First Alert Carbon Monoxide Detector
No Outlet Required, Battery Operated, CO400, White, 2 Count (Pack of 1)
Price as of 2026-06-05. Check Amazon for the current price.
Quick Decision
Price Intelligence
Currently $34.98 — the 90-day average is $33.90.
All-time low: $19.80 on Thu Oct 07 (from 182 price checks).
Is This Right For You?
- •Budget-conscious shoppers — priced below 79% of Carbon Monoxide Detectors
- •Risk-averse buyers — 22,922+ reviews give a highly reliable picture
- •First Alert loyalists — the brand spans 100 products in our database
- •First Alert Carbon Monoxide Detector offers a better rating (4.7/5) at a similar or lower price ($24)
- •Kidde Carbon Monoxide Detector — 31% cheaper at $24 (Score A)
- •Kidde Carbon Monoxide Detector — higher rated at 4.7/5 ($36)
📊 Based on data analysis of 53 products in this category.
Mubboo Score: A+
How It Compares
This Product First Alert Carbon Monoxide Detector | Most Popular Kidde Carbon Monoxide Detector | Best Rated First Alert Carbon Monoxide Detector | Best Value Kidde Carbon Monoxide Detector | |
|---|---|---|---|---|
| Price | $34.98 | $36 | $23.99 | $23.97 |
| Rating | 4.6/5 | 4.7/5 | 4.7/5 | 4.8/5 |
| Reviews | 22,922 | 35,752 | 22,830 | 1,338 |
| Mubboo Score | A+ | A+ | A+ | A |
Quick Specs
- Alarm
- Audible, Visual
- Color
- White
- Style
- Battery Powered
- Unit Count
- 2.0 Count
- Item Weight
- 0.8 Pounds
- Sensor Type
- Electrochemical
- Manufacturer
- First Alert
- Model Number
- CO400
What People Say
Synthesized from 40 reviews · 100% verified purchases.
Choose a model with a digital display if you want to see real-time CO levels. Note that the low-battery chirp can be mistaken for a smoke detector, so test early; also remember these need replacement after 10 years.
- Plug-and-Play Installation
- Peace of Mind & Reliable Protection
- Battery Backup for Outages
- Loud Alarm for Safety
- Portable for Travel
- No Digital Display on Basic Units
- Low-Battery Chirp Resembles Smoke Detector
Expert Picks in Carbon Monoxide Detectors
- Kidde Smart Smoke + Carbon Monoxide Alarm — Best smart smoke alarm
- First Alert SC5 Hardwire Smart Smoke and CO Alarm — Works with Nest Protect units
- Kidde Ring Smart Smoke + Carbon Monoxide Alarm — Ring alarm users
Category recommendations from independent expert publications. Source links in References.
Related Video Reviews
- 📹 What Most Homeowners Don’t Know About Carbon Monoxide Detectors — The DIY HVAC Guy
- 📹 Best Carbon Monoxide Detectors in 2026 — wiredtech
- 📹 7 Best Carbon Monoxide Detector 2026! Tested & Tried — Everything Under Control
Key Features
- ✦Keep your family safe with this 2-pack of easy to use, battery operated carbon monoxide alarms; Battery powered alarms provide continuous monitoring of CO levels, even if there's a…
- ✦Features an advanced electrochemical carbon monoxide sensor that accurately detects carbon monoxide levels, no matter where the detector is placed in the room
- ✦A loud 85-decibel alarm sounds when CO levels reach dangerous levels
- ✦To ensure complete protection make sure to place one on each level of your home and in each bedroom
- ✦5-year limited warranty; Equipped with end-of-life signal chirp, so you know when it’s time to replace the unit for safety
Source: product listing on Amazon.
About First Alert
- 100 products in our database
- Average rating: 4.6/5 across all products
- Price range: $13.98 – $648
- Categories: Carbon Monoxide Detectors, Fire Extinguishers, Smoke Detectors
Other Carbon Monoxide Detectors
Featured in Our Reviews
Bottom Line
First Alert Carbon Monoxide Detector earns Mubboo Score A+. Priced at $35, around its typical level. Rated 4.6/5 from 22,922+ reviews. Strong buy if: budget-conscious shoppers, risk-averse buyers. Skip if: first alert carbon monoxide detector offers a better rating (4.7/5) at a similar or lower price — Kidde Carbon Monoxide Detector (Score A+, $36) may fit better.
Frequently Asked Questions
Is the First Alert Carbon Monoxide Detector worth buying in 2026?
It earns a Mubboo Score of A+, with a 4.6/5 rating from 22,922 reviews — better than 60% of Carbon Monoxide Detectors we track.
How much does the First Alert Carbon Monoxide Detector cost?
It is currently $34.98. The 90-day average is $33.90 and the all-time low we recorded is $19.80.
How does the Carbon Monoxide Detector compare to other Carbon Monoxide Detectors?
The category's most-reviewed alternative is the Kidde Carbon Monoxide Detector (4.7/5, 35,752 reviews, $36). The Carbon Monoxide Detector carries a Mubboo Score of A+ vs A+.
Sources & References
Mubboo may earn a commission from purchases made through links on this page. Prices and availability are accurate as of the last sync (2026-06-05) and may change.