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Professional Guide

Best Carbon Monoxide Detectors for Home Safety: 2025 Expert Review

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Oli

Owner, OR Electrics & 18th Edition Electrician

Published 17 December 2025

Carbon monoxide (CO) is known as the 'silent killer' for a reason. You can't smell it, taste it, or see it. In Leeds, where many of us live in older mix-era properties with gas boilers and fireplaces, a reliable detector isn't just a tick-box exercise—it's a lifesaver.

For landlords, the regulations are strict. You must have a working CO alarm in any room with a fixed combustion appliance. But beyond compliance, I see too many cheap, yellowing units that haven't worked in years. That is a disaster waiting to happen.

In this review, I'm comparing three distinct options: a budget-friendly choice for covering multiple rooms, a trusted industry-standard pack for ultimate peace of mind, and a modern 'sealed battery' unit that solves the headache of constant chirping.

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Specs vs. The Real World

The Spec: "Test Button Function"

The Theory

"Pressing the button confirms the detector detects carbon monoxide."

The Reality

In most units, the test button only checks the battery and internal circuitry, not the actual CO sensor. You must trust the Kitemark and replace the unit strictly by its expiry date.

The Spec: "Placement Anywhere"

The Theory

"You can stick a CO alarm anywhere in the room."

The Reality

CO is slightly lighter than air but mixes easily. Don't put it right next to a window (drafts dilute readings) or behind curtains. It needs to breathe the same air you do.

My Top 3 Recommendations

Three options to cover different needs and budgets

Carbon Monoxide Alarm With LED display, CO Alarms Monitor for Home Safety

Budget Pick
Carbon Monoxide Alarm With LED display, CO Alarms Monitor for Home Safety

USBNOVEL

This unit is an affordable entry point for homeowners needing to cover multiple rooms without breaking the bank. The digital LED display is a standout feature at this price point, allowing you to see low-level CO readings before the full alarm triggers.

Price£8.22 (at the time of writing)
BrandUSBNOVEL
Power Source3x AA Batteries (Not Included)
DisplayLED Digital Screen
The Good
  • Very affordable price point
  • Digital display shows specific PPM levels
  • Simple installation with no wiring required
The Bad
  • Batteries are not included (requires 3x AA)
  • Brand is less recognised than industry giants like Kidde

Installer Tip:

Because this unit requires 3 AA batteries that aren't included, buy quality alkaline batteries (like Duracell) immediately. Don't use cheap heavy-duty ones; they voltage-drop too quickly in cold Leeds hallways.

Priced at £8.22 at the time of writing

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Twin Pack Kidde 5CO Battery Powered Carbon Monoxide Alarm and Detector

Quality Choice
Twin Pack Kidde 5CO Battery Powered Carbon Monoxide Alarm and Detector

Kidde

Kidde is a name us tradespeople trust implicitly. This twin pack is ideal for a standard two-storey terraced home, covering both the boiler area and the sleeping quarters. It holds the BSI Kitemark, which is the gold standard for UK safety compliance.

Price£24.50 (at the time of writing)
BrandKidde
Sensor Life10 Years
CertificationBSI Kitemark (BS EN 50291-1:2018)
The Good
  • Twin pack offers excellent value for whole-home coverage
  • Includes high-quality batteries in the box
  • 7-year warranty and 10-year sensor life
The Bad
  • No digital display (audio alarm only)
  • Functional aesthetic rather than decorative

Installer Tip:

Write the 'Install Date' on the side of these units with a permanent marker before you mount them. It makes it much easier for me (or your landlord) to check if they are still within date during the next inspection.

Priced at £24.50 at the time of writing

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Carbon Monoxide Detector with LCD Digital Display, Sealed 10 Year Battery

Problem Solver
Carbon Monoxide Detector with LCD Digital Display, Sealed 10 Year Battery

XINDUM

The biggest issue with rental properties is tenants removing batteries to stop 'annoying' low-battery chirps. This unit solves that with a sealed 10-year lithium battery. The sleek black design also looks much better in modern apartments or renovated kitchens.

Price£16.99 (at the time of writing)
BrandXINDUM
BatterySealed 10-Year Lithium (No changing required)
MountingFreestanding or Wall Mount (Tapi/Screws)
The Good
  • Sealed battery prevents tampering (great for landlords)
  • No battery changes needed for the life of the unit
  • LCD display for real-time monitoring
The Bad
  • Once the battery dies after 10 years, the whole unit must be replaced (eco consideration)
  • Slightly higher upfront cost for a single unit

Installer Tip:

Use the freestanding option if you are renting and cannot drill holes. Place it on a shelf at breathing height (approx 1.5m up) rather than on the floor or right against the ceiling, for the most accurate detection in living spaces.

Priced at £16.99 at the time of writing

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Frequently Asked Questions

Where should I install carbon monoxide detectors in my home?
You should have one in every room containing a fuel-burning appliance (boiler, gas fire, log burner). It is also wise to fit one in the hallway near bedrooms so the alarm wakes you if a leak occurs at night. In Leeds' multi-storey terraces, I recommend one on every floor.
How often do CO detectors need replacing?
Most sensors last between 7 and 10 years. Check the back of the unit for a 'Replace By' date. If you can't find a date and the unit looks yellow or old, replace it immediately. It is not worth the risk.
Can I use a smoke alarm instead of a carbon monoxide detector?
Absolutely not. They detect completely different things. Smoke alarms detect visible particles from fire; CO alarms detect an invisible gas. You need both to be safe. Some 'combi' units exist, but separate specialised units are often more reliable.
What is the difference between specific alarm brands?
While all sold units should meet safety standards (BS EN 50291), premium brands like Kidde generally offer more reliable sensors that are less prone to false alarms. Budget options work but may have shorter warranties or lack features like digital displays.
Do I need a certificate for my carbon monoxide alarms?
If you are a landlord in Leeds, yes. During your EICR or annual gas safety check, we verify that compliant alarms are present and working. This is a legal requirement for rentals. Contact OR Electrics if you need your property certified.
Is a digital display necessary on a CO alarm?
It is not legally required, but I highly favour it. A display can show low levels of CO (e.g., 30ppm) that might not trigger the full alarm but indicate a developing problem with a boiler or flue, allowing you to fix it before it becomes dangerous.

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