Freezer alarm & refrigerator thermometer
The freezer fails at 2am. You find out at 7.
Setpoint watches the temperature in your freezer, fridge or walk-in around the clock and emails you the moment it crosses a threshold you set — while there is still time to save what is inside. No subscription, no cloud account, and no vendor who can switch it off.
Read this before you buy
This is not a plug-and-play consumer thermometer.
Setpoint trades convenience for control. That is the right trade for some people and the wrong one for others, so here is the honest split before you spend anything.
A good fit if…
- You already leave a PC, NAS, mini-PC or Raspberry Pi running.
- You want the readings to stay on your own network.
- You have been burned by a cloud device whose servers were shut down.
- You want history and CSV export without paying monthly for your own data.
- You are logging a restaurant walk-in or back-of-house fridge and already have an always-on machine behind the counter.
Buy something else if…
- You do not keep a computer running 24/7 — the hub is what stores history and fires alerts.
- You want a phone app. There is not one, by design.
- You want it working five minutes out of the box with no setup.
- You need a calibrated, certified instrument for a regulated programme (see below).
Accuracy, honestly
Precise in a fridge. A failure alarm in a freezer.
The DS18B20 probe is not equally accurate across its whole range, and most listings quietly skip that. Refrigerator temperatures sit inside its tight band; freezer temperatures do not.
The ±0.5 °C figure holds from −10 to +85 °C. A domestic freezer runs below that, where the sensor is specified at ±2 °C — comfortably enough to tell you the door was left open or the compressor died, which is what an alarm is for, but not precise enough to be a calibrated record at a −18 °C threshold. If you need that, you need a per-unit calibrated instrument, and we will tell you so rather than sell you this.
What it actually does
Alarm first. Everything else second.
Threshold alarm
Set a high and low limit per probe. Cross it and Setpoint emails you or fires a webhook. The check runs on your hub, so it works with no dashboard open.
History that stays yours
Every reading lands in a local database on your machine, charted over any date range and exportable to CSV or Excel in one click.
Survives the internet
Probe to hub is your LAN. A WAN outage does not stop logging or local alerting — only outbound email needs the internet to leave the building.
Nothing to cancel
No account, no subscription, no telemetry. The firmware is open and the hub app is free, so there is no server to sunset and nothing to brick.
Food service
A logging aid, not a certified instrument.
Continuous electronic temperature logging is accepted and encouraged in food-service practice, and no third-party device certification is mandated for it — the legal duty sits with the operator and the records. Setpoint can support that programme as a temperature-logging aid.
It is not a validated critical-control device, is not certified to EN 12830 or any equivalent standard, and carries no per-unit accredited calibration certificate. It should never be represented as any of those. For vaccine storage, pharmaceutical GxP or accredited cold-chain work, you need per-unit accredited calibration and validated software — this is not that product, and no amount of configuration makes it one.
FAQ
The questions worth asking.
Will it alert me if the freezer fails overnight?
Yes. You set a high threshold and Setpoint emails or webhooks you when the reading crosses it. The check runs on your own hub machine, so it fires whether or not a dashboard is open and whether or not your internet is up — email needs the internet to leave your network, a webhook to a local system does not.
How accurate is it at freezer temperatures?
±0.5 °C between −10 and +85 °C, which covers refrigerator temperatures. Below −10 °C — which includes a typical −18 °C freezer — it is ±2 °C. Enough to tell you the freezer has failed, which is what an alarm is for; not precise enough to be a calibrated record at frozen-storage thresholds.
Does it need a subscription or an account?
No. No account, no subscription, no cloud service. Readings go to a free app you run on your own machine and live in a local database you can export to CSV any time. Nothing phones home, and there is no vendor who can switch it off.
Can I use it for HACCP records?
It can support a HACCP programme as a temperature-logging aid — continuous electronic logging is accepted and no third-party device certification is mandated for food service. It is not a validated critical-control device and is not certified to EN 12830 or any equivalent, so do not represent it as one. The legal duty stays with the operator and the records.
What do I need to run it?
Any Windows or Linux machine you already leave running: a mini-PC, NAS, home server, back-office PC or a Raspberry Pi. That box stores the history and fires the alerts. If you do not already keep a machine on, Setpoint is not the right pick — a cloud thermometer will suit you better, and that is a fine answer.
Is there a phone app?
No. Alerts reach your phone as email or a webhook, and the dashboard is a web page you open in any browser on your network. Nothing to install on a phone, no app-store account.
How many freezers can one hub watch?
Dozens. Probes self-discover on your LAN and each carries its own thresholds, so a whole kitchen or storeroom runs off the one machine you already have. You pay for sensors, not for a gateway.
Get started
Start with the kit.
The DIY kit is the board, the waterproof probe, the charger and a USB-C data cable, with a quick-start card and a one-click browser flasher. You solder it and flash it; the hub app is a free download.