Buying a radon monitor? How to make sure you purchase one that actually works

Anyone hoping to check their home’s radon level can now pick from dozens of different radon monitors sold online or in stores — but experts warn many of those devices don’t actually work.

Plenty of Canadians install faulty monitors, only to find out later that they aren’t approved or certified, cautioned Pam Warkentin, the executive director of the Canadian Association of Radon Scientists and Technologists (CARST), which runs the country’s certification program alongside Health Canada.

“I have to tell them that they can’t really base any decisions on those detectors and need to go purchase another one.”

Wasted money and time add up fast. Electronic monitors can be hundreds of dollars each, and people are encouraged to test for a minimum of three months. Warkentin recalled speaking to one homeowner who purchased devices for himself and his adult children, but only learned they had been recalled until after he’d used his own monitor for several months.

Those kinds of “scam” devices pose a public health risk since they don’t show a building’s actual radon level, Warkentin added. 

She said misleading readings can discourage homeowners from taking steps to reduce household radon, an invisible, radioactive gas that can cause lung cancer through long-term exposure. Millions of Canadian homes likely have high levels, research shows, while radon-induced lung cancer is thought to kill an estimated 3,200 people each year.

“Many people are going to be testing and have a low level and not even question the device,” Warkentin warned.

So how do you properly test your home for radon? And what monitors should you avoid?

WATCH | The cancer-causing gas hiding in millions of homes:

The cancer-causing gas hiding in millions of homes

Radon gas is invisible, toxic and millions of Canadians have no idea it’s hiding in their homes. For The National, CBC’s Lauren Pelley breaks down the health risks and what you can do to keep your home safe.

How to test for radon

Health Canada recommends testing your home for three months or more, and ideally during the winter months when homes are sealed up and radon readings can be highest.

“There’s no way to predict it,” said Warkentin, who is also a project manager for Canada’s Take Action On Radon awareness program. “Everybody just needs to test.”

WATCH | How to check for radon in your home:

How to check for radon gas in your home

With millions of Canadians living in homes with high amounts of invisible and toxic radon gas, CBC’s Lauren Pelley explains how to test for it, and what to do if it’s found.

To do that long-term testing, you can either hire a radon measurement professional or get your own test kit.

Some communities provide free radon monitors through libraries or local public health units, but typically, homeowners end up paying out of pocket for their own devices. And there are a wide variety of options out there, ranging from passive tracking devices to electronic monitors that display real-time results on screens and apps.

The issue, Warkentin said, with some devices is they simply don’t work, instead providing “false low” readings.

“I don’t know what they’re reading, but they’re not reading the radon level,” she said. “So they’re giving you a number, but it’s not based on … what the radon level in the home [actually] is.”

Find an approved monitor

At Health Canada’s radon lab in Ottawa, a team of scientists conducts tests on home radon monitors to see how well they perform within regular household conditions.

“We tested almost 40 different devices that are available,” Pawel Mekarski, the federal department’s head of radon technical operations, told CBC News when our team visited the lab in January. “We’ve seen the market kind of explode in the last five years.”

Radon monitors are formally approved and certified through the Canadian radon certification program operated by CARST, with Health Canada’s oversight. 

As of March 2026, only six electronic monitors have been approved for use:

• Airthings Corentium Home.
• Airthings View.
• Aranet RN+.
• Ecosense EcoQube.
• Ecosense RadonEye.
• SunRadon Luft.

Canadians looking for one of those certified devices can find a list of provincial suppliers through the Take Action on Radon program.

WATCH | Family urges other Canadians to test after finding high radon levels:

Family, shocked by high levels of radon in their home, now wants other Islanders to test

A family in Stratford, P.E.I., tested for radon in their house, and the results showed high levels of the invisible, toxic gas. They’re now taking steps to mitigate the issue, and pushing for others to check their homes. CBC’s Stacey Janzer has more.

Check for recalls

If you decide to buy a radon monitor through online storefronts or local hardware stores instead, Warkentin said it’s buyer beware.

“We went from [a few] devices in our first consumer report that we had on recall, to now evaluating over 20 devices that we’re suspicious of,” she said.

Canada’s radon certification program currently provides a list of more than a dozen devices that are either not yet approved or have already been recalled by Health Canada.

While Warkentin recommends homeowners check that list before purchasing a radon test kit, she said it’s hard to keep up with the changing landscape since manufacturers are regularly releasing new devices — or rebranding faulty ones.

“It seems like what’s happening is they either get bad reviews on these online retailers, or they get recalled by Health Canada, or they’re on our non-approved list,” she said. “Then [manufacturers] pull them, rebox them, give them a new name and then they start selling them again.”