I'm pulling frequent measurements of household radon levels
into Home Assistant, using an integration with my Airthings
radon sensor. The levels are much lower than they used to be,
a day after we turned on a new radon mitigation system. This
is the "yay we did it" point of a project that has been nagging
at me for a long time.
If you live in a house in an area with elevated radon levels, I
would encourage you to skip the multiple years it took me to get
everything sorted out. Here's what I would tell my earlier self.
There's two ways to test for radon. One is a one-time kit, that you
set into a room and then send back to a lab for results. They are
cheap (or maybe free from your health department), but they give
a one-time reading. The other is with a sub-$200 electronic sensor
that does a continuous readout, measuring every few minutes and
reporting to your smart phone and a cloud server. I totally and
completely recommend spending less than $200 to get something
in place to monitor over time and to help you be sure that any
mitigation you put into place actually works.
The Ann Arbor District Library has radon measurement tools for
checkout. You can also buy them for continuous monitoring. Mine
is from Airthings.
https://aadl.org/catalog/record/10625120
When you run the sensor for a while, you will discover that levels
vary depending on the time of day, atmospheric pressure, the
phase of the moon (?), and other things that seem to be random.
You will also note that if you have a room that doesn't get much
ventilation that the levels will build up. We have a whole-house
fan connected to our thermostat, and running more frequently kept
the levels down some. Cracking open a window to let in fresh air
will also help. We saw a variation around a mean with a 50% +/-
swing either way, and one alarming day that it spiked up to 5x
typical readings.
If your radon levels are within a good range (under 50 Bq/m^3 or 1.3
picocuries per liter) you're in good shape. If they are in a bad way
you'll want to contact a professional for radon mitigation. (I am
not that professional, just a homeowner.)
We got a service to come out and do the work. Day one was about two
hours of a two-person job, one inside drilling a hole in the foundation
to insert a vent pipe that evacuates gases from under the basement,
the other an outside job anchoring that vent pipe and an inline fan
to the side of the house where the exhaust gases go above the roofline.
Day two was an electrician wiring up the fan and installing an outdoor
switch to turn it off in case of maintenance. Your process might be
different if you have a different house than ours - in particular
there's other things you need to do if you have a crawl space.
Flip the switch, turn everything on, start to monitor the Airthings
display on my phone. The levels immediately start to go down and keep
going down for at least 24 hours. The new readout (30 Bq/m^3) is in the
good range, and the lowest I've seen it since I started watching.
I'm also running Home Assistant which has a very nice set of tools
for collecting a time series of data and graphing it. The Home Assistant
integration was easy to do (you set up an API key, you plug in the
values into HA, and you're good to go).
https://www.home-assistant.io/integrations/airthings/
I'm not generally a big fan of "home automation" as it's practiced,
but sure enough sometimes it can be very handy. It would be possible,
for instance, for me to have Home Assistant do something really annoying like sound
an air horn powered by a smart switch every time the readings went
above a threshold.
My rule for home automation is "don't build a haunted house". It's
also "keep your family safe from danger". I'm glad I did this project!
But I really wish I had someone walk me through it and spell out some
options and explain to me just how relieved I would feel now that the
Bad Air number has gone way down.
Vendors, for reference; specific contractors for radon work depends on your
local area.
Airthings: https://www.airthings.com
Airthings Wave Radon. https://amzn.to/3R3Hpmg This is an Amazon Affiliates link.
I would get some small cut of the purchase price if you buy this. I didn't
buy mine from Amazon - instead got it direct from Airthings. Your choice.
Protect Environmental Ann Arbor.
https://www.protectenvironmental.com/locations/michigan-mi/ann-arbor-radon-and-vapor-intrusion-services/
These folks did our house. It's the organization formerly known as Protech,
apparently some transition to a new name. If you are not in Ann Arbor this
company also does business in other locations. My experience was good so
far.
Michigan Indoor Radon Program
https://www.michigan.gov/egle/about/organization/materials-management/indoor-radon
From the State of Michigan EGLE, with a map of test results showing
typical levels throughout the state that you can zoom into by zip code.
Ann Arbor 48104 averages a reading of 4 with a median of 3, within the
"Mitigation Recommended" zone.
"Radon", US EPA
https://www.epa.gov/radon
National program with maps of areas with high radon concentrations,
and links to state and tribal programs for mitigation.
