What a silent alarm does and does not prove · review
The older Kidde plug-in with a digital display, a 9V backup and 28,356 ratings at 4.7 out of 5.
Kidde gives 120V power, a 9V backup, a digital display and an 85 dB alarm.
A home CO alarm is built to hold off at low levels: see our UL 2034 page for the alarm windows. A silent alarm does not prove the air is free of CO.
If the alarm sounds, get everyone outside to fresh air and call 911 or the fire department from there. Check the replace-by date, and follow the manual and your local code on where to mount it.
Prices quoted in this text are dated readings and can differ from the live price at the top of the page.
| Power | Plug-in, 9V backup |
|---|---|
| Display | Digital LED, CO level |
| Alarm | 85 dB |
| Model | KN-COPP-3 |
| Sensor | Ionization in the table, which looks like an error |
| Amazon reference | B00002N86A |
The COPD is newer and names UL 2034 5th Edition.
The table says ionization, which is a smoke alarm term. Confirm with the manual.
8.5/ 10
Good, and overpriced against Kidde’s own newer COPD.
This model is listed on Amazon.com, at ≈ $70 at the last reading. Listed is not the same as in stock: availability changes daily, and the buy box shows the live price.
Details checked on November 14, 2026.
A buyer who trusts a long record over a newer model.
Specifications: the manufacturer sheet for wood heating equipment and the matching Amazon product page. Prices, ratings and availability: read on Amazon.com from a New York address. Every figure on this page names its source.
Same shelf, closest price — what the same spend else heats.
2 AA batteries · electrochemical · 85 dB · LEDs · Event Memory · portable
A small AA alarm with Event Memory, which records the last time it detected CO, with 2,356 ratings at 4.7 out of 5.
Best for: A cabin or travel alarm, or a second alarm at home.
≈ $25
plug-in · 2 AA backup · backlit display · 85 dB · UL 2034 5th Edition stated · rotating plug
A plug-in alarm with a CO display, a rotating plug and AA backup, naming UL 2034 5th Edition.
Best for: A bedroom or a stove room with a convenient outlet.
≈ $44
9V battery · electrochemical sensor · 7.2 oz · 10 to 95% RH
The default CO alarm: a simple 9V battery model with 22,134 ratings at 4.6 out of 5, with almost nothing written on the listing.
Best for: A second alarm near a stove or in a bedroom, on a budget.
≈ $22
