Decibel Guide for Alarms: Choosing the Right Loudness

When choosing a smart alarm for your home or garden building, you’ll often see the volume listed in decibels (dB). But what does that actually mean? And how loud is “loud enough” when it comes to scaring off an intruder.

What Is a Decibel

A decibel is a unit used to measure sound intensity. It works on a logarithmic scale, which means an increase of just a few decibels represents a significant jump in volume.

Here’s a quick guide to how decibels relate to everyday sounds:

How Loud Should a Smart Alarm Be

It depends on the purpose:

• Indoor alarms (e.g. in a hallway or home office): Around 85–100 dB is usually enough to alert you and deter an intruder.
• Outdoor sirens (e.g. for sheds, garages or outbuildings): You may want something louder, in the 100–120 dB range, especially if it’s meant to be heard across a garden or from inside your home.

Anything over 120 dB is extremely loud and can be painful if you’re nearby.

Loudness vs. Placement

A louder siren doesn’t always mean better protection. An 85 dB alarm mounted at head height near your front door could be more effective than a 120 dB one buried in a loft or inside a cabinet.

Smart Alarms and Custom Volume Settings

Some smart alarms let you adjust the siren volume. This can be useful if:

• You don’t want to wake the whole neighbourhood for a minor event.
• You use different sounds for different alerts (e.g. intrusion vs. water leak).

Test your alarm after setup to make sure it’s loud enough in real world conditions, not just on paper.

Summary

• Decibels measure loudness, but the scale isn’t linear. 100 dB is much louder than 90 dB.
• For smart alarms, anything between 85 and 120 dB is typical.
• Choose the right volume for the setting, and consider how sound will travel through your space.