Pro4 Series (4th Gen) - Leader in Home Radon Detection Since 1993. Made in The USA - USA Version pCi/L

The SafetySiren Pro4 is a reliable and easy-to-use radon detector that provides continuous monitoring for long-term exposure risks. Setup was straightforward, and within a few hours, it started displaying accurate radon level readings. I appreciate the clear digital display and the built-in audible alarm, which alerts if radon levels rise above safe limits. Since radon is a serious health hazard, having a trustworthy detector is essential, and this unit gives peace of mind. If you’re looking for an affordable, USA-made radon detector, this is one of the best options available.

The radon detector was received in the time expected and in a bubble envelope. It is winter and the unit was allowed to warm to room temperature. Next, it was plugged into the wall outlet. An error message appeared upon initialization. Per instructions, electric power to the unit was cycled. This time the unit came up with the correct response - beeps, flashing CAL, then dashed lines for short term and long term readings in pCi/L. Per instructions, readings appeared in place of the dashed lines in 48 hours. I had placed the device in a bedroom of the house on the second floor. The initial readings were 1.8 pCi/L. This is close to one-half of the EPA action limit of 4.0 pCi/L or 148 Bq/m^3. (Each 1 pCi/L is equal to 37 Bq/m^3.) The WHO states that 2.7 pCi/L or 100 Bq/m^3 is the action level. The WHO also states that lung cancer risk will increase by 16% for every 100 Bq/m^3 of long term exposure. It is also important to remember that cancer risk is based on long-term exposure. It does not matter if the exposure was continuous or intermittent. Exposure to radon adds up over time. If you have moved from one house to another, each new exposure adds to long-term exposure. After 7 days of monitoring the radon reading fell to 1.7 pCi/L. We fully expected that the readings in our house would increase when we moved the sensor to the first floor and then to the basement. After 6 days of monitoring of the first floor near the kitchen and laundry the reading was 1.9 pCi/L. A week later the reading had fallen to 1.0 pCi/L. Thinking that there might be something wrong, we continued to monitor the reading for another week, and it steadily climbed to a maximum value of 2.5 pCi/L. That reading persisted for 3 days, and it is steadily falling again. These results show why long term monitoring is important. It is winter and the ground is beginning to freeze, although there is no snow cover. This makes the ground more, not less, permeable to radon gas. If it rains or snows, the ground becomes less permeable to radon and the gas may be less apt to dissipate into the outside air and more apt to enter the basement. The most common point of entry is the basement, but radon can also enter through windows and doors. The water content of the soil around the house, how well the basement windows are sealed, how well the basement concrete cracks and seams are sealed and concrete porosity all contribute to basement radon levels. Radon levels (if you have well water) will usually increase in the winter in a closed house where water vapor releases radon gas from laundry, dishwasher and bathing. The contribution due to evaporation of radon laden well water is added to the contribution entering the home from the basement to get the radon total. That is what is being read on the first and second floors of our home. Readings in the basement will be due to infiltration of radon through cracks in the foundation and basement slab as well as the porosity of the concrete, itself. Our well water contains nearly 4,000 pCi/L of dissolved radon. That is less than half the EPA actionable level of 10,000 pCi/L. Every 10,000 pCi/L of dissolved radon is expected to add 1.0 pCi/L to the air in the house due to dish washing, laundering and showering. We have no direct way of knowing if an additional 0.4 pCi/L has been added due to water vapor. We can assume, however that part of the dissolved radon in our well water is removed by the charcoal filter on our domestic well water supply. There is one additional note that might be added. There is no battery backup power to the unit. However, when the detector is moved to a new location, the data from the previous location will be held until the reset command is asserted with the push button on the face of the device. We have been very happy with the functionality of this device and will use it to guide us in radon mitigation decision making in the spring. If interested, the instruction manual with specifications can be found online. The manual provides sensor accuracy specifications for short and long term measurements. This is not a professional, periodically calibrated instrument. However, the accuracy should be more than adequate for determining when to call a professional. Added note, it is spring and the ground has thawed and heaved. The ground floor radon readings for the last two weeks have been between 2.2 and 2.7 pCi/L. We also have 135 days of data for our ground floor living space and the average is 2.0 pCi/L. Currently, the sensor is monitoring the basement so that a radon fan can be sized in cubic feet per minute (CFM). The bigger the fan, the more electricity it will use on a continuous basis. Most fans use between 50 and 100W. In this locale electric power is $0.20 per kW-hour. The annual operating cost would be between $88 and $175.Update: After this review was written, we installed a radon fan in our passive radon stack. Then, we caulked all of the basement slab cracks, expansion joints and basement floor-wall joints with a high quality radon caulk to improve the vacuum under the basement slab and to reduce heat loss. We also caulked around all of the basement bottom plates because there are anchors in the bottom plates that penetrate the concrete. (If you don't caulk, the radon fan will pull conditioned air right out of the house and send it up the radon stack, so please do it.) The radon level, year-round, has dropped to 1 pCi/l or less at the point in the basement room that is farthest from the radon suction point in the basement slab. In order to increase the confidence level of the measurement, we placed an Airthings Corentium Home battery operated unit near the Pro4. Although they employ different sensors and algorithms, there is good correlation between the two, and that increases our confidence level in the measurements. We purchased largest, adjustable speed Fantech radon fan that we could find, and we run it at very slow RPM. It is capable of moving a huge volume of air when turning slowly. It employs a massive Pabst fan with excellent bearings. The fan draws barely 250 mA on 115 VAC as measured with a clip-on current probe. That's 28.75 Watts. It is hardly noticeable in our monthly electric bill, maybe $3.50.

I am not sure if it was used before I got it or it was tested and not reset before packaging. When I first turned it on there were values displayed indicating high radon. After resetting it seems to be working as expected. I had a radon mitigation fan installed in our basement and wanted to be sure it was working properly. I trust the accuracy but can only compare it to the values the radon mitigation installer showed me when he left his meter for several days after the installation. An inexpensive insurance policy to ensure my family is not poisoned by radon. We live in a high radon area.

I like that the set up was very easy, and (hopefully) it’s giving us an accurate reading. The reason I took off one star is because it doesn’t plug directly into an outlet. It has a cord (wire) instead, so, you have to have it on a table or other platform unless you want to put it on the floor.

These are pretty basic compared with other monitors, but Canadian comparative control tests show them to be accurate over time. We have two. Both are showing similar results. Both are measuring higher than another popular web enabled instrument. I trust them.

You might be tempted to buy a cheaper radon monitor but this one is worth the money. it is AC powered so there is no issue with battery leakage destroying it. It has a stable short-term reading day-to-day unlike the cheap battery powered airthings units. The readings are saved when the power goes out too so your long-term reading doesnt have to start over.

After reading about it being the leader in home radon detection since 1993, I felt pretty good buying this one. Also reading the comments, that were super helpful with reviews on its accuracy etc, also helped me to buy this unit over others. We recently added a home theater to our finished basement just before Thanksgiving and have since been spending about half of our time down there. My mother had told me about radon gas when I was growing up and she had encountered it and questions about it as a realtor. I remembered this and wanted to be sure it was safe in our basement with us being down there so much now days. We followed instructions in the booklet provided and got results as it stated. Happy we are within safe measurements and can rest easy spending so much time down there ourselves, as well as having family and friends over as well. The peace of mind is worth the money for something like this, as a lot of people don't even know about radon gas, let alone the dangers/risks of it. I'd highly recommend this unit to anyone and have in my personal life!

I use this to keep track of the Radon in my basement. Seem to work very good.