#1 Home Improvement Retailer

Internet #100594387

Model #21029895

Store SKU #146421

Store SO SKU #1000497860

Firex Hardwired Inter-Connectable 120-Volt Auxiliary Heat Detector 135 Degree with Battery Backup

Apply Now
Pay $14.97 after $25 OFF your total qualifying purchase upon opening a new card. info
Apply for a Home Depot Consumer Card
  • Heat alarm requires hardwire installation
  • All interconnected alarms will sound when one alarm goes off
  • Best for pitched elevated heat areas such as ceilings and attics
  • View More Details
0 in stock
Text to Me
How to Get It

Frequently Bought Together

Best Seller

Product Overview

The Kidde FireX HD135F is a 120-Volt AC Wire In Heat Alarm that responds to temperature rather than smoke. The alarm will sound if temperatures rise above 135 degree F. The Kidde HD135 degree F is inter connectable. The interconnect system must not exceed the NFPA (National Fire Protection Association) limit of 18 initiating devices (Smoke, heat, CO, etc.) interconnected, it is still possible to interconnect 6 strobe lights and or relay modules. This unit includes a 5-year limited warranty and is UL Listed.
  • Receive an instant alert when temperatures exceed 135 degree F
  • Test button assures proper operation of the sensor's electronic circuitry, horn and battery function
  • Interconnects with up to 24 Kidde devices (of which 18 can be initiating), including smoke and carbon monoxide alarms
  • 9-Volt battery backup provides continuous protection even during power outages
  • Red LED flashes every 30 - 40 seconds to indicate proper operation
  • Quick-connect power harness for fast and easy installation
  • Tamper-proof pin helps deter tampering and theft
  • Replacement 9-Volt battery Kidde model 21025830
  • UL/CSFM Ref. HD135F
  • Not a smoke detector
  • Compatible with Kidde, FireX, Code One and Sentinel products
  • Kidde offers a full range of 120-Volt AC wire-in life safety products with interconnect capability to provide the most immediate and complete system available; when any 1 interconnected alarm is triggered, all interconnected alarms within the home sound an immediate warning
  • Learn how to install a smoke alarm
  • UL/CSFM Ref. Kidde Part HD135
  • Click here for more information on Electronic Recycling Programs

Additional Resources

From the Manufacturer

Questions & Answers

Typical questions asked about products:

  • Is the product durable?
  • Is the product easy to use?
  • What are the dimensions of the product?

Customer Reviews

  • 4.6
    out of 95 reviews
  • 97%recommend this product
Filter by:
Showing 1-10 of 95 reviews
The Kidde Heat Alarm was easy to install. Only took...
The Kidde Heat Alarm was easy to install. Only took about 5 min. to take down the old one and put in the new one. Also, came with a 9 volt battery which was nice. Nicely packaged and fast delivery. Didn't realize they recommend changing out detectors every 10 years.
  • Verified Purchase
No more false alarms.
Fumes from my Street Rod would set off my house alarm,usually at 2 or 3 AM. My son in law (ex Firefighter) told me the make heat detectors. I bought one online and it was plug and play. Took just a couple minutes to install. No false alarms since then.
  • DIY
  • Verified Purchase
  • Recommended
1 found this review helpful
  • Verified Purchase
  • Verified Purchase
The battery not have charger...
The battery not have charger
Response from Kidde ExpertMay 12, 2022
Hello. No. The unit does not charge the battery. It has to use a 9 volt alkaline battery that has to be changed every 6 months to a year. More information can be found in the owner's manual and by calling us at 1-800-880-6788
  • Verified Purchase
  • Verified Purchase
Very easy to install...
Very easy to install
  • Verified Purchase
Great product easy to install...
Great product easy to install
Response from Kidde ExpertMar 15, 2022
Hello. We appreciate the praise. Call us at 1-800-880-6788 if there are ever any issues or questions we can help you with or anything we can do for you.
  • Verified Purchase
Perfect for garage/ADU
Mine is installed in the garage where you can’t use smoke/co2 detectors. It is interconnected to the apartment’s smoke and co2 which is built above the garage. If there’s ever a fire in the garage, it will give us ample warning to get out of the apartment theoretically. I’d like to see a smart version of this sensor to integrate with the smart devices that are available.
Response from Kidde Product SupportFeb 22, 2022
Hello. Thank you for your review and suggestion. We will pass that along. Let us know at 1-800-880-6788 if there are questions or issues we can hep you with.
    • Recommended
    • Verified Purchase
    Showing 1-10 of 95 reviews