Replacement for Kidde KF10 Mains Powered Smoke Alarms
The Kidde KF10 is a mains-powered smoke alarm with a 9V backup battery and the ability to interlink with other Firex KF Series alarms via a hardwired connection. As the ionisation-based KF10 has been discontinued by Kidde, the recommended replacement is the KF20. The KF20 offers the same key features and is fully compatible with the existing base plate and connector, making it a direct upgrade. Using modern optical sensing technology, it provides a simple, electrician-free replacement for existing KF10 installations.
Optical smoke detection is much less susceptible to false alarms from everyday fumes such as cooking vapours and natural humidity. This makes them ideal for installation in hallways, bedrooms, landings, and living areas
- Power: 230V mains powered with battery backup
- Back-up Battery: 9V alkaline battery
- Warranty: 6 year warranty
- CE marked and Kitemarked to BS EN 14604: 2005
- Suitable for installations complying to BS 5839-6: 2019 Grade D2
- Combined Test / Hush button
- Low battery warning chirp – Silence for 8 hours for a peaceful night
- Supplied with fixings and a coloured dust cover (ideal for use when decorating)
- This alarm is also suitable for the updated 2022 Scottish legislation for fire alarms in homes
Customer Reviews (19)
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.
Reviewer
M P
Published on
20th January 2026
Reviewer
S P
Does as says!
Published on
17th October 2025
Reviewer
A R
Excellent service right product.
Published on
19th January 2025
Technical Data
| Product Code | KEKF20 |
|---|---|
| Brand | Kidde |
| Manufacturer's Part Number | KF20 |
| Approvals & Markings | CE Marked |
| Back-Up Battery Type | Alkaline |
| British Standard Grade | Grade D2: Mains Powered (replaceable backup) |
| Colour | White |
| Compliance | BS 5839-6 |
| BS EN 14604:2005 | |
| Connection | Wired |
| Display | LED Indicators |
| Fixing Options | Screws (included) |
| Installation Position | Ceiling |
| Local Legislation | Scottish Legislation (2022) |
| Welsh Legislation (2022) | |
| Material | Plastic |
| Maximum Number of Linked Devices | 24 Devices |
| Operating Temperature | 0°C To +40°C |
| Positioning | Bedrooms |
| Hallways | |
| Living Rooms | |
| Power Type | Mains Powered (230V) |
| Product Range | Kidde Firex |
| Recyclable | Yes - Valpak's WEEE Distributor Take-back Scheme |
| Relative Humidity | Up To 93% |
| Sensor Type | Optical |
| Sound Level | 85dB |
| Suitability | Home |
| Warning Type | Audible - Alarm Sounder |
| Warranty | 6 Years |
| Dimensions (Unit) |
|
| Weight | 280g |
Replacement Compatibility
The table below shows the Kidde smoke alarms which can be replaced by the KF20 optical smoke alarm when they reach the end of their 10 year lifespan.
| Model Number | Description | Installation |
| KF10 | KF10 Ionisation Smoke Alarms with Alkaline Backup | Simple swap – no electrician needed |
| KF10R | KF10R Ionisation Smoke Alarm with Lithium Backup | Requires connector to be swapped by electrician |
| KF1 | KF1 Ionisation Smoke Alarm with Alkaline Backup | Simple swap – no electrician needed |
| KF1R | KF1R Ionisation Smoke Alarm with Lithium Backup | Requires connector to be swapped by electrician |
| 4870 / 4881 | 4870 and 4881 Ionisation Smoke Alarm | Simple swap – no electrician needed |
| 1240C / IAR230C | 1240C and IAR230C Ionisation Smoke Alarm | Simple swap – no electrician needed |
| 123i / 1239HI | 123i and 1239HI Ionisation Smoke Alarm | Requires connector to be swapped by electrician |
| 1275H | 1275H Ionisation Smoke Alarm | Requires connector to be swapped by electrician |
Perfect product, as described - fitted directly into the old ceiling fittings with no hassle.