Skip to main content
First Alert CO400 Carbon Monoxide (CO) Detector, Battery Operated Alarm, 1-Pack - Amazon product rated Grade B

First Alert CO400 Carbon Monoxide (CO) Detector, Battery Operated Alarm, 1-Pack

4.6(22,382 reviews)

AI-powered analysis of this product's reviews to help you make an informed purchase decision.

Last analyzed: February 13, 2026

Trust Score Gauge showing B grade with 88% scoreCircular progress indicator displaying trust score from 0 to 100 percent, currently at 88 percent
B
0%🟢
Very Good

Trust Score

How trustworthy are the reviews for this product?

✓ Reviews appear trustworthy
Analysis is 62.6 days old. Re-run to get the latest review data and insights.

What Our Analysis Found

Detailed review analysis for First Alert CO400 Carbon Monoxide (CO) Detector, B...

Lean positiveGenerally reliable feedback

The First Alert CO400 Carbon Monoxide Detector appears to be a reliable product based on the analyzed data. An overall trust score of 88 out of 100 and a solid B grade suggests a generally positive reception. The high rating of 4.6/5, derived from a subset of over 22,000 total reviews, reinforces this positive assessment. The strengths of this product lie in the authenticity and consistency of its reviews, the trustworthiness of the reviewers, and the natural distribution of ratings, all scoring above 90. This indicates that customer feedback is genuine, reliable, and aligns well with the product's performance. Several key patterns emerge from the factor scores. The high scores in Review Velocity, Reviewer Credibility, and Product Consistency suggest that the product has maintained a steady stream of positive feedback from credible sources over time, indicating consistent performance and reliability. However, the slightly lower score in Seller Reputation (78/100) is worth noting. While not alarmingly low, it suggests that some customers may have reservations about the seller, potentially related to shipping, customer service, or other aspects of the purchasing experience. For potential buyers, the First Alert CO400 seems like a dependable choice for carbon monoxide detection. The strong scores in review quality, reviewer credibility, and product consistency inspire confidence in its effectiveness and reliability. However, it would be prudent to research the seller and read recent reviews specifically addressing the seller's performance to ensure a smooth purchasing experience. Considering the importance of a CO detector, prioritizing a reputable seller, alongside the product's inherent qualities, is a wise approach.

Key Signals Detected

Reviewers frequently mention: "peace of mind", "easy to install"
Some generic promotional language detected: "works great"
Review content shows strong language diversity (81/100)
Review posting patterns appear natural and organic

Sample Review Excerpts

Works great, looks good. Definitely recommend. Great deal for the price.

These are direct excerpts from analyzed reviews.

What We Couldn't Verify

Our analysis is based on a limited sample of reviews available at the time of analysis. Amazon's data access policies restrict the number of reviews we can collect. Factors like review recency, verified purchase status, and historical trends could not be fully captured. We recommend reading individual reviews on Amazon for additional context.

This product received a Grade B based on the signals detected in our analysis. We recommend reading individual reviews on Amazon for additional context.

Our Recommendation

✅ Recommended

Analysis Date

February 13, 2026

Reviews Analyzed

22,382

What This Score Means for First Alert CO400 Carbon Monoxide (CO) Detector, Battery Ope...

After analyzing 22,382 reviews, First Alert CO400 Carbon Monoxide (CO) Detector, Battery Ope... received a trust score of 88/100 (Grade B). This is a strong result that places it among the more trustworthy products we've analyzed in this range.

The strongest signal was Review Velocity (95/100), while Seller Reputation (78/100) was the area that needs the most attention.

Key Analysis Factors:

  • Review Velocity scored 95/100, indicating strong authenticity signals
  • Reviewer Credibility scored 95/100, indicating strong authenticity signals
  • Product Consistency scored 95/100, indicating strong authenticity signals

What Reviewers Are Saying

Based on our analysis of customer reviews for First Alert CO400 Carbon Monoxide (CO) Detector, B..., here are the most common themes and opinions shared by verified buyers:

✓ Commonly Praised:

peace of mindeasy to install

Overall sentiment: The First Alert CO400 carbon monoxide detector scores well overall with high ratings for reviewer credibility, product consistency, and review activity. While the content of the reviews is good, and the seller's reputation is acceptable, these areas could be improved. Overall, this product seems like a good choice based on customer reviews.

Frequently Asked Questions

Are the reviews for First Alert CO400 Carbon Monoxide (CO) D... real?

Our AI analyzed 22,382 reviews and assigned a 88% trust score (Grade B). The strongest authenticity indicator was Review Velocity at 95/100.

What did the analysis find for First Alert CO400 Carbon Monoxide (CO) D...?

The First Alert CO400 carbon monoxide detector scores well overall with high ratings for reviewer credibility, product consistency, and review activity. While the content of the reviews is good, and the seller's reputation is acceptable, these areas could be improved. Overall, this product seems like a good choice based on customer reviews.

Should I buy First Alert CO400 Carbon Monoxide (CO) D...?

Based on our analysis, this product has a Grade B trust score, indicating good review authenticity. The data suggests most reviews reflect genuine customer experiences.

Shopping Advice Based on Our Analysis

Based on our analysis of 22,382 reviews , here's our Grade B assessment:

  • 💡This product's product consistency scored 95/100, which is a positive indicator of review authenticity
  • 💡Reviews appear highly authentic — you can generally trust the consensus opinions for purchase decisions
  • 💡With 22,382 reviews analyzed, our confidence in this assessment is high

Ready to make your purchase?

Based on our analysis, you can make an informed decision. Click below to purchase this product on Amazon.

High Quality Product

As an Amazon Associate I earn from qualifying purchases

Grade BFirst Alert CO400 Carbon Monoxide (CO) Detector, Battery Operated Alarm, 1-Pack