# First Alert SMI100 Smoke Alarm

*Published: 2025-05-17 | Updated: 2025-07-18 | Source: https://shopsavvy.com/products/first-alert-smi100-smoke-alarm*

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**Brand:** First Alert
**Price Range:** $15.47 - $129.99 across 4 retailers

## Pros
- Battery replacement is convenient without needing to remove the unit from the ceiling.
- Offers a simplified installation with matching screw holes and convenient side-loading battery door.
- Loud alarm sound ensures effective alerting.
- High-quality construction and effective performance.
- Compact size and design make it easy to store in small spaces.
- Users report positive experiences leading to repurchases.
- Good value for the price with confidence in its longevity due to the 10-year battery life.

## Cons
- Instructions have small font, making them difficult to read.
- Online manual lists a different model number, causing confusion.
- Batteries included are not functional and are nearing expiration with a December 2023 date code.
- Challenging to secure the unit properly due to a tricky cover and loose screw-on design.
- The design could be more user-friendly, such as including a ratcheting base.
- The plastic locking mechanism requires a screwdriver, which is not intuitive for users.

## Specifications

| Attribute | Value |
|-----------|-------|
| Country/Region of Manufacture | Mexico |
| Power Source | Battery |
| Battery Included | Yes |
| Manufacturer Warranty | 10 years |
| Item Depth | 2 in |
| Item Diameter | 5.6 in |
| Year Manufactured | 2024 |
| Item Width | 5.6 in |
| Operating Sound Rating | 100 dB (123) |
| title | First Alert SMI100, Battery-operated Smoke Alarm, 1-Pack |

## About This Product

The First Alert SMI100 Battery-Operated Smoke Alarm is equipped with First Alert's Precision Detection advanced sensing technology and meets new industry standards. This battery-operated smoke alarm is easy to install and the front access battery compartment makes for easy battery replacements.

## Last Seen Prices

| Retailer | Price | Availability | Last seen | Store's standard terms |
|----------|-------|-------------|-----------|------------------------|
| [retailers/amazon](https://shopsavvy.com/api/redirect/products/e0caf891-b515-071c-5e6d-a03742e98168/offers/cc3b9248-f50d-f842-d090-7728cda7236a?source=shopsavvy&medium=product-page) | $15.47  | In Stock | 2025-05-17 (may have changed) | 30-day returns (in store too) |
| [retailers/kateminimalist](https://shopsavvy.com/api/redirect/products/e0caf891-b515-071c-5e6d-a03742e98168/offers/39a90d5a-31cc-b876-428b-00c6be4b1f5c?source=shopsavvy&medium=product-page) | $43.49  | In Stock | 2025-05-17 (may have changed) |  |
| [retailers/shopstyle](https://shopsavvy.com/api/redirect/products/e0caf891-b515-071c-5e6d-a03742e98168/offers/c3ec8c77-e492-8c29-82cf-8f7bbb549e59?source=shopsavvy&medium=product-page) | $51.99  | In Stock | 2025-05-17 (may have changed) |  |
| [Best Buy](https://shopsavvy.com/api/redirect/products/e0caf891-b515-071c-5e6d-a03742e98168/offers/d78f37f8-9a0d-1543-1ecb-cae7b5f19a82?source=shopsavvy&medium=product-page) | $129.99  | In Stock | 2026-07-22 (may have changed) | 15-day returns (in store too) · free return shipping · free shipping on $35+ |

*Store terms are each retailer's standard return and shipping policy from ShopSavvy's retailer research; some products and categories differ, so check with the store before buying.*

[See every retailer and the full price history on ShopSavvy](https://shopsavvy.com/products/first-alert-smi100-smoke-alarm)

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*About this page: ShopSavvy compares prices across thousands of retailers, aggregates expert and user reviews, and tracks price history to help you make informed buying decisions. Prices are collected from retailer listings; the Current Prices table shows the date each price was last seen.*

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