Which is better, First Alert CO615 or Google Nest Protect?

Based on our trust score analysis, First Alert CO615 scores 9.2/10 compared to Google Nest Protect at 9.0/10. First Alert CO615 ranks higher across expert reviews, user sentiment, and value metrics, making it the stronger choice overall.

What is the price difference between First Alert CO615 and Google Nest Protect?

First Alert CO615 is priced at $24.00 – $39.00 and Google Nest Protect is priced at $109.00 – $129.00. Google Nest Protect is the more expensive option at $109.00 – $129.00, while First Alert CO615 comes in at $24.00 – $39.00.

Is Google Nest Protect worth the extra money over First Alert CO615?

Google Nest Protect ($109.00 – $129.00) has a value score of 8.2/10 compared to First Alert CO615 ($24.00 – $39.00) at 9.2/10. First Alert CO615 offers better value for money despite the lower price point.

Home / Carbon Monoxide Detectors / First Alert CO615 vs Google Nest Protect

First Alert CO615 vs Google Nest Protect

Name: Google Nest Protect
Brand: Google
Rating: 4.6 (1 reviews)

Head-to-head comparison based on trust scores, features, pricing, and real user feedback.

Our pick: First Alert CO615 (Trust Score 9.2 vs 9.0)

First Alert CO615

First Alert

$24.00 – $39.00

9.2

Excellent

Runner-Up

Pros

+Flexible plug-in or tabletop placement
+UL 2034 certified
+Digital CO level readout

Cons

−Battery backup requires replacement
−Basic design without smart features

Don't buy if

⚠ Place the detector at knee height near sleeping areas, not in the kitchen or garage where combustion byproducts may cause false readings.

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Google Nest Protect

Google

$109.00 – $129.00

9.0

Excellent

Best Value

Pros

+Voice alerts name danger type and location
+Phone notifications and remote silence
+Automatic self-testing

Cons

−Most expensive CO detector
−Requires Google Home ecosystem

Don't buy if

⚠ The Nest Protect has a 10-year sealed battery lifespan; it cannot be battery-replaced and the entire unit must be discarded after 10 years.

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Score Comparison

Metric	First Alert CO615	Google Nest Protect
Trust Score	9.2 ✓	9.0
Expert Score	9.1 ✓	8.8
User Sentiment	9.2 ✓	9.1
Value Score	9.2 ✓	8.2
Complaint Risk	8.6 ✓	8.7
Price	$24.00 – $39.00	$109.00 – $129.00

The Verdict

First Alert CO615 wins this comparison with a Trust Score of 9.2 vs 9.0. It's rated "Runner-Up" and scores higher across the majority of our evaluation criteria. However, the Google Nest Protect may be a better fit depending on your specific priorities — check the pros and cons above.

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