# SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery

SITERWELL GS509A is a battery-powered photoelectric smoke detector with a replaceable 9V battery, test/mute button, and low-battery warning. The listing calls out a 10-year product life, but describes that period as dependent on continuous battery replacement, not a 10-year battery.

- [Original product page](https://best-deals.pro/product/siterwell-gs509a-photoelectric-smoke-detector)
- [View offer](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)
- Market: US
- Language: en-US
- Currency: USD
- Brand: SITERWELL
- Model: GS509A
- Category: Electronics > Smart Home & Security > Alarms & Sensors
- Price: 113.53 USD
- Previous price: 132.77 USD
- Discount: 14%
- Price checked: 2026-11-13T05:46:34.994Z
- Rating: 4.4 / 5
- Reviews: 762

Prices and deal status are the latest recorded data, not a guarantee of availability. Confirm the price and availability with the store.

## At a glance

- Photoelectric sensing is presented as suited to detecting slow-smoldering fires that produce light smoke.
- The listing describes a test/mute button and says weekly testing is required.
- A low-battery warning is claimed. The listed battery is a 9V type.
- The product life claim depends on continuous battery replacement. The listing does not describe this as a 10-year battery.

## Pros

- Replaceable-battery design avoids relying on a sealed battery for the detector's claimed product life.
- The test/mute button and low-battery warning provide stated functions for routine checking and battery maintenance.
- A mounting bracket and magnetic fastening kit are listed in the package contents.

## Cons

- The claimed 10-year product life requires continuous battery replacement, so it does not mean one battery lasts ten years.

## Specifications

### Identity
- Brand: SITERWELL
- Model: GS509A
### Power and sensing
- Power configuration: Battery Powered
- Sensor type: Photoelectric
- Alarm: Audible
### Dimensions and installation
- Dimensions listed: 3.93"D x 3.93"W x 1.39"H
### Materials and operating conditions
- Material listed: ABS
- Operating humidity: 10-95% RH non-condensing
- Upper temperature rating: 37.8 °C
### Appearance
- Color: White
- Product style: Replaceable Battery \(NEW\)

## Before you buy

- The listing says the detector has a one-year 9V battery and a ten-year product life with continuous battery replacement. Treat these as separate claims, not a ten-year battery-life promise. Follow the stated weekly test instruction and applicable smoke-alarm placement guidance.

## In the box

- Smoke alarm (Included)
- 1 9V carbon zinc battery (Included)
- User manual (Included)
- Mounting screws (Included)
- Magnetic fastening kit (Included)

## A good fit for

- Buyers seeking a battery-powered, replaceable-battery smoke alarm with photoelectric sensing and a test/mute button.
- Households wanting the stated low-battery warning and mounting options, including a magnetic fastening kit.

## Less suited to

- Buyers specifically seeking a sealed 10-year battery or a detector that needs no battery replacement.
- Buyers who need a carbon monoxide detector or a hardwired/interconnected alarm, neither of which is specified for this model.

## Customer feedback

Customer feedback reports that buyers appreciate easy mounting, portability, and the detector's loud sound, while experiences with installation and magnetic mounting are mixed. Some also say the battery is not a ten-year battery and find the beeping annoying. That battery concern is consistent with the listing's distinction between a one-year battery and a ten-year product life requiring replacement. Aggregate ratings lean positive overall, but do not establish how well any individual detector performs.
- Positive themes: Customers report that the detector is easy to mount and portable.
- Negative themes: Some customers describe the beeping as annoying and report that the battery is not a ten-year battery.
- Mixed feedback: Feedback on installation and magnetic mounting is mixed, including reports of adhesive not holding and missing magnetic pieces.
- Mixed feedback: Customers describe the alarm as loud, which may be useful for audibility but bothersome in some settings.

## Frequently asked questions

### Does the battery last ten years?
No. The listing says the detector has a one-year 9V battery and describes a ten-year product life with continuous battery replacement.
### What sensing technology does the GS509A use?
The listing identifies a photoelectric sensor and says it is intended to detect slow-smoldering fires that produce light smoke.
### How often should the detector be tested?
The listing says weekly testing is required using the test button.
### What mounting items are listed?
The package contents list mounting hardware with two plastic plugs and two screws, plus a magnetic fastening kit.

## Alternative options

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- [SITERWELL Smoke Detector 9V Battery Operated with Photoelectric Sensor & Low-Battery Warning, Easy to Install Fire Detectors, UL217 10th Edition Listed,GS509A, 4 Packs](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector-4-pack)
- [SITERWELL Smoke Detector 9V Battery Operated with Photoelectric Sensor & Low-Battery Warning, Easy to Install Fire Detectors, UL217 10th Edition Listed,GS509A, 6 Packs](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)
- [SITERWELL Smoke Detector Photoelectric Smoke Alarm 9V Battery Backup \| Hardwired Smoke Detectors Interconnected, Fire Alarms with Test/Silence Button,UL217 Listed Fire Detector,GS562A, 4 Packs](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)
- [SITERWELL Smoke Detector 10 Year Battery Smoke Alarm Fire Detectors \| Photoelectric Fire Alarms with Low Battery & Fault Warning for House Bedroom, UL217 Listed, GS525A, 1 Pack](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)
- [SITERWELL Smoke and Carbon Monoxide Detector Combo 10 Year Battery \| Hardwired Smoke and Co Alarms, Interconnected Co Detectors with Bilingual Voice Alerts For Home,3 Packs](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)
- [Heiman Smoke Detector, Battery Powered Photoelectric Smoke Alarms for Home \| 3 Pack Mini Compact Fire Alarms for Indoor Apartment Rental, Fewer False Alerts, UL 217-10th, 10 Year Battery Operated, S1-S](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)
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## Add-ons

- [First Alert Battery Carbon Monoxide Alarm \| CO400](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)
- [Amazon Basics 8-Pack 9V Long-Lasting Alkaline Batteries for Smoke Detector, Electronics & Audio, Reliable, 5-Year Shelf Life](https://best-deals.pro/visit/siterwell-gs509a-photoelectric-smoke-detector)

## Images

![SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery — 1](https://best-deals.pro/i/wfpAIB2YkVB-8524tufyxjmSFeeABykjSAYpzZf-gc7QK5yE7c6KkcNMV0uTml0fPnavF-OdnP4wk_Yji7-75KgMXhls3vmgLWFo5tXfIrsbZn9OFXx43Smw.jpg)

![SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery — 2](https://best-deals.pro/i/_GbK3DDB-cGtkpiOMAnpKtSVH4tnXXI1PMDnhhbWXuNZPdPxxeq8u4VtjOPE6BNvYqfm9TIMoN_LOmZCNGLcL11nRJy0pC4bJ6twRDJpdKuxov41J_jxawCY.jpg)

![SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery — 3](https://best-deals.pro/i/wbdmGD1-SxucFnHyoKa9vce1EXAAxaqbf1BW8fczoQowNvPLVx9gXiXYU0360PFeiFCo4TKl5eFvODGkdJKeR67Fb3QfdezkA4d82ZjYf8mFVwIXvXBYsyOl.jpg)

![SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery — 4](https://best-deals.pro/i/0Txiiu_bsid1vaMhs1in5p702CLXouQNJJ95An2sMuAMq45I0u1G9mnI7bqblY_V3e2fnQmW5YzUVRqse2h4ljfe3K2XpKd1HWpe2zKkB1fXSOKnMlsJ8Ot1.jpg)

![SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery — 5](https://best-deals.pro/i/rv3e_zcCDWBfaYP2QOX-ciCFvKvSjmNh4HWtWy-FZqc3jLFXly6xWtN7mQ-mC1_Vg6Cq_JxOdhZEyrNT-7EO68D80jSloly8J4A5She5xZUWRGMQZBsjF0KT.jpg)

![SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery — 6](https://best-deals.pro/i/U78QPstd1Rt8VyL5mrY0_tfU3C2JwTNhEnWfhkOh7N1JmCG0n6Ox7ZoeWBIJ7CWLHVnsXP_YCtpo23qAaotQ_jXwiqX0HHCsVRaokszoI4C3FwTrEhYA7bqT.jpg)

![SITERWELL GS509A Photoelectric Smoke Detector, Replaceable Battery — 7](https://best-deals.pro/i/oae_JrO9UflivKhBxgpvSYAlo0psRv13pNSLfJkl7KECxIUp7zUjCSXhLj1YLK7Iaa3qnIWjcT4euWVwa_X9lIIrM23yK500Frz0mgFQBO4zikVY_9P89ucq.jpg)