How RadonIndex ranks companies

How does RadonIndex rank companies?

Three pillars, added together. The score is deterministic, meaning the same data always gives the same order, and it is applied identically to all 35 listings.

Why is what a company says about itself worth the most?

Because radon is the one trade where a claim can be checked by the person reading it. The Canadian National Radon Proficiency Program certifies individuals to measure or mitigate radon, and it publishes a lookup where you can put in a certificate number and see for yourself. No star rating tells you that. So a company stating C-NRPP certification on its own site earns 18 of the 40 in this pillar, and every profile prints the sentence we found it in and links the C-NRPP check beside it.

Read the labels literally. Every one begins “Says it is”, because that is all that happened: a crawler read a sentence on a company's website on August 31, 2026. We did not phone C-NRPP, ask for a certificate number, or look at an insurance policy. A sentence that reads as advice to you rather than a claim about the company is thrown away before it is scored, so a page telling readers to “use a licensed professional” earns nothing.

Of 35 listings, 35 were fetched and read. Where a row is worth nothing to a company, its profile shows that row at zero rather than hiding it: a website that does not mention certification is a fact worth seeing.

How do reviews count?

35 points, split between the rating (23) and how many reviews stand behind it (12). A raw star rating is misleading when the review count is tiny, so each rating is blended toward the dataset average as though every company began with 10 imaginary reviews at the mean of 4.90 stars. A 5.0 built on four reviews is pulled toward the middle until it earns more history; a 4.8 over three hundred barely moves. The depth half is logarithmic and reaches full value at 120 reviews, because the step from five reviews to twenty-five teaches a reader far more than the step from a hundred and fifty to three hundred.

Reviews are worth less here than on most directories in this family, and the reason is specific to radon. Two thirds of these companies do radon inside a home-inspection, air-quality or restoration practice, so their review counts were earned largely on other work. A home inspector with two hundred reviews is not thereby a better radon mitigator, and ranking as though they were would be ranking on the wrong evidence.

What counts as record and reach?

25 points for whether the record is complete enough to act on, and whether the company's own website answered when we fetched it on August 31, 2026. These are observations about the record, never judgements about the business.

What we take a failed fetch to mean

This is worth spelling out, because getting it wrong publishes a false statement about a real business. A refusal is not a death. A bot block, a timeout, or a robots.txt that tells us to go away are all things a working website does, and a person with a browser is very likely served the page normally. What we withhold credit for is a domain that does not answer at all, or one that answers perfectly well with somebody else's business, because a lapsed domain gets rebought.

No listing is ever removed, hidden or pushed out of sight for any of this. A company with a lapsed domain is a company with a lapsed domain, and it keeps its page. When we fetched all 35 sites on August 31, 2026, every one of them answered.

What does this look like in practice?

Not with invented companies, which nobody can check. These are the top, the middle and the bottom of the live list, with each pillar shown separately. Open any profile and the same breakdown is printed there, row by row.

The spread across all 35 listings runs 12 to 72 with a median of 51. A low score is a thin record, not a verdict on a business: a company that has done excellent radon work for twenty years and never mentioned C-NRPP on its website will score below one that says so on its home page. That is a limit of reading websites, and it is why the number is a shortlist tool and not a recommendation.

Which companies does RadonIndex exclude or rank low?

RadonIndex does not know which of these businesses have closed, and this page used to say it dropped them. The records behind this site were collected in August 2026 and the export carries no closed-or-open field, so nothing has ever been dropped for being closed. Check the company's own Google record before you rely on it. Nothing is excluded for scoring low. A company with few reviews and a website that mentions no certification scores low and still gets a full profile page, in the list, with every row of its score shown including the empty ones. The only companies kept out of the top-rated and best-of modules are those the score itself places outside them, which is the same rule applied to everyone.

Every web address on this site was fetched on August 26, 2026. 1 of them is not linked from their profile: the domain no longer answers, or it answers with a business that has nothing to do with the listing, because a lapsed domain gets rebought. A bot block, a slow response or a “coming soon” page is not counted, because none of those is evidence a site is gone. The company stays listed either way: a lapsed domain is not evidence anyone stopped trading.

Where does RadonIndex's data come from?

Ratings, review counts and business details come from public Google Maps profiles. Each record is then enriched from the company's own website, and that website is what decides whether the company is listed at all: it has to name a radon service. Prices across 2 categories come from published Canadian sources that we fetch and cache, and a script re-finds every figure inside its cached page before the site is allowed to build. We do not scrape private data or buy reviews.

How often does RadonIndex refresh its data?

The current RadonIndex dataset is stamped August 2026. We refresh review data and re-run the ranking on a rolling basis so positions track the current data, and every page shows a visible last-updated date. If a business is sold, closed or corrects its details, email us and we update the record between scheduled refreshes.

Who is missing from RadonIndex?

The sweep returned 138 candidate businesses and 35 are listed. Of the 103 dropped, only 7 were dropped because we read their website and it names no radon service. 61 were dropped because there was nothing to read: no website published, or a site that would not load for us. That is a limitation of our method, not a finding about those businesses, and it is the honest reason this directory is smaller than the trade.

These 5 are the ones that bother us most. Each trades under a name containing the word radon and appears in this region, and each is absent from the list above only because we could not read a website for it. If one of them is you, email hello@radonindex.ca and we will add you.

• Toronto Radon Removal - 2967 Dundas St W #389D, Toronto, ON M6P 1Z2 - no website published
• Radon Ontario Services - website did not load
• Radon Guardian - website did not load
• Pro Radon Testing - no website published
• RadonCERT - 150 King St W Ste 200, Toronto, ON M5H 3B7 - no website published

What are the limits of RadonIndex's rankings?

More than usual, and it matters more here than on most directories. A Google rating measures how people felt about dealing with a company. It cannot measure whether a radon system actually lowered the level in a house, because almost no customer can tell. So treat the ranking as a way to build a shortlist and nothing more. We do not verify WSIB coverage, insurance or licences. We record a C-NRPP certification claim only when we found it in the company's own website text, and we show you that sentence: certification is held by a person rather than a company, so check the certificate number with C-NRPP directly. Get two written quotes, and insist on a test after the work rather than trusting anyone's word, ours included.