What is the difference between a smoke alarm and a heat alarm?

So, what’s the difference between a smoke alarm and a heat alarm?

While both are essential in a comprehensive fire safety setup, they detect danger in very different ways—and should be installed in different areas of your home. Understanding these differences helps ensure you’re fully protected from every angle.

In this blog, we’ll break down how smoke alarms and heat alarms work, where to install each type, and why using both gives you the best protection possible.

What is a smoke alarm?

A smoke alarm is designed to detect the presence of smoke in the air—often the first sign of a fire. Most modern smoke alarms in the UK fall into two categories:

Optical  smoke alarms – These are better at detecting slow-smouldering fires, often caused by overheated wiring or soft furnishings.

Interlinked alarms- These are smart alarms that alert you of fire whether it is in that room or elsewhere in the property

For most homes, optical smoke alarms offer the most reliable protection and fewer false alarms.

What is a heat alarm?

A heat alarm detects a rapid rise in temperature or when the room reaches a set temperature threshold (typically around 55°C). Rather than reacting to smoke, it responds to heat, making it ideal for rooms where smoke or steam is common, such as:

• Kitchens
• Garages
• Boiler rooms

Unlike smoke alarms, heat alarms won’t be triggered by burnt toast, cooking steam or dust, making them a smart choice for high-risk but high-activity areas.

What’s the difference between a smoke alarm and a heat alarm?

Still wondering what’s the difference between a smoke alarm and a heat alarm? The key difference lies in how each alarm detects fire. A smoke alarm is designed to sense the presence of smoke particles in the air—typically an early sign of a fire—making it ideal for living rooms, bedrooms, and hallways. In contrast, a heat alarm responds to a rapid rise in temperature or when a room reaches a set temperature threshold, usually around 55°C. This makes it perfect for areas like kitchens and garages, where smoke or steam might otherwise cause false alarms.

Smoke alarms provide an early warning for fires that start with smouldering materials or flames, while heat alarms are more suited to detecting fires that begin with intense heat and little smoke. Using both types together ensures you’re alerted to all kinds of fire risks, giving you more time to escape safely.

Why you need both alarms in your home

Having both smoke and heat alarms ensures you’re covered against all types of fires—whether they start with a visible flame, a slow smoulder, or intense heat. For example:

• A fire in a living room may be detected faster by a smoke alarm.
• A fire starting in the kitchen may not produce much smoke initially but will be picked up by a heat alarm.

By linking your alarms together (with interconnected alarms), you’ll receive an alert throughout the home no matter where the fire starts—giving you and your family more time to escape safely.

Where should I install smoke and heat alarms?

For most homes in the UK, the following layout is recommended:

Smoke alarms in:

• Hallways
• Landings
• Living rooms
• Bedrooms

Heat alarms in:

• Kitchens
• Garages
• Utility rooms
• Lofts

When choosing alarm placement, always follow the manufacturer’s installation guide and check if you’re meeting UK fire safety regulations—especially if you’re a landlord or live in rental accommodation.

Choosing the best alarms for your home

We offer a range of advanced, UK-certified smoke and heat alarms that are designed to keep your home safe and secure. From tamper-proof sealed battery units to smart, connected alarms with remote alerts, there’s a solution for every property type.

Whether you’re replacing old alarms or installing new ones, check out our trusted alarms.