#1
Rapid Radon Relief
“Rapid Radon Relief did an amazing job for us! 10 out of 10 on customer service, professionalism and attention to detail. I will recommend them to anyone looking for radon mitigation.” — Google review
Experts Reviews · 2026 Ratings
The Best Radon Testing Services in Northglenn, CO
We graded 6 companies on seven things customers actually report: satisfaction, reliability, workmanship, value, momentum, track record and how owners handle complaints.
$146typical jobMedian of the bill customers reported in their Google review (Google asks reviewers for a price range; we use the middle of each range).
99%say the price was fairOf customers who rated the price, the share who chose “Great price” or “Reasonable” rather than “Overpriced”.
4.93★average ratingPlain average of every Google star rating we collected for these companies.
1.7%bad jobs (1–2★, 2 yrs)Share of 1–2★ reviews in the last 24 months — or the 20 newest reviews when the company had fewer than 20 in that time.
From 25,240 Google reviews of 71 top-rated radon testing services nationwide; 6 of them in Northglenn, CO. Updated November 3, 2026.
Find the right company for your job
Pick the job — we re-rank companies by how customers rated that exact job.
Overall ratings
Experts Score 0–100Experts Score (0–100)Absolute quality first: recency-weighted star average (≈54%), share of 1–2★ reviews (≈24%), customers’ price verdicts (≈14%), owner replies to critical reviews (≈7%); minus up to 10 points each for complaints flagged in Google review highlights and for a real slide in recent ratings. Hover a company’s score on its page for the full breakdown. and a letter grade per factor (A = top 20% of radon testing services).
| # | Company | ScoreExperts Score (0–100)Absolute quality first: recency-weighted star average (≈54%), share of 1–2★ reviews (≈24%), customers’ price verdicts (≈14%), owner replies to critical reviews (≈7%); minus up to 10 points each for complaints flagged in Google review highlights and for a real slide in recent ratings. Hover a company’s score on its page for the full breakdown. | FactorsFactor grades, in orderSatisfaction (54%): Recency-weighted star average (2-year half-life), shrunk toward the category mean by review volume; the company’s own lifetime average as the prior; absolute: 4.0★ = 0, 5★ = 100.Reliability (24%): How rarely jobs go badly: share of 1–2★ reviews — 60% the last 24 months (or the 20 newest if fewer), 40% all-time; 0% = 100, 15%+ = 0; the category percentile can only raise it.Craft & service (0%): Google review highlights: Quality, Professionalism, Responsiveness, Punctuality — how rarely reviewers flag them as a negative, per review since highlights began; 0% = 100, 5%+ = 0. Subtracted from the score (up to −10), never averaged in — clean highlights are the norm, not a bonus.Value (14%): Customers’ own price verdicts (Great / Reasonable vs Overpriced) and Value highlights; 65% absolute (all “reasonable” ≈ 80, “great” = 100), the category percentile can only raise it.Momentum (0%): Penalises only a real slide: last-12-month average below lifetime (−0.5★ = 0). Still 4.8★+ over the last year, or steady/improving = 100. Subtracted from the score (up to −10), never averaged in.Replies to reviews (7%): How often the owner publicly replies to reviews under 5★ (1–4★). Needs 3+ such reviews, otherwise not counted; 65% absolute (80%+ replied = 100), the category percentile can only raise it.One letter per factor score: A = 80+, B = 60–79, C = 40–59, D = 20–39, F = below 20. | ★Google star rating as shown on Google Maps. | Typical billMedian bill customers of this company reported in their reviews (needs 3+ priced reviews). |
|---|---|---|---|---|---|
| 1 | Rapid Radon ReliefNorthglenn, CO | A 100How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 59%100+58.7Reliability 26%100+26.1Value 15%100+15.2Experts Score= 100Not enough data for replies to reviews; its weight is shared by the others.Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAA– | 5.00 | — |
| 2 |  Rocky Mountain Radon MitigationNorthglenn, CO | A 99How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 59%99+58.1Reliability 26%100+26.1Value 15%100+15.2Experts Score= 99Not enough data for replies to reviews; its weight is shared by the others.Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAA– | 4.99 | — |
| 3 |  Protect Environmental Radon MitigationNorthglenn, CO | A 90How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%89+48.5Reliability 24%86+20.8Value 14%100+14.1Replies to reviews 7%90+6.4Experts Score= 90Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAA | 4.81 | — |
| 4 |  Affordable Radon ServicesNorthglenn, CO | A 87How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%90+49.1Reliability 24%83+20.1Value 14%100+14.1Replies to reviews 7%54+3.8Craft & service penalty94−0.6Experts Score= 87Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AAAAAC | 4.90 | — |
| 5 |  SWAT Radon MitigationNorthglenn, CO | A 82How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 55%80+43.6Reliability 24%70+17Value 14%99+14Replies to reviews 7%100+7.1Experts Score= 82Grade A: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | AB–AAA | 4.79 | — |
| 6 | American Radon MitigationNorthglenn, CO | B 77How the Experts Score is calculatedEach factor is scored 0–100 on absolute terms (standing in the category can only raise it), then weighted; problems flagged in review highlights or a recent slide in ratings are subtracted:Satisfaction 59%82+48.1Reliability 26%66+17.2Value 15%100+15.2Craft & service penalty99−0.1Momentum penalty70−3Experts Score= 77Not enough data for replies to reviews; its weight is shared by the others.Grade B: A = 80+, B = 60–79, C = 40–59, D = 20–39. Needs 10+ reviews. | ABAAB– | 4.92 | — |
What jobs cost
What customers paid, from the price Google asks reviewers to report.
| Job | Low25th percentile: 1 in 4 customers paid less than this. | TypicalMedian of the bill customers reported in their Google review (Google asks reviewers for a price range; we use the middle of each range). | High75th percentile: 1 in 4 customers paid more than this. | FairOf customers who rated the price, the share who chose “Great price” or “Reasonable” rather than “Overpriced”. |
|---|
Radon Testing Services in Northglenn, CO at a glance
How the 6 radon testing services we rated in Northglenn, CO compare, and what customers praise most.
Experts Score grades
A = score 80+, F = below 20.
- Grade A583%
- Grade B117%
- Grade C00%
- Grade D00%
- Grade F00%
Google ratings
Average stars per company.
- 4.90★ and up467%
- 4.80–4.89★117%
- 4.60–4.79★117%
- Below 4.60★00%
What customers praise
Share of Google review highlights.
- Quality6,69824%
- Professionalism7,31826%
- Responsiveness6,11322%
- Punctuality2,82810%
- Value5,19118%
Was the price fair?
All price verdicts left with reviews.
- Great price68240%
- Reasonable97057%
- Overpriced181%
- Not sure342%
Price verdicts by year
Share calling it great / reasonable / overpriced.
2025
2026
How we grade
Satisfaction (54%) — Recency-weighted star average (2-year half-life), shrunk toward the category mean by review volume; the company’s own lifetime average as the prior; absolute: 4.0★ = 0, 5★ = 100.
Reliability (24%) — How rarely jobs go badly: share of 1–2★ reviews — 60% the last 24 months (or the 20 newest if fewer), 40% all-time; 0% = 100, 15%+ = 0; the category percentile can only raise it.
Craft & service (penalty, up to −10) — Google review highlights: Quality, Professionalism, Responsiveness, Punctuality — how rarely reviewers flag them as a negative, per review since highlights began; 0% = 100, 5%+ = 0. Subtracted from the score (up to −10), never averaged in — clean highlights are the norm, not a bonus.
Value (14%) — Customers’ own price verdicts (Great / Reasonable vs Overpriced) and Value highlights; 65% absolute (all “reasonable” ≈ 80, “great” = 100), the category percentile can only raise it.
Momentum (penalty, up to −10) — Penalises only a real slide: last-12-month average below lifetime (−0.5★ = 0). Still 4.8★+ over the last year, or steady/improving = 100. Subtracted from the score (up to −10), never averaged in.
Replies to reviews (7%) — How often the owner publicly replies to reviews under 5★ (1–4★). Needs 3+ such reviews, otherwise not counted; 65% absolute (80%+ replied = 100), the category percentile can only raise it.
The 10 best-rated radon testing services in Northglenn, CO average 4.9★ on Google across 3,599 reviews. Rapid Radon Relief has the top rating (5.0★), and Affordable Radon Services has the most reviews (705). Updated November 2, 2026.
10 companies that meet our bar: rated 4.5★ or higher on Google, with a meaningful review history (3,599 reviews combined) and currently operating. Request a call back and the company will phone you directly.
#2
Rocky Mountain Radon Mitigation
“Excellent job, no issues, system seems to be working as expected, very clean and fast job, no complaints, very satisfied with the job so far. Thanks” — Google review
#3
Colorado Radon Mitigation
“Kelon did some good work and seemed to go pretty above and beyond. Plus a lot of home maintenance companies appear to have been taken over by hedge funds and turned their techs into sales people. I didn't catch that…” — Google review
#4
Radon Safety LLC
“They did a great job - quick, respectful, professional, and reasonable! Highly recommend. We had a new radon mitigation system installed on an existing home.” — Google review
#5
Affordable Radon Services
“Communication was amazing and the quality of work was the best you can ask for! Excellent pricing, Customer Service and the technician who actually did the work was super friendly and once again just had really good…” — Google review
#6
5280 Radon Mitigation
“Byron and Bryan were professional, knowledgeable and efficient. Great work, and pleasant to deal with. I highly recommend them!” — Google review
#7
RDS Environmental
“I'm happy with the work they did and would recommend. Very friendly folks and didn't mind all my questions when they were installing.” — Google review
#8
SWAT Radon Mitigation
“As a Realtor I use SWAT for radon mitigation in all my properties. Today I had them come out for my personal residence. Chris was fantastic. Super helpful. He was quick and thorough. We could not be happier with…” — Google review
#9
American Radon Mitigation
“Highly recommend, Jesse came to my house promptly, found the problem with my system and fixed it right away. He's very knowledgeable and helpful. I will use him anytime I need help with Radon in the future.” — Google review
#10
Protect Environmental Radon Mitigation
“Protect Environmental has been great to work with. They installed my system a year ago. I just had an issue with manometer, but they got someone out here quickly to take a look. Dean was very friendly, replaced…” — Google review
How we pick radon testing services in Northglenn
We scan Google Maps for radon testing service listings in and around Northglenn, keep only open businesses whose main category matches the service, and require a Google rating of at least 4.5 from at least 20 reviews. Companies are ordered by a confidence-weighted score that balances rating and review volume. We do not accept payment for placement.
Frequently asked questions
Who is the highest-rated radon testing service in Northglenn?
Rapid Radon Relief has the highest Google rating on our Northglenn list: 5.0 out of 5 from 363 reviews (as of November 2, 2026).
Which radon testing service in Northglenn has the most reviews?
Affordable Radon Services has the most Google reviews among the companies listed here: 705, with a 4.9★ average.
How are these radon testing services chosen?
Only open Northglenn-area businesses whose Google category matches the service, rated at least 4.5★ from at least 20 Google reviews. They are ordered by a confidence-weighted score of rating and review volume. Placement is never paid.