Costs, reliability, disruption and compliance compared, with advice on when a wireless or hybrid system makes more sense.
The short answer
Wired fire alarms cost less per device and suit new builds and major refurbishments. Wireless fire alarms cost more per device but are much quicker and less disruptive to fit, so they suit occupied buildings, listed buildings and temporary sites. Many buildings use a hybrid of both.
Both types can be fully compliant with BS 5839-1 when they use approved equipment and are designed, installed and maintained properly. Wireless devices must meet BS EN 54-25 for radio-linked fire alarm components. The right choice depends on the building, how it is used and how much disruption you can accept.
Wired fire alarms
Detectors, call points and sounders are connected to the control panel with fire-resistant cable. Wired systems can be conventional (zoned) or addressable (each device has its own address so the panel shows exactly where the alarm is).
Wireless fire alarms
Devices communicate with the panel by radio, usually through a mesh network where devices pass signals to each other. Only the panel and a few translator or expander units need a mains connection.
Hybrid systems
A hybrid system uses wired devices where cabling is easy, such as corridors and plant rooms, and wireless devices where it is not, such as decorated rooms, high ceilings or extensions. It is often the best balance of cost and disruption, especially when extending an existing wired system.
Which is cheaper overall?
For a new build, wired is usually cheaper. For an occupied or historic building, wireless often works out similar or cheaper overall, because the labour, making good and lost trading time are much lower, even though each device costs more. We price both options where it makes sense so you can compare.
Maintenance
Both types need servicing at least every six months under BS 5839-1 (see how often a fire alarm needs servicing). For wireless systems the engineer also checks signal strength and battery levels, and replaces device batteries in line with the manufacturer’s guidance.
Salts Fire & Security designs and installs wired, wireless and hybrid fire alarms and is BAFE SP203-1 registered. See our fire alarm service, or find us in Bradford, Leeds, Ilkley, York and beyond.
Common questions
Are wireless fire alarms as reliable as wired?
Yes, when they use BS EN 54-25 approved equipment and are designed after a proper radio survey. Devices are monitored constantly and report faults such as low battery or signal loss to the panel.
Are wireless fire alarms compliant with BS 5839-1?
Yes. Wireless systems can fully comply with BS 5839-1 if the equipment meets BS EN 54-25 and the system is designed, installed and maintained to the standard.
How long do wireless fire alarm batteries last?
It depends on the manufacturer and the device, but batteries typically last several years. They are checked at every service and replaced as recommended.
Can wireless devices be added to my existing wired system?
Often, yes. Many addressable panels support wireless expanders, so you can extend a wired system into new areas without running new cable.
Is a wireless fire alarm good for a listed building?
Yes. Wireless systems need very little cabling, which helps protect historic fabric and usually makes listed building consent simpler.
How long does a wireless fire alarm installation take?
Much less time than wired. Many small and medium buildings can be done in one or two days with the building still in use.
Last reviewed 04/11/2026 by the Salts Fire & Security team, Baildon. This is general guidance; your fire risk assessment and the full standard take priority.
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