Electric Mirror Defogger Install Tips and FAQs

Mirror defoggers are a great addition to any bathroom. They’re low cost and use very little electricity, with the smallest unit we sell generating only 41 watts. The largest mirror defogger we sell (30” x 40”) draws only slightly more than an incandescent lightbulb or desktop computer at 150 watts.  

Our ClearlyYou mirror defogger is a plastic sheet with an electric filament “printed” onto its surface. It works much the same way a defroster on a rear car window does. Voltage (120 VAC) is run through the resistant filament, producing wattage (heat), that heat is then transferred through the glass to warm the surface, which makes it too warm for condensation to form.

Installation is straightforward and detailed instructions are provided. Keep in mind that all wiring must be in accordance with the National Electrical Code (NEC) and should be performed by a licensed professional who is certified to do electrical wiring. Prior to wiring your defogger, make sure that the electrical circuit breaker is shut off at the main panel. These defoggers are not rated for wet areas, so please, no saunas, showers, or steam rooms. 

Always check the mirror defogger for damage before installation. Creases, tears, or other obvious damage may cause the unit to malfunction. If you received a mirror defogger that is damaged, please give us a call, and we can issue a replacement. Never overlap the mirror defoggers if using more than one unit on a mirror. The mirror defoggers should not be cut or resized. As always, use caution and follow the instructions, and everything should fall into place nicely.

Introduction to WarmlyYours ClearlyYou™ Mirror Defoggers

Pro Tip: By wiring the mirror defogger to the lighting above the vanity, the mirror defogger will automatically turn on whenever you turn on your vanity lighting. The mirror defogger will begin to defog within 5 minutes of operation.

Please be advised the mirror may crack under the following conditions.

• If there is no gap between the mirror and hard substances.
• If there is tile or marble around the perimeter of the heated mirror, the mirror may crack during heating because there is not enough room to allow for the expansion of the mirror. A 2mm gap around the perimeter of the mirror is required to allow for this expansion.
• If a mirror is held in place by a nail or other rigid mounting materials, ensure that there is room for expansion around the other 3 edges. The mirror may crack if trapped between the mounts and other hard objects.
• The following are three examples of mirror cutting that may cause the mirror to crack: 
  • A rectangular hole for a switch, outlet, or appliance. 
  • Any hole exceeding a diameter of 2” (50mm) (which is common for plumbing). 
  • Any inner angles cut into the mirror.

Frequently Asked Questions

Q: Can you attach it to the back of a medicine cabinet door?

A: No. Mirror defoggers are designed to be mounted and wired to a fixed, wall-mounted mirror.

Q: Can I put a mirror defogger in my shower?
A: No. Mirror defoggers are not rated to be installed in wet locations like shower enclosures.

Q: Can I trim the mirror defogger?
A: No. Mirror defoggers can't be trimmed, and the proper size needs to be selected to fit on an open, unobstructed area on the back of the mirror.

Q: Can I use multiple defoggers on the same mirror?
A: Yes, but please make sure not to overlap multiple heating elements over each other.

Q: Can I wire it to the lighting circuit?
A: Yes. This is the most common way to operate a mirror defogger.

Q: What is the length of the cold lead for a mirror defogger?
A: A mirror defogger cold lead is 36 inches long.

We hope these tips and tricks helped answer any questions you might have had, but if not, feel free to leave us a comment below or contact us via chat, phone, or email (info@warmlyyours.com).