The world’s first patented smoke detector? Believe it or not, it used butter. In 1902, English engineer George Andrew Darby placed a block of butter between two metal plates. When it melted, the plates touched, completed a circuit, and rang a bell. It was crudeб but effective.

Thankfully, we’ve come a long way since then. In the 1960s, American inventor Duane Pearsall introduced the first mass-market, battery-powered smoke alarm: the SmokeGard 700. Compact, affordable, and mess-free, it brought fire safety into homes around the world.



Today’s smoke detectors are more advanced — but they still follow one simple rule: they only work if they’re installed and maintained.

How Smoke Alarms Work

Modern detectors typically use two technologies:

Ionization

These models have a tiny amount of radioactive material between two electrically charged plates. This ionizes the air, allowing a current to flow. When smoke enters the chamber, it disrupts the flow — and the alarm goes off. Ionization models are especially good at detecting fast, flaming fires.

Photoelectric

These use a light beam pointed across a sensor. When smoke drifts into the chamber, it scatters the light into the sensor, triggering the alarm. Photoelectric alarms are excellent at detecting slow, smouldering fires.

“Because each type reacts to different fire conditions, the best choice is a dual-sensor alarm that includes both technologies,” says Bob Hillier, Owner of Paul Davis Restoration of Greater Houston. “Most models today are dual-type — but double-check the label before you buy.”

Installation and Maintenance Matter Most

Even the best smoke alarm can’t save lives if it’s not installed or working. Here’s what you need to do:

Install at least one alarm per level of your home, including every sleeping area.

Test them monthly.

Change batteries every year, unless you have sealed 10-year models.

Clean detectors with a vacuum or dry cloth — dust can block sensors.

Replace all units every 10 years, even if they seem fine.

Hard-wired smoke alarms, which are wired into your home’s electrical system, are now standard in many Canadian homes. These models often include battery backups and can be interconnected — if one sounds, they all do.

A Simple Device That Saves Lives

“Roughly 60% of fatal house fires happen in homes with no working smoke alarms,” says Hillier. “It’s not about the brand or the technology — it’s about having them, testing them, and replacing them when needed.”

📞 Have questions about fire safety in your home? Call Paul Davis Canada at 1-800-661-5975.