When we go out to give an estimate to people who are selling their home, there are usually a couple of frequently asked questions...
Why does my house (but not my neighbor's) have radon?
How does a radon mitigation system work?
Why must the system reach beyond the house?
For houses with slabs, do you drill a hole? Where do you drill?
Why do fans have to be outside or in the attic?
How much does system maintenance cost?
Is there any difference between interior and exterior installation?
Do ceiling fans and humidifiers help to reduce Radon?
While viewing the house, usually we start in the basement by looking for holes and gaps, and we'll talk about the radon passages - where it's coming from and why it accumulates in your house. Often we draw a sketch of the house and how air moves up from the soil and becomes trapped by the huge surface area that your house occupies.
The process where this air pressure (and Radon) finds a release point into the house is called depressurization: air moves where there is the least resistance and where there's a vacuum. That's why a radon mitigation system is often called a sub-slab depressurization system.
Next, people want to know: how dangerous is Radon really?
Well, the fact is that radon is the second leading cause for lung cancer. The radiation of alpha particles in Radon are ten times stronger than x-rays!! And when a person is inside the house for many hours, working out in the basement, breathing in concentrated Radon in the air, they can experience a radiation charge, that although minimal, can destroy lung cells. Then, when the body regenerates and reproduces lung cells, many things can go wrong and that's where cancer cell growth occurs.
That being said, a lot of people panic about radon levels even if they are not significantly elevated. Some people won't buy a house until Radon is reduced to comfortable levels. It's important to remember that there are many other cancer causing agents to consider. Cancer is a very complex reaction in your body and other factors like chemicals, environmental hazards, fumes that we are so used to, food, exercise, our psyche…. everything plays a role. We like to spread the information a bit wider and not focus exclusively on radon regarding lung cancer. Our advice is always to open or crack the window for fresh air, and movement, as much as possible. For example, just a window cracked open for an inch or two can reduce radon levels in your home to a very safe level.
For some people radon is not a health concern, but they just wonder why their house has radon and the neighbor’s does not?
Here's how it happens: there is movement of air in the soil. You can have certain areas where air gathers, and that pocket might be just under your house and not the neighbors. And the only way to find out is through testing. There are different types of testing equipment: active and passive, the cheapest of which is the charcoal activated tests (from Lowe's, for example), and the most expensive being the radon monitor, which is a Geiger counter that actively analyzes the air for radon content. It measures every hour and calculates an average at the end of the testing period. This technology allows for exact measurements that only have a variation of 3 to 5% , whereas the charcoal canister can vary up to 25%, so you get what you pay for. With a charcoal test you will not be able to see the highs and lows shown by the hourly readings of the monitor, so the passive sample test can only absorb so much and usually reflects the last 8 hours of testing only.
Then the people want to know: how does a system work?
As explained earlier, we de-pressurize the soil or the sub slab by creating a vacuum and pulling the air towards the pipe. A Radon fan actively creates the vacuum and forces air to move into the system. Once there, it will be drawn away, above and beyond the house.
And that is the next question: what does the fan do?
The fan is the active part in that system, and there are different types of fans that can draw a lot of air by volume.
Why does the system have to reach beyond the house?
Because wind and air movements can bring the Radon gas back into the house through an open window.
(Sometimes...) We have a situation with high Radon levels in a slab-on-grade-house (there is no basement or crawlspace). Do you have to drill a hole in the slab? Where would you do that?
Good question! This is a common situation. Very often we access the sub-slab aggregate (the gravel layer beneath the floor) from outside. By drilling through the footer, below the floor level, we can access the gravel layer and install a pipe and fan. All this is done without going into the house. From inside, we have to find a closet or utility space where a suction hole and pipe can fit.
Are the fans noisy?
No, they are not typically noisy. In fact, they're usually quieter than the outdoor AC unit. We make it a point to install the fan away from bedrooms whenever possible. What you may sometimes hear is just the airflow through the pipe. If feasible, we place the fan in the attic, outside, or above the garage to further minimize any noise.
Why does a fan have to be outside or in the attic?
Because the rubber couplings that are connected to the fan may dry rot and leak, and nobody will notice it. So therefore, it's safer to have the fans outside or in the attic above living spaces.
Is it possible that a fan can draw from the ground surrounding the house and into the basement, actually increasing the radon levels?
The house has a footer that is 2ft. deeper, a foundation, and the fans are not that strong! They create a vacuum at the spot below the slab, which allows air to move towards it, but they are not powerful enough to draw Radon in from the perimeter outside the house and penetrate the footer.
What about costs and maintenance?
There is no maintenance to the system, except for regular testing every three to five years. The electrical bill is that of a 75 Watt light bulb. There's a visual design, the manometer in the basement, which tells you that the system is working. This shows the airflow (not a measurement of Radon).
90% of the fans that were installed 15 years ago are still running today. They are very reliable. We use fans exclusively from one company; their products and customer service are outstanding.
Is there any difference between interior and exterior installation?
The price tag! Interior installations are more labor-intensive and therefore more costly. For example, if you are hiding the pipe in a closet, the holes in each board will need to be cut so they lineup perfectly with the one above and below. Holes will be needed in the floor (hardwood or carpet) and the ceiling on each story, and will need to fit precisely. The roof will need to have proper flashing.
The advantage? The system completely disappears (except for the exhaust vent). The interior installation adds to the resale value of the house in the future.
Do ceiling fans and humidifiers help to reduce Radon in your home?
No, they don't and even your sophisticated and expensive air filters cannot filter out Radon gas. They are ineffective in reducing Radon.
What is the cost of the system?
Installing a complete radon reduction system typically costs between $1,100 and $1,400, including re-testing. This is a one-time investment that provides peace of mind for a lifetime. Once installed, you won’t have to worry about Radon again. If you decide to sell your home in the future, having a Radon mitigation system can make your property more attractive to buyers, especially compared to homes without one. With growing awareness about Radon risks, many people are hesitant to purchase homes with high Radon levels. Installing the system now allows you to enjoy a healthier living environment and adds value to your home when it’s time to sell.