Many homeowners ask the same question: are smoke alarms also carbon monoxide detectors? While both devices are essential for home safety, they serve different functions—and in most cases, a smoke alarm will not detect carbon monoxide.
This article explains the difference between smoke and carbon monoxide (CO) alarms, what each is designed to detect, and why it’s important to have the right alarm in the right location.
What Does a Smoke Alarm Do?
A smoke alarm is designed to detect visible smoke particles in the air, usually a sign of a fire. Most alarms used in New Zealand homes are photoelectric, which means they use a light sensor to pick up smoke caused by slow, smouldering fires.
Smoke alarms should be installed in all bedrooms, hallways, and living areas. They’re a legal requirement in New Zealand homes and are your first line of defence in case of fire. However, they do not detect carbon monoxide.
What Does a Carbon Monoxide Alarm Do?
Carbon monoxide is a toxic gas that has no colour, taste, or smell. It is produced when fuels such as gas, wood, coal, or oil burn incompletely. Faulty heaters, fireplaces, or gas appliances can cause CO to build up indoors.
Carbon monoxide alarms are designed to detect this gas before it reaches dangerous levels. They trigger an alert if carbon monoxide is present, giving you time to ventilate the area or evacuate. These alarms are not designed to detect smoke or fire.
How Are Smoke and CO Alarms Different?
While both alarms enhance home safety, they are designed to detect different types of hazards:
- A smoke alarm detects particles from fires.
- A carbon monoxide alarm detects gas produced by incomplete fuel combustion.
They also differ in where and how they should be installed. Smoke alarms are best placed in sleeping areas, hallways, and living rooms. CO alarms should be installed near gas appliances, wood burners, or in rooms where fuel is used for heating. In some homes, such as those with an attached garage or fireplace, both types of alarms may be necessary.
It’s important to note that standard smoke alarms do not detect carbon monoxide unless they are specifically built as combination alarms.
Are There Alarms That Detect Both Smoke and CO?
Yes, some models combine smoke and carbon monoxide detection in a single unit. These combination alarms can be convenient for homeowners who want a single device in areas where both risks exist. However, they must be installed carefully to meet both smoke and CO placement guidelines.
Currently, CAVIUS focuses on high-quality smoke and heat alarms. We recommend installing a separate carbon monoxide detector if your home contains any of the following:
- Gas heaters or cooktops
- Wood-burning fireplaces
- Fuel-burning appliances
- An attached garage
Should You Have Both Types of Alarms?
If your home uses fuel-burning appliances or heating, the answer is yes. A smoke alarm alone won’t detect carbon monoxide, and a CO alarm won’t alert you to smoke or fire. Both hazards pose serious risks, but each requires a specific type of sensor to detect it.
Together, smoke and CO alarms provide more complete protection for your home and family.
Where to Go for More Help
If you’re unsure whether your existing alarms provide adequate protection, start by checking the labels. Smoke alarms will typically state that they detect smoke only, while carbon monoxide alarms will clearly mention CO detection.
Final Thoughts
To answer the question, are smoke alarms also carbon monoxide detectors? — in most cases, they are not. Smoke alarms detect fires, while carbon monoxide alarms detect invisible gas threats. For complete home safety, it’s recommended to install both where appropriate.
To learn more about alarm types, proper placement, or maintenance, explore the CAVIUS blog or contact us for guidance.