Questions about hot cars
— and HeatSentry

What causes hot car deaths?

Parked vehicles become lethal within 20 to 60 minutes, even on mild days. A closed car absorbs solar energy through its windows — the greenhouse effect — while the metal frame has no efficient way to release that heat. On an 80°F day with windows closed, a car's interior can climb to roughly 125°F within an hour (see the temperature timeline on our Safety Facts page). Inside that environment, a child's core temperature rises 3 to 5 times faster than an adult's because of their smaller mass and less efficient cooling. Once core temperature passes 104°F, organ damage begins; above 107°F, it becomes lethal. The most common pattern is not obvious negligence in the usual sense — 54% of cases happen because a caregiver's routine was disrupted and they believed the child was somewhere else. Stress, a change in schedule, or fatigue compresses attention exactly when memory-based reminders (a stuffed animal on the seat, a phone in the back) are most likely to fail.

How does HeatSentry's alert chain work?

HeatSentry's escalation chain runs in four layers:

1. Detect. Temperature and occupant sensors in the cabin identify dangerous conditions the moment the car is locked — no manual arming required.

2. Alert the driver. HeatSentry sends a push notification, phone call, and SMS to the primary caregiver — simultaneously and persistently. Loud, looping, impossible to dismiss as a one-off notification glitch.

3. Escalate to emergency contacts. If the driver doesn't respond, the chain continues. Spouse, grandparent, neighbor, co-parent — every person you've designated gets the alert.

4. Call for help. Still no response. HeatSentry contacts emergency services (911 in the United States) automatically with the vehicle's last-known location. Someone will always come.

Who is HeatSentry for?

HeatSentry is designed for anyone who carries a vulnerable occupant in a parked vehicle. That includes parents and caregivers of infants and toddlers — 87% of hot car victims are under age 3 and cannot self-rescue; pet owners — hundreds of pets die in hot cars each year per the ASPCA, and dogs regulate body temperature much less efficiently than humans; fleet and daycare operators who run multiple vehicles and need a consistent, accountable safety layer; and RV travelers in regions with extreme summer temperatures who often leave pets or family members onboard during rest stops.

How fast can a parked car become lethal, and on what kind of day?

On an 80°F day with windows closed, a parked car reaches the danger zone in under 20 minutes and can climb to roughly 125°F within an hour, even in partial shade. Heat accumulation is driven primarily by direct solar gain through the windows, not the ambient outdoor temperature — the outdoor thermometer is a weak predictor on its own. Interior temperature is largely a function of exposure time. The full timeline with the bar chart visualization is on our Safety Facts page.

Does HeatSentry require a subscription or app?

No. HeatSentry has no subscription, no monthly fee, and no app you have to remember to open. It is a one-time hardware purchase. Like a smoke detector, it runs in the background automatically — there is no setting to forget, no opt-in flow, and no per-month charge that adds up over years of ownership.

Does HeatSentry work in any vehicle?

Yes. HeatSentry is retrofit-ready — it works with any car seat and any model year vehicle. There is no factory integration required, no specific trim level, and no dependency on a built-in infotainment system. HeatSentry uses cellular connectivity for the alert chain (bundled with the hardware), not Bluetooth — so the chain is not limited by the ~15-foot range that Bluetooth-only devices suffer from. Walk into any building and HeatSentry still reaches your contacts.

What happens if the driver doesn't respond?

The chain does not stop at the driver. If the primary caregiver does not acknowledge the alert within a short window, HeatSentry escalates to the people you've designated as emergency contacts — spouse, grandparent, neighbor, co-parent, anyone with a phone number. Each one receives an SMS, push notification, and call. If no one in the personal-contact chain responds, HeatSentry automatically contacts emergency services (911 in the United States) and provides the vehicle's last-known location. The escalation continues until someone responds.

How is HeatSentry different from existing products?

Three differences matter. First, HeatSentry combines occupant detection (movement, weight, CO2) with temperature — most older products only watch temperature and cannot tell whether anyone is actually inside. Second, HeatSentry uses cellular connectivity, so the alert chain is not limited by Bluetooth range. Third, HeatSentry's escalation chain does not stop at a single person; if one contact misses the alert, it cascades to the next. Existing products tend to fail in three predictable ways: alerting only one person, monitoring only temperature, and dropping the connection the moment the driver walks away.

Where does your data come from?

Every statistic on HeatSentry's pages traces back to a primary public source. Annual US child heatstroke death counts and state-by-state breakdowns come from NoHeatStroke.org (maintained by San Angelo State University under Jan Null). Broader child-vehicle safety incident tracking comes from Kids and Cars. Federal vehicle-safety research, including caregiver-attention studies, comes from NHTSA. The clinical figures for children's heat absorption (3–5× faster than adults) come from the American Academy of Pediatrics. Pet heatstroke prevalence and the 104°F organ-damage threshold come from the ASPCA's hot-weather safety guidance. See the full sources list →

How can organizations partner with HeatSentry?

HeatSentry is exploring pilot partnerships with daycare chains, fleet operators, pediatric offices, and animal-welfare organizations. Daycare and fleet operators can join the waitlist using the Use Case dropdown set to "Fleet Operator / Daycare" — we'll reach out to coordinate pilot deployment. ASPCA-style partner channels, pediatric networks, and other organizations interested in co-marketing or distribution can reach us directly at heatsentry-os@polsia.app. For broader context on our partnership framing, see the About page.

Is HeatSentry available now?

HeatSentry is currently in pre-launch and accepting waitlist signups. Join the waitlist on the home page and we will notify you as soon as HeatSentry ships to your area.

Is HeatSentry a subscription product?

No. HeatSentry is explicitly a one-time hardware purchase — there is no $12.50/month subscription, no app-store premium tier, no annual fee. You buy the device once, pair it with your emergency contacts, and it runs automatically in the background for the life of the hardware. Cellular connectivity for the alert chain is bundled with the hardware, not billed separately.