Notes on heat,
and building on Tesla's API
What actually heats a parked car, how Tesla's signed-command protocol works under the hood, and the incidents we've hit building VentMode on top of it.
Cabin Overheat Protection, explained: what it does, what it costs, and where it stops
A complete guide to Tesla's Cabin Overheat Protection: how to turn it on, the difference between On and No A/C, the 105F target and the 12-hour limit, what it draws from the battery, and the specific gaps that automatic window venting fills.
What a hot summer actually costs in battery — and how venting gets it back
The greenhouse effect doesn't just make a parked Tesla uncomfortable, it makes Cabin Overheat Protection burn real range to fight it. A rough, honest accounting of what that costs over a summer, and why venting gets the same result for nothing.
Which cars actually need window venting — and which ones already do it for you
The parked-car heat problem isn't Tesla-specific. Here's how it plays out across EVs and gas cars, which manufacturers already automate some version of it, and where a car without that feature is left exposed.
Connecting your Tesla to VentMode: what actually happens when you sign in
A walkthrough of the setup flow — Tesla's official OAuth login, the permissions VentMode actually requests, and why the first vent or close can take a minute the first time.
Venting beats Cabin Overheat Protection. Tesla just won't do it for you.
Cracking the windows is the more effective way to cool a parked Tesla, and it costs no battery. Cabin Overheat Protection spends real range doing a worse job. Tesla makes venting a manual, one-tap action instead of an automatic setting, most likely for liability reasons. That gap is exactly what VentMode closes.
Why VentMode costs $29/year: the Tesla API bill behind the price
VentMode's price isn't arbitrary. Every automatic vent and close wakes your Tesla over Tesla's Fleet API, and Tesla bills per request. Here's the actual cost structure behind $29/year, and why it's still a bargain next to what it protects.
What it actually takes to send a signed command to a Tesla
A from-the-implementation look at Tesla's Vehicle Command Protocol — the ECDH handshake, HMAC-SHA256 signing, and replay-protection counter that stand between an API call and your car's windows actually moving.
Cabin Overheat Protection vs. venting: the real trade-off Tesla doesn't spell out
Tesla's Cabin Overheat Protection runs the A/C while you're parked. Venting cracks the windows instead. Here's what each actually costs you in range and security, and when each one is the right call.
Why a parked Tesla turns into an oven — and why cracking the windows actually works
The greenhouse effect that heats a closed car cabin, why it happens faster in a Tesla's all-glass roof, and why venting a few inches of window beats almost everything else you can do about it.