Can I get a freeze alarm without a monthly subscription?
Yes. Temp Stick sells finished sensors ($149 and up) with free text, email, and app alerts. Govee's Wi-Fi sensors (about $35–50 with the gateway) send app alerts. Home Assistant is free if you run it yourself, and ProbeHarbor's free plan sends email and chat alerts from a DIY sensor. SMS on ProbeHarbor needs the Pro plan.
The options
Temp Stick: a finished battery Wi-Fi sensor. The most expensive per sensor, but no setup and no fees, and it includes text alerts.
Govee: cheap Wi-Fi gateway plus sensors with app notifications. Fine for a room; check that alerts reach you reliably away from home.
Home Assistant: free and flexible if you already run it, but it depends on your home internet and power staying up (see the Home Assistant freeze alert answer).
ProbeHarbor: about $25 of DIY parts per probe, free email, chat, and push alerts, leak contacts, and history. SMS and longer history are on paid plans.
What to weigh
Setup: finished sensors win. Cost per zone: DIY probes win once you want several. Getting woken up at night: SMS or push matters more than email, so check which plan includes it.
Frequently asked questions
Does Temp Stick charge a monthly fee?
No. Temp Stick says monitoring, data history, and text, email, and app alerts are free for the life of the sensor.
Is ProbeHarbor free?
There is a free plan with email and chat alerts, a week of history, and up to two devices. Member and Pro add history, CSV export, forecast warnings, and SMS.
Related
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Get a freeze alert for your space
ProbeHarbor watches probes in garages, crawlspaces, and cabins and alerts you before pipes freeze. The free plan includes email alerts; bring an ESP32 probe or connect Home Assistant.