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RADON411

Forensics Detectors

Forensics Detectors FD-65-RADON

Rechargeable radon detector with a color screen

  • Monitor
  • Battery
  • Screen
  • First reading in 6 hours
C-NRPP 2024/25 evaluation: Not includedSee the evidence
  • Forensics Detectors FD-65-RADON
  • Forensics Detectors FD-65-RADON, photo 2 of 4
  • Forensics Detectors FD-65-RADON, photo 3 of 4
  • Forensics Detectors FD-65-RADON, photo 4 of 4

Photos: Forensics Detectors

  • PowerBattery
  • ReadingsScreen
  • First reading6 hours
  • C-NRPP 2024/25Not included
  • Every figure checked against the specifications Forensics Detectors publishes
  • Independent test results shown the same way for every product, unranked
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About this item

As Forensics Detectors states it

  • How it measures: Alpha-decay event detector with a radon semiconductor sensor; natural diffusion, no pump
  • First reading: Within 6 hours
  • Reading updates: Every hour, showing the latest 6-hour average
  • Display and app: Built-in display
  • Power: Battery: Built-in 3.7 V 2000 mAh lithium-ion battery, USB Type-C charging; 45 days of operation
  • Units: pCi/L, or Bq/m³ set in the menu

The FD-65-RADON is a pocket-sized radon detector from Forensics Detectors, a California maker of gas detectors: a semiconductor sensor that counts alpha decay by natural diffusion, a 2-inch color screen, an alarm, and a built-in battery charged over USB-C. It was not included in C-NRPP's 2024/25 evaluation.

What you get

Forensics Detectors lists the radon detector, a user manual and a USB Type-C recharge cable in the box; the manual asks for a charger rated above 1.0 A for fast charging. It measures 3.2 by 1.6 inches and weighs 4.3 oz. The warranty is a one-year limited warranty, and the manual says the unit cannot be repaired if it has been tampered with.

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

Forensics Detectors describes the sensor as an alpha-decay event detector with a radon semiconductor sensor. Air reaches it by natural diffusion, with no pump, and the sensor registers the alpha particles given off as radon decays. The screen keeps a running total count, and a green light on the front flashes once each time an alpha decay is detected, so you can see it working.

The first reading takes 6 hours after the detector is switched on. The manual explains why: alpha decays are infrequent at ordinary indoor levels, radon has to diffuse into the chamber and reach equilibrium, and the detector integrates the signal over time to smooth out random swings. After that, the main reading updates every hour and shows the average of the latest 6 hours.

Beside the 6-hour value, the detector cycles through 12, 24, 48 and 96-hour averages and an accumulated average and peak since it was switched on, and it logs the 6-hour average with the accumulated average and peak, each stamped with the time and date. Forensics Detectors lists a reaction range of 0.09 to 1000 pCi/L, or 3.3 to 37,000 Bq/m³, and an accuracy of ±15%.

Readings show in pCi/L by default, and the settings menu switches the unit to Bq/m³. The same menu sets the low and high alarm points, a screen sleep mode to save power, the language and the clock. When the reading passes the limit, the value flashes with an alarm icon and a 75 dB ticking sounds for 20 seconds every hour.

Power is a built-in 3.7 V, 2000 mAh lithium-ion battery, which Forensics Detectors rates for 45 days of operation and charges over USB Type-C in about 4 hours. An animated battery icon shows while it charges, and "Charging Complete" appears when it is done; the readings and the log are read on the device's own screen.

What the manufacturer says

Forensics Detectors's own statements, attributed

  • Forensics Detectors saysForensics Detectors states a sensor life of more than 20 years.
  • Forensics Detectors saysForensics Detectors lists a reaction range of 0.09 to 1000 pCi/L and an accuracy of ±15%.
  • Forensics Detectors saysForensics Detectors states the ABS housing can take a 10 ft drop.
  • Forensics Detectors saysForensics Detectors states 45 days of operation on a charge and a charging time of about 4 hours.
  • Forensics Detectors saysForensics Detectors gives a one-year limited warranty.

These are Forensics Detectors'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 Forensics Detectors FD-65-RADON. 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
  • Re-read C-NRPP's page on 2026-10-06 (products-probe run 38-1): no Forensics Detectors device is listed, approved or not approved, and Health Canada's radon recall list (same run) names none.

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

Compare side by side

The maker's figures

Type
Continuous monitor, rechargeable, color display, semiconductor sensor
How it measures
Alpha-decay event detector with a radon semiconductor sensor; natural diffusion, no pump
First reading
Within 6 hours
Reading updates
Every hour, showing the latest 6-hour average
Display and app
Built-in display
Power
Battery: Built-in 3.7 V 2000 mAh lithium-ion battery, USB Type-C charging; 45 days of operation
Units
pCi/L, or Bq/m³ set in the menu

What is in the box

Forensics Detectors lists the radon detector, a user manual and a USB Type-C recharge cable in the box; the manual asks for a charger rated above 1.0 A for fast charging. It measures 3.2 by 1.6 inches and weighs 4.3 oz. The warranty is a one-year limited warranty, and the manual says the unit cannot be repaired if it has been tampered with.

What it costs to run

There is no lab fee or battery to buy: the lithium-ion battery is recharged over USB-C, about every 45 days by Forensics Detectors' rating, from a 5 V charger rated above 1.0 A. Forensics Detectors states a sensor life of more than 20 years.

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 small detector to carry from room to room or to a rental.
  • You want a number on the screen within hours, with an alarm when it passes your limit.
  • You want a rechargeable battery instead of disposable cells.
  • You want a time-stamped log on the device without an app.

Look elsewhere if

  • You want a device that was itself graded in C-NRPP's 2024/25 evaluation.
  • You want a first number within minutes; the first reading takes 6 hours.
  • You want a warranty longer than one year.
  • You need a result for a home sale; check what your state accepts before relying on any consumer detector.

Setup and placement

4 steps

  1. Hold the power button for 3 seconds to switch it on, then leave it for the 6 hours it needs to gather data. Forensics Detectors' manual says to place it in the lowest lived-in level of the home, at least 20 inches above the floor, away from exterior walls, drafts, high humidity and electronic devices, and to avoid large vibration while it measures.
  2. The EPA's general placement guidance says the same about the lowest lived-in level, 20 inches and drafts, and adds a room used regularly but not the kitchen or bathroom. Forensics Detectors lists operating and storage conditions of 14 to 122°F and below 90% relative humidity.
  3. To start a new average, use Retest in the menu, which begins new averaging data. After a very high reading, the manual notes the detector can hold residual radon for 1 to 4 days and recommends waiting 24 to 48 hours before reading the measurements again.
  4. For a decision about fixing your home, 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. With less than 91 days of data, it recommends a follow-up long-term test. The EPA's guidance is to fix a home at 4 pCi/L or more and to consider fixing between 2 and 4 pCi/L.

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

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Questions

Questions people ask

5 questions about the Forensics Detectors FD-65-RADON, answered

Asked about the FD-65-RADON

How long does the FD-65-RADON take to show a reading?

6 hours after it is switched on. After that the reading updates every hour with the latest 6-hour average, and the 12, 24, 48 and 96-hour and accumulated averages build up behind it.

Can it show Bq/m³ instead of pCi/L?

Yes. It shows pCi/L by default, and the Unit setting in the menu changes it to Bq/m³.

How long does the battery last?

Forensics Detectors rates the built-in 2000 mAh lithium-ion battery for 45 days of operation and gives a charging time of about 4 hours over USB Type-C. The Eco setting puts the screen to sleep to save power.

Is the FD-65-RADON 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 happens when the radon level is high?

Once the reading passes the alarm point you set, the value flashes with an alarm icon, the front light flashes red and a 75 dB ticking sounds for 20 seconds every hour. The manual's own advice for a high level is to contact a certified radon mitigation specialist.

What to do next

Updated October 6, 2026