Radon, Radioactivity, and Lung Cancer - Get A Test
If you have a basement and you spend time there - test for radon. Radon causes lung cancer and kills 21,000 people every year in the USA alone.
So you’ve calculated that air sealing your house may be one of the most cost-effective upgrades you can make to lower your bills and be more comfortable. Before you start air-sealing, however, there is something you should check first: radon.
Radon
Radon is a radioactive, colorless, odorless, tasteless gas. It can be present anywhere in the earth’s crust - anywhere humans dig into the dirt. For example: when digging a basement to build a house. And it can cause lung cancer.
If you have a basement, and you spend time there, you should test for radon.☢️
The Environmental Protection Agency estimates that radon causes 21,000 deaths from lung cancer each year. It’s second only to cigarette smoking. Radon levels can vary a lot from place to place - even (apparently) within the same neighbourhood. But if you have a basement, you should at least do a test.
Urgent Fixing Levels Of Radon
Different countries publish different levels for radon remediation:
USA: Fix if above 150 units, or 4 pCi/L.
The USA uses pCi/L (usually numbers from 0 to 50), while the rest of the world uses Bq/m3 (usually numbers from 0 to 1,000).
To convert to/from each unit - just multiply or divide by 37
Europe: 200 to 400 units (5 pCi/L)
WHO / Norway: 100 units (2.7 pCi/L)
Surprisingly the AirThings help docs have this useful collection of rules and levels from various countries.
However - higher tolerance levels mainly seem to be based on how much political will exists to fix or discuss radon. Countries claiming that higher levels are still “safe” has nothing to do with studies or results on how much radon is harmful or dangerous.
There Is No “Safe” Level Of Radon - Always Test
Many sources note:
“There is no known *safe* level of exposure to radon.”
Background levels of radon outdoors in nature are cited around 15 to 40 units - 0.4 to 1.1 pCi/L. Reducing below this may be difficult and probably not necessary. But reducing your home to be as healthy as you can seems worth the investment.
If you run a test and discover you need to reduce or fix your radon level - fix it to be as low as you can.
How To Test For Radon
There are at least two types of tests - short-term and long-term.
A short-term test can usually be done with an air-quality monitoring tool, such as Airthings (disclaimer: I own one of these). Usually you leave the tool sitting in your house for several weeks.
Your local library may be able to loan you a short-term test device. Go check!
A long-term test is done with a special radon capturing and sensing device, that is sent to a specialized lab for analysis. These usually sit in your home for 7 to 12 months.
University extension offices may also have a lab and be able to test for radon.
Radon levels can fluctuate over time, and are usually higher in the winter when your house and windows are sealed. This means you usually want to run a long-term test to verify, even if your numbers from the short-term test are high.
How To Fix Radon
I highly recommend hiring a professional to do this properly, and measuring again after they are done.
There are many actions that can be taken to reduce or remove radon:
Sub-Slab Depressurization. Dig a hole through the floor of the basement. Use pipes and fans to force radon out of the house. This reverses the air pressure difference between the house and soil, so radon is not drawn into the house.
This is usually the most effective fix, reducing levels around 90%.
Sealing your sump. If you have a sump pump to remove water, this may also leak radon into the house. Usually they can be sealed with an air-tight lid.
Sealing drains, floor gaps and cracks, and other locations.
Covering and sealing exposed soil or dirt, or adding an air barrier. e.g. in a dirt floor, root cellar, or crawlspace.
Adding ventilation, through an ERV/HRV. This helps but is less effective, with reductions between 25% to 50%.
The key is to do an air pressure test before you begin fixing to see whether your house and basement have a positive pressure, negative pressure, or how much. This will allow you to design the radon removal system to pump or fan out the correct amount of air so that the radon gas flows *out* of your house, rather than inside.
That means - if you want to do air sealing, you may in fact want to seal *before* installing a radon removal system. But if so - definitely fix your radon very soon afterward!
A radon professional should also be familiar with with the building code for your area, and know where the radon needs to be exhausted, how far away the pipes should travel, etc.
How Much Does It Cost?
Most estimates I find online are between $500 to $3,000 to fix radon. It may depend on your area and complexity of your basement.
For new houses and construction, the Energy Vanguard blog estimates that it costs 10% of the amount to avoid and mitigate radon when you are first building the house. It will cost 10x the amount to fix it after the house is built.
Conclusion: Get A Radon Test
Having recently completed a long-term radon test and discovered it needed fixing - I wish I had known about this years ago. Perhaps you can benefit from my mistake. Check your radon levels.