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RADON411

SafetySiren

SafetySiren Pro4

Plug-in radon detector with a display and alarm

  • Monitor
  • Plug-in
  • Screen
  • First reading in 48 hours
C-NRPP 2024/25 evaluation: Not includedSee the evidence
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  • PowerPlug-in
  • ReadingsScreen
  • First reading48 hours
  • C-NRPP 2024/25Not included
  • Every figure checked against the specifications SafetySiren publishes
  • Independent test results shown the same way for every product, unranked
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About this item

As SafetySiren states it

  • How it measures: Diffused-junction photodiode sensor (250 V DC); samples the air passing through its ventilation slots
  • First reading: Within 48 hours
  • Reading updates: Every hour; short-term rolling average over the past 48 to 168 hours, long-term rolling average up to 365 days
  • Display and app: Built-in display
  • Power: Plug-in: Plugs into a standard 120-volt household outlet with the supplied power cord; 100-240 V switching power supply, detector input 5.0 V, 1.0 A max
  • Units: pCi/L or Bq/m³, fixed by the model purchased

The SafetySiren Pro4 Series is a plug-in radon detector from Family Safety Products of Grandville, Michigan: a diffused-junction photodiode sensor, a display with short-term and long-term averages that update every hour, and an 85 dB alarm that chirps when radon stays at the preset action level. Its first reading takes 48 hours. It was not included in C-NRPP's 2024/25 evaluation, so there is no independent result for it either way.

What you get

The manual mentions the supplied power cord, with a 100 to 240 V switching power supply that feeds the detector 5.0 V at up to 1.0 A, but it does not list the package contents, so they are not stated by the maker. The detector measures 4 5/8 by 3 3/8 by 2 inches. Its serial number and maker information are on a label on the underside, and one screen shows the model number and firmware version.

In the box and running costs

How it works

What it measures and how

The sensor, the sampling and the readings, then who has checked it

How it works

In our words, from the maker's documents

Family Safety Products lists the sensor as a state-of-the-art diffused-junction photodiode, run at 250 V DC. The detector reads the room air that passes through its ventilation slots: the manual says a proper airflow must be kept through the detector to get an air sample representative of the room, and that the detector must be kept dust free.

When it is first plugged in, the display shows CAL with running dashes for about a minute while the detector runs a self-test and calibrates to its surroundings, and the alarm sounds four beeps. The radon readings then show two dashes until enough samples are in: the manual says samples are taken for 2 days (48 hours) before an accurate reading can be displayed, and a shield icon blinks through those first 48 hours. It asks you to treat the first 48-hour average as an indication only, because radon varies from day to day and season to season.

The home screen shows two averages. The short-term figure covers the past 48 to 168 hours, at most 7 days; the long-term figure covers the time since the detector was powered up or its memory last cleared, up to 365 days. Both are rolling averages, and both update once an hour. A second screen shows how long each has been running, in hours for the short term and days for the long term.

Each detector shows one unit, fixed by the model: pCi/L or Bq/m³. The pCi/L model reads from 0.0 to 9999.9. A single menu button steps through six screens; the first tap lights the display, the backlight goes off after 25 seconds without a press, and the display returns to the home screen after 15 seconds. The detector repeats its self-test every 24 hours and flashes a wrench icon with an error code if one fails.

When the detector reaches its alarm state, preset by the manufacturer, the buzzer sounds 4 short chirps and repeats them every hour until the level drops below the action level or you mute it, while a warning icon flashes beside the high reading. It alarms on the long-term average at or above the action level once the first 168 hours have passed, or on the short-term average at or above it for 30 consecutive days. The menu offers two mute settings, OFF30 and OFF90, and a test mode that sounds the alarm on demand.

What the manufacturer says

SafetySiren's own statements, attributed

  • SafetySiren saysFamily Safety Products lists accuracy and precision at 25 pCi/L, typical, as within 12% at 7 days and within 5% at 1 month.
  • SafetySiren saysFamily Safety Products rates the audible alarm at 85 dB at 10 cm and says the user can mute it.
  • SafetySiren saysFamily Safety Products states that the SafetySiren model you buy determines which predefined action level is preset in the detector, and lists the US EPA's 4.0 pCi/L among them.
  • SafetySiren saysFamily Safety Products describes the detector as made in the USA.
  • SafetySiren saysFamily Safety Products gives a one-year limited warranty to the original retail purchaser.

These are SafetySiren's own statements, attributed to it. They are not our findings, and we have not tested this product ourselves.

Independent evidence

C-NRPP 2024/25, recalls and studies

C-NRPP 2024/25
Not included in C-NRPP's 2024/25 evaluation

The Canadian National Radon Proficiency Program's 2024/25 comparison of consumer monitors did not include SafetySiren Pro4. That is a fact about which devices took part, not a finding about this one: no result from that program exists for it either way.

Recalls
No Health Canada recall or advisory names this device.
Peer-reviewed studies
We found no peer-reviewed comparison that names this model.
Notes
  • No Health Canada recall or advisory (radon search, seven notices), no CPSC recall, and no row of C-NRPP's consumer page or 2024/25 report names SafetySiren, Family Safety Products or a Pro4 (checked 2026-10-08).

C-NRPP is the Canadian National Radon Proficiency Program. Its 2024/25 results were published in May 2025.

Specifications

Specifications

Every figure as the maker states it

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The maker's figures

Type
Continuous monitor, plug-in, display with short-term and long-term averages, 85 dB alarm, photodiode sensor
How it measures
Diffused-junction photodiode sensor (250 V DC); samples the air passing through its ventilation slots
First reading
Within 48 hours
Reading updates
Every hour; short-term rolling average over the past 48 to 168 hours, long-term rolling average up to 365 days
Display and app
Built-in display
Power
Plug-in: Plugs into a standard 120-volt household outlet with the supplied power cord; 100-240 V switching power supply, detector input 5.0 V, 1.0 A max
Units
pCi/L or Bq/m³, fixed by the model purchased

What is in the box

The manual mentions the supplied power cord, with a 100 to 240 V switching power supply that feeds the detector 5.0 V at up to 1.0 A, but it does not list the package contents, so they are not stated by the maker. The detector measures 4 5/8 by 3 3/8 by 2 inches. Its serial number and maker information are on a label on the underside, and one screen shows the model number and firmware version.

The warranty is a one-year limited warranty to the original retail purchaser, not transferable, from the date of retail purchase; a unit found defective within it is repaired or replaced free of charge. A return needs a return authorization (RA) number from Family Safety Products and a copy of the original purchase receipt. The warranty does not cover the cost of shipping the product to Family Safety Products, normal wear, damage from misuse or tampering, including removing the back cover, or damage from not following the manual.

What it costs to run

There is no lab fee, subscription, app or battery: the Pro4 runs from a wall outlet through its power supply. Family Safety Products publishes no sensor lifespan, calibration service or replacement schedule in the manual, so those are not stated by the maker. C-NRPP notes that consumer radon monitors cannot be professionally calibrated.

Warranty service, by the manual, goes through Family Safety Products in Grandville, Michigan, by phone, email or mail with a return authorization number, and shipping the detector to them is at your cost. The manual's pages are dated 2020, so ask the seller who handles warranty claims now before you buy.

Fit and setup

Who it fits, and how to use it

The fit, then setup and placement as the guidance asks

Who it fits

Good fit if, and look elsewhere if

Good fit if

  • You want a plug-in detector that sits on a table and sounds its alarm in the room.
  • You want short-term and long-term averages on the display, with no app or account.
  • You want the alarm to follow the averages, so a single high day does not set it off.
  • You want a self-test every 24 hours with an error shown on the screen if it fails.

Look elsewhere if

  • You want a monitor whose own model was graded in C-NRPP's 2024/25 evaluation; the Pro4 was not included.
  • You want to set your own alarm level; the Pro4's is preset by the manufacturer for the model you buy.
  • You want a first number within minutes or hours; the Pro4 samples for 48 hours before its first reading.
  • You need a result for a home sale; check what your state accepts before relying on any consumer monitor.

Setup and placement

5 steps

  1. Family Safety Products' manual says to place the detector in the lowest lived-in level of the home, the basement if it is used frequently and otherwise the first floor, in a room used regularly such as a family room, bedroom or den but not the kitchen or bathroom, at least 20 inches above the floor, and where its alarm can be heard from the areas you use every day. It is for indoor use only.
  2. Keep it at least 5 feet from drafts from heating, ventilating and air conditioning vents, fans, and windows or doors to the outside, away from excessive heat such as fireplaces and direct sunlight, and out of humid rooms such as bathrooms, kitchens and laundry rooms. It plugs into a standard 120-volt household outlet with the supplied power cord and sits face-up on a tabletop, countertop or other flat surface where its ventilation slots are not blocked. The manual warns against an outlet controlled by a light switch, and gives an operating range of 41°F to 104°F (5°C to 40°C).
  3. When you move it, the manual says to clear the memory, which returns personal settings to factory settings, sounds four chirps, runs a self-test and starts the 48-hour sampling again. Clean it with a dry cloth, and do not remove the back cover: the sensor runs at 250 V DC, and removing the cover voids the warranty.
  4. The EPA's general guidance for any home radon test agrees with the manual on the lowest lived-in level, a regularly used room and 20 inches above the floor, and adds away from drafts, high heat, high humidity and exterior walls. The EPA says to fix the home at 4 pCi/L or more and to consider fixing between 2 and 4 pCi/L.
  5. C-NRPP's advice for any consumer monitor is to place it in a room occupied at least 4 hours a day, test for a minimum of 3 months, preferably in the heating season, and decide on the long-term average, following up with a long-term test if you have less than 91 days of data. On the Pro4 that figure is the long-term average on the home screen.

How C-NRPP says to use any consumer monitor

  • Leave it in place for at least three months, ideally through the heating season, when indoor radon tends to be highest.
  • Put it in a room someone uses for at least four hours a day.
  • Decide about fixing your home from the long-term average, not a single day or week.
  • If you can only run a monitor for less than 91 days, follow up with a long-term test.

For where any radon test or monitor should sit in a home, see where to place a radon test.

Compare

Compare with similar items

The same three rows for each, and the one difference that matters

Compare side by side

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Questions

Questions people ask

6 questions about the SafetySiren Pro4, answered

Asked about the Pro4

How long before the Pro4 shows a radon reading?

Two days. The manual says samples are taken for 48 hours before an accurate reading is displayed; until then the readings show two dashes and a shield icon blinks. After that the averages update every hour, and the manual asks you to read the first 48-hour figure as an indication only.

When does the alarm sound?

When the detector reaches its preset alarm state: the long-term average at or above the action level after the first 168 hours, or the short-term average at or above it for 30 consecutive days. The buzzer then gives 4 short chirps every hour until the level falls below the action level or you mute it. The manual says the model you buy determines which action level is preset, and lists the US EPA's 4.0 pCi/L among them.

Can I silence the alarm?

Yes, for a while. Holding the menu button on the alarm screen chooses between the alarm on and two mute settings, OFF30 and OFF90. A mute icon then shows at the top of the screen, and the detector counts down the days until the alarm switches back on.

Does the Pro4 run on batteries?

No. The manual describes a detector that plugs into a standard 120-volt household outlet with the supplied power cord, and it mentions no battery. Unplugging it and plugging it back in is also how the manual has you power-cycle it after an error message.

Does it show pCi/L or Bq/m³?

One or the other, fixed by the model: the manual says the display unit is a fixed feature that depends on the model purchased. The pCi/L model reads from 0.0 to 9999.9 pCi/L.

Is the SafetySiren Pro4 C-NRPP approved?

It was not included in C-NRPP's 2024/25 consumer monitor evaluation, so there is no C-NRPP result for it either way.

What to do next

Updated October 8, 2026