s safety.
Overriding thermal behaviour is only acceptable if it can’t go wrong. Zephyr only ever asks for more airflow than macOS would — never less — and it holds that control on a lease that snaps back to the OS at any sign of trouble.
Never disables throttling
Apple’s thermal protection stays fully in charge. Zephyr adds airflow on top of the OS curve; it can only ask the fans to spin faster, never slower.
Hands back on quit, crash or sleep
Control lives on a cooling lease tied to the app. Quit it, force-quit it, or let the Mac sleep, and the fans return to Auto immediately.
Reverts on a thermal emergency
If the die ever reaches a critical temperature, Zephyr drops the lease and lets macOS take over with full throttling — the safe path always wins.
Clamped to hardware limits
Every target is clamped to the fan’s own minimum and maximum RPM before it’s ever written. Zephyr can’t push the hardware past what it’s rated for.
Features
A precise thermal instrument, not a hack.
Everything you’d expect from a native macOS utility — live in the menu bar, tuned from a real settings window, scriptable from the terminal.
Live in the menu bar
Die temperature, per-fan RPM and power at a glance, with a one-click preset switch — the mono readout is the product’s whole personality.
Presets & per-fan curves
Stock, Cool & Quiet, and Max Cooling out of the box — or set your own offset per fan and watch the curve update in a native settings window.
Cooling-lease CLI
Max cooling for exactly as long as a job runs. zephyr cool -- cargo build spins the fans up for the compile, then hands control straight back.
Works on fanless Airs too
No fans to drive on a MacBook Air? Zephyr runs as a pure telemetry monitor — die temperature, power and thermal pressure, no controls to fake.
Compatibility
Will it work on your Mac?
Apple Silicon (M1–M5) on macOS 14 or later. Macs with fans get full offset control; fanless MacBook Airs get monitoring only. Here’s exactly what to expect.
| Model | Fans | What you get | Driving sensor |
|---|---|---|---|
| MacBook Air (M1, M2, M3) | 0 | Monitoring only | TCMz |
| MacBook Pro 13″/14″ (base) | 1 | Full control | TCMz |
| MacBook Pro 14″/16″ (Pro, Max) | 2 | Full control | TCMz |
| Mac Studio (Max, Ultra) | 2 | Full control | TCMz + PSTR |
Pricing
Buy it once. It’s yours.
A one-time purchase, not a subscription. Try every feature free for 14 days, then buy a perpetual licence once and keep it.
- Custom fan curves, presets, and per-fan control
- Live per-fan telemetry and the cooling-lease CLI
- Fail-closed safety, always on
- Every update, no subscription
14-day free trial, everything unlocked. 14-day refund, no questions. Apple Silicon, macOS 14 and up.
Download
Get the free trial running.
A signed, notarised .dmg or a single Homebrew command, every feature unlocked. Then the one-time helper approval that lets it control your fans.
Open the .dmg, drag to Applications
The usual macOS install. Nothing unusual here.
Launch Zephyr
It’s Developer ID signed and notarised, so Gatekeeper opens it straight away — no right-click “Open anyway”, no Terminal.
Approve the helper once
Zephyr installs a small background helper to control the fans. Approve it once in System Settings → Login Items. This is the usual answer to “why won’t the fans spin?”.
Pick a preset and you’re running
Stock changes nothing, Cool & Quiet leads by 8 °C, Max Cooling by 15 °C. Switch any time from the menu bar.
FAQ