Solar Window Candles: Do They Work for Christmas Windows?

Solar window candles work for Christmas windows when they sit in a window that gets several hours of direct winter sun. The panel charges through the glass at lower output, so south-facing windows without tinted glass or shade work best. In north-facing or shaded windows, battery window candles with a timer are the dependable choice.

Candles in the window are an old American Christmas look, and solar versions promise it without cords or battery changes. This page explains how they charge, which windows suit them and when a battery candle is the better buy. For outdoor solar sets, see our hub on the best solar Christmas lights.

How solar window candles charge and switch on

Solar window candles carry a small solar panel and a rechargeable battery, and a light sensor turns the flame tip on at dusk. Touch of Eco’s Carolite candles are listed as turning on automatically every night and charging each morning. Retail listings give these specs:

The listings give no brightness figure, so expect a soft accent glow rather than a reading light. Check any other model’s listing for the same specs before you buy: charge time, run time, battery type and whether the battery can be replaced.

Do solar window candles charge through window glass?

Solar window candles do charge through window glass, but less than they would outdoors. PowerFilm Solar, a solar panel maker, says a panel behind a window still produces power at lower output. Its explanation is that glass filters part of the light a panel uses, and low-E coatings reflect infrared energy.

Vitro, a glass maker, explains that low-E coatings are built to reflect infrared heat while letting visible light through. PowerFilm notes that amorphous silicon panels collect mainly visible light, which passes through glass more easily than infrared. That suits window candles, since the Carolite lists an amorphous silicon panel.

What cuts the charge most indoors:

• Tinted, laminated or filmed glass. PowerFilm says tinting and lamination limit light further.
• Screens and storm windows. A screen or a second pane adds shade and another surface.
• Angle. Sun striking glass at a slant reflects more of its light, and the low winter sun may sit below the top of a deep window frame.
• Curtains and blinds. Closed during the day, they block the panel entirely.

Which windows suit solar window candles in December

South-facing windows suit solar window candles best in December. PowerFilm Solar says south-facing windows perform best behind glass, though still short of outdoor output. East-facing windows produce more early in the day and then drop off, and north-facing windows rely on diffuse light and produce very little. PowerFilm puts east and north-facing windows at often 7 to 15 percent of outdoor output.

December sun is weak to begin with. The U.S. Department of Energy notes that Denver gets nearly three times more solar energy in June than in December.

A house with candles in every front window often has windows facing more than one way. A mixed set solves that: solar candles on the sunny side, battery candles with timers on the other.

Battery window candles with timers as the backup

Battery window candles with a timer are the backup for any window a panel cannot charge in. 612 Vermont’s VT-1506 window candles, for example, take 2 AA batteries per candle and have an automatic timer that keeps them on for 6 hours and off for 18, repeating daily. The maker estimates about 40 days of battery life.

Because a timer candle repeats its cycle every 24 hours, switch it on at dusk and it comes on at about that time each evening. A solar candle turns on when its sensor sees dark, so its start time follows the sunset. For more on how built-in timers behave, read our page on solar lights with remote and timer modes. For a wider look at lights that need no outlet, see Christmas lights without electricity.

Why flameless window candles beat real ones

Flameless window candles keep an open flame away from curtains, and that is the main reason to choose them. An infographic from the U.S. Fire Administration and NFPA says almost half of December home decoration fires are started by candles, and that Christmas is the peak day for candle fires. The U.S. Fire Administration suggests considering battery-operated flameless candles and keeping any real candle at least 12 inches from anything that burns.

Window candles have used electricity for a long time. The Colonial Williamsburg Foundation says its candles in the windows began with the restoration in the 1930s as part of an old-fashioned Christmas, drawing on the old custom of lighting windows for special occasions. Staff first watched real candles through the night, and the town moved to electric candles in the 1940s. Solar is the newest step: the same glow, with no cord to the outlet under the sill.

For outdoor solar lights that run longer than a small window candle, our page on how long solar Christmas lights stay on sets out run times, and the balcony and apartment guide covers renters with only a window or railing to work with. To light the whole front of the house from one stake, see solar Christmas projector lights.