Free Delivery on 100s of Products

Live Chat - Online Instant help & advice

Trade Discounts & exclusive pricing

Secure Payments with our fast checkout

0% Credit Available Apply for an account

Mains Powered Smoke Alarms & Heat Alarms with Alkaline Back-up Battery - Firehawk BB Series

Front view of the firehawk mains smoke alarm alkaline battery showing a round white device with a small vent area
5 out of 5 stars

End of Line

£19.58 inc VAT

£16.32 ex VAT

The FHN250BB optical smoke alarms and FHN450BB heat alarms from Firehawk are mains-powered alarms with hardwire interlink, allowing up to 15 compatible alarms in the house to sound a warning to occupants when one detects a possible fire. These models feature replaceable AAA alkaline back-up batteries to ensure continued fire detection during a power cut, or if mains-power is turned off for other reasons like decorating or a blown light bulb. The unique Fast-Fix mounting base design allows alarms to be easily removed for cleaning and replacing batteries without needing to cut the power or worry about wiring, and the alarms will chirp an "end of life" warning (which can be silenced overnight) when the whole unit needs replacing after 10 years.

  • 230V mains powered with alkaline battery backup
  • 3 x AAA alkaline battery backup (included)
  • 6 year manufacturer's warranty
  • Available in two versions:
    • FHN250BB optical smoke alarm – suitable for most rooms including hallways, landings, living rooms, and bedrooms
    • FHN450BB heat alarm – suitable for rooms likely to have steam, dust, or fumes like kitchens and garages
  • Also available with lithium back-up batteries that last the full 10 year life of the alarms
  • Fast-Fix design for quick installation using Push-Fit connectors
  • Up to 15 Firehawk FHN mains-powered smoke and heat alarms can interlink in one system
  • Advanced sensor technology to ensure quick detection of fires and reduced false alarms
  • End of life warning chirp can be silenced up to 10 hours
  • Combined large test and silence button for ease of maintenance
  • Suitable for installations complying to
  • CE marked and certified to (smoke alarm) / Kitemarked to (heat alarm)
  • This alarm is also suitable for the updated 2022 Scottish legislation for fire alarms in homes

Please Note: these FHN series alarms are not compatible with the older FH models.

Customer Reviews

Customer Reviews (3)

5 out of 5 stars

Reviews by Real Customers

All of our product reviews are written by real customers that have purchased this product from us and are published without modification.

Rating: 5 / 5

Reviewed by

M R

Published on

11th May 2026

Excellent and easy to install.

Applies to option(s): Heat Alarm

Rating: 5 / 5

Reviewed by

K M

Published on

1st January 2026

The heat alarm links to the fire alarms.

Very pleased with these products.

Applies to option(s): Heat Alarm

Rating: 5 / 5

Reviewed by

S D

Published on

30th March 2023

As promised. Very easy to install as a replacement.

Very good value for money and comes with an excellent provenance.

Applies to option(s): Heat Alarm

FAQs

There are no FAQs to display for the selected item.

Technical Data

Technical Data

Product Code FIFHN250BB
Brand Firehawk
Back-Up Battery Type Alkaline
Battery Type AAA Batteries
British Standard Grade Grade D2: Mains Powered (replaceable backup)
Colour White
Local Legislation Scottish Legislation (2022)
Welsh Legislation (2022)
Approvals & Markings CE Marked
UKCA Marked
Compliance BS 5839-6
BS EN 14604: 2005
Connection Wired
Display LED Indicators
Environmental Suitability Indoors
Fixing Options Screws (included)
Installation Position Ceiling
Material Plastic
Maximum Number of Linked Devices 12 Devices
Operating Temperature 0°C To +40°C
Positioning Bedrooms
Hallways
Landings
Living Rooms
Power Type Mains Powered (230V)
Product Range FireHawk FHN Series
Relative Humidity Less Than 85%
Recyclable Yes - Valpak's WEEE Distributor Take-back Scheme
Sensor Type Optical
Sound Level 85dB
Suitability Home
Warning Type Audible - Alarm Sounder
Warranty 6 Years
Dimensions (Unit)
  • Depth: 55mm
  • Diameter: 113mm
Weight 196g
Datasheets
Interlink

Interlink

Please Note: these FHN series alarms are not compatible with the older FH models.

Product Code Description Interlink Type
FIFHN250BB Mains Smoke Alarm with Alkaline Battery Backup Hardwire Interlink
FIFHN450BB Mains Heat Alarm with Alkaline Battery Backup Hardwire Interlink
FIFHN250RB Mains Smoke Alarm with Lithium Battery Backup Hardwire Interlink
FIFHN450RB Mains Heat Alarm with Lithium Battery Backup Hardwire Interlink