How to Actually Set Up Infrared Heaters for Fog-Free Mirrors
We’ve all been there. You step out of a hot shower, reach for the mirror to shave or do your makeup, and you’re staring at a wall of white mist. It’s annoying. The fix is pretty simple: we put short-wave infrared lamps behind the glass. The goal is to keep the mirror just warm enough so that the steam doesn’t settle and turn into droplets. But if you just throw any random heater back there, you’re asking for trouble. Getting the wattage right You can’t just guess on the power. A tiny powder room is a completely different beast than a massive master bath with a walk-in shower. If you’re dealing with a small space—something under 5m²—stick with a low-wattage lamp, maybe 50W to 100W. You just want a gentle warmth. If you go overboard here, you’ll end up with “hot spots.” That’s a recipe for thermal stress, which is a fancy way of saying you might crack your mirror. Now, for the big bathrooms (10m² or more), you’ve got way more steam to fight. In those cases, I’d go with 200W to 500W. It keeps the glass warm even when the room feels like a sauna. Where to put the heat Here’s the thing: how you spread the heat matters way more than the total power. Don’t just slap one giant, powerful bulb right in the center. That doesn’t work well. Instead, spread the elements across the surface. It gives you a much more even look. We use short-wave infrared because it hits the glass fast. But keep in mind, more power means more heat leaking back into the wall. Make sure your mounting brackets can handle the temperature. You don’t want to accidentally scorch your drywall. Saving power (and your sanity) You don’t need these things running at full blast 24/7. That’s a waste of money and a quick way to burn out your lamps. Instead, wire them into a timer or a hygrometer relay. That way, the heat only kicks in when the humidity actually spikes. It keeps your electricity bill low and makes the hardware last a lot longer. Simple. Effective. And you can actually see yourself in the mirror.