Kidde 20SAR Hardwired Smoke Alarm with AA Backup

1 / 7

Product guide

Kidde 20SAR Hardwired Smoke Alarm with AA Backup

The Kidde 20SAR is a hardwired smoke alarm with two AA backup batteries, photoelectric sensing, and an interconnect feature for compatible Kidde alarms. Its mains-powered design suits homes with compatible wiring, while battery backup is intended to provide operation during outages.

At a glance

Runs on hardwired AC power and includes two AA batteries for backup operation during outages, according to the listing.
The listing describes an 85-decibel alarm and red LED warning.
Can interconnect with compatible Kidde alarms. Models may have different connection options and requirements.
The manufacturer claims reduced false alarms from everyday cooking or steam. This is a stated feature, not a guarantee.

Price

$31.36Save 10%

Reference price: ~~$34.84~~

Price checked: Nov 13, 2026

View offer Ahead of Black FridayExplore the selection

Often bought together

Kidde Wiring Adapter for Hardwired Smoke & Combination Detectors, 20-9003 | Wiring Adapter for Hardwired Smoke and Combination Detectors, Easy Installation, No Rewiring, For Homes and Apartments

$5.97

Kidde Smoke & CO Detector, Hardwired & AA Battery Backup, 30CUAR, 1 Pack | Wired Interconnect Capability, Smoke and Carbon Monoxide Detection, LED status lights, Ideal for Homes and Apartments

$66.00

Pros and cons

Pros

Hardwired operation with AA backup avoids relying on batteries as the primary power source.
Interconnection with compatible alarms can make connected units sound together.
Compact listed dimensions of 1.88"D x 5"W x 5"H.

Technical specifications

11 specifications

Identity
Brand	Kidde
Model	20SAR
Alarm type	Smoke Detector
Sensor type	Photoelectric
Style	9th Edition

Power and battery
Power configuration	Corded Electric

Dimensions and construction
Dimensions listed	1.88"D x 5"W x 5"H
Color	White
Enclosure material	Plastic

Operating environment
Operating humidity	Up to 95% relative humidity (RH), non-condensing
Upper temperature rating	100 °F

What to know before buying

The included AA batteries provide backup rather than the primary power source. Customer feedback reports some backup batteries draining within months, alongside reports of easy installation and working interconnection. Confirm wiring and compatibility with your existing alarms before purchase.
The manufacturer describes a 10-year limited warranty on the alarm, not a battery performance warranty. It also advises replacing the alarm after 10 years or when end-of-life alerts begin.

Listing details to confirm

The listing identifies the style as 9th Edition but separately claims testing to UL 217 10th Edition. Its faster-detection claim also varies: a feature says over 25% faster, while the detailed explanation specifies 29% average in an internal comparison of smoldering wood fires against leading 8th Edition products. These claims and the claimed reduction in cooking or steam alarms are manufacturer statements, not independently verified measurements.

Who is it for?

A good fit for

Homeowners replacing a hardwired smoke alarm who want AA backup for power outages.
Installations that use compatible Kidde alarms and can benefit from interconnection.
Buyers seeking a smoke-only alarm rather than a smoke-and-carbon-monoxide combination unit.

Less suited to

Locations without compatible hardwired power or for buyers seeking a standalone battery-powered alarm.
Buyers who need carbon monoxide detection from the same unit.
Buyers expecting the backup batteries to be maintenance-free. The manufacturer recommends changing batteries every 6 months, and customer feedback includes reports of faster battery drain.

Kidde 20SAR Hardwired Smoke Alarm with AA Backup · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.2 / 5 · 767 ratings

5 stars71%71%
4 stars10%10%
3 stars3%3%
2 stars3%3%
1 star13%13%

Customer feedback highlights easy installation and positive reports about interconnection, but also mixed reliability and quality experiences. Some customers report backup batteries draining every 2–3 months, alarms chirping at night or signaling low battery, and units not lasting a year. These are customer-reported experiences rather than established outcomes. They matter especially for a hardwired model because its AA cells are backup power, so battery monitoring and checking the unit's alerts remain important. Aggregate ratings lean positive overall but include a notable low-star share, consistent with caution rather than a uniformly positive experience.

Positive themes

Customers describe installation as easy.
Customers report that interconnection works well.

Negative themes

Some customers report backup batteries draining within a few months.
Customers report nighttime chirping and low-battery beeping.
Some customers report units failing after false alarms or not lasting a year.

Mixed feedback

Customers give mixed feedback about reliability, build quality, and value.

Frequently asked questions

What powers the Kidde 20SAR?

It uses hardwired AC power and includes two AA batteries for backup operation during outages.

Can it connect to other smoke alarms?

The listing says it can interconnect with compatible Kidde alarms. Interconnection options and requirements vary by model, so check the user guide and compatibility before connecting units.

Does this alarm detect carbon monoxide?

No. The supplied product information describes smoke detection only.

How often should the backup batteries be changed?

The manufacturer advises changing the batteries every 6 months. Customer feedback also reports some batteries draining sooner, so monitor the unit and follow its user guide.

How long does the manufacturer say the alarm should be used?

The listing advises replacing it after 10 years or when end-of-life alerts begin. It also describes a 10-year limited warranty on the alarm, not battery performance.