Can You Use Solar Lights Indoors?

Can you use solar lights indoors?

As more and more people are switching to renewable sources of energy, many questions are arising as to renewable energy’s advantages and limits. Solar lights, for example, are a common gray area when it comes to their restrictions.

Solar lights are known primarily for outdoor use, which raises the question, can you use solar lights indoors? Yes, you can use solar lights indoors if the area where the lights will be gets regular sunshine, or if the electrical light in the area is bright enough.

Solar energy does have its boundaries, however, especially when used indoors.

The Limits of Indoor Solar Lights

Solar lights were built mostly for use outdoors or in outer space, where the sun’s rays of light are easily accessible. That does not mean that they cannot be used indoors, however. Indoor solar lights just require some extra rules to ensure they function properly.

Natural sunlight is the most efficient way to charge solar lights, thou artificial light can charge solar lights as well.

Every light source produces a spectrum— a range of light wavelengths that include:

  • Infrared waves
  • Visible light
  • Ultraviolet waves
  • X-rays

Sunlight generates a profuse amount of ultraviolet light, which is what is necessary to charge solar lights. Incandescent bulbs only generate a small amount of ultraviolet light, but it is enough to charge solar lights. It just won’t be the most effective method of charging as it takes much longer to get a full charge from incandescent lights.

Solar lights charged consistently by artificial lights may also eventually lose the ability to properly charge in the long run, so make sure to charge your solar lights using natural sunlight when possible. To lengthen the longevity of your solar lights, only charge them with artificial light sporadically and preferably use incandescent lights, as opposed to LED lights.

Sometimes, the weather may prohibit you from using natural light to charge your solar lights. During winter months when the weather is cloudier, your solar lights, whether indoor or outdoor, most likely will not operate to their full extent. To get the most out of your solar lights during these times, you should strategically place your lights in areas that

  • Receive the most sunlight
  • Are unaffected by shadows
  • Are not obstructed by trees, debris, buildings, and other elements that could possibly cover the lights or produce shadows

When charging solar lights using a light bulb, place the bulb about twenty inches away from the solar panel and let it charge for as long as possible. Depending on the brightness of the bulb, your solar lights may take longer to charge.

Always keep in mind that, though it is better for the environment to use solar lights, using them indoors and having to charge them with artificial light still causes harm to the environment. Be aware of how much electricity you use to charge them and try to find a natural light source— such as near a window— to charge them when possible.

Do Solar Lights Work Through Glass?

Yes, solar lights will work through glass. As long as there is sunlight passing through glass to the solar light, they will work. However, they will not be at their maximum efficiency for a number of reasons.

The first reason is that any sunlight that is reflected off of the glass will be lost to the solar panel and the panel will not be able to charge effectively. The degree of lost sunlight will vary depending on the thickness of the glass, among many other factors, but the solar light will not be able to generate electricity to his full capability.

The second reason is that the angle of the sun’s rays plays a major role in the charging of solar lights. When the sun is at its highest—midday—the charging of solar panels will be most efficient. However, placing solar lights behind glass windows minimizes the potential of getting that efficiency when charging. Window frames, roofs, trees, and other obstructions will decline the rate of charge in your solar panels.

If you must place your solar lights behind windows, be sure to find a window that faces south, if you are in the United States. This will ensure the maximum output of energy from your solar lights as it ensures a more effective charge. Placing your solar lights against a window that faces north will not charge it.

Can LED Lights Charge Solar Lights?

Yes, LED lights can charge solar lights. Although it is faster and more efficient to charge solar lights using incandescent lights, LED lights will charge solar lights as well.

LED lights do not produce the same ultraviolet waves that the sun does, however, so it will take much longer to charge solar panels with LED lights. Using a higher wattage is ideal for charging solar panels so aim for a wattage that is closer to 100.

Can Solar Lights Be Used During Bad Weather?

Many people worry over whether or not their solar lights can withstand extreme weather and often underestimate the durability of solar lights. This underestimation can lead to people bringing their lights inside during bad weather.

Outdoor solar lights can actually work fine in extreme cold and heat, although they work better in the cold, provided there is sufficient sunlight to charge them.

The only causes for concern are weather extremities that may knock them over or damage them, or heavy snowfall that may cover them. If you must bring your solar lights indoors to protect them from the weather, make sure to turn them off and store them in a cool environment.

When using solar lights during the winter months, you want to be sure to clear any snow off of the panel using a cloth or brush with soft bristles. This will guarantee that the solar panels can collect the most sunlight necessary for its charge.

Glass solar lights are more susceptible to damage, such as breaking, due to bad weather. Make sure your glass solar lights are well protected during bad weather by securing them to prevent them from falling or by bringing them inside. Heavy rain or snowfall may also break glass solar lights, so be sure they are well protected.

Can Solar Lights Charge on Cloudy Days?

Even though there is much less sunlight on cloudy and rainy days, there is still enough light to charge solar panels. The clouds may block some of the sunlight but your solar lights will still receive a charge.

However, your solar lights will not be getting a full charge. Less sunlight on cloudy days means your solar lights will only get 1/2 to 1/3 of its maximum charge. Therefore, your solar lights will only work a fraction of the time, as well.

If there are multiple cloudy days in a row, your solar lights should still work most of the time due to the batteries’ storing capability of power. However, if your solar lights go many days without a full charge, it can lead to damage in your solar lights’ lifespan and efficiency.

It may be a good idea to temporarily turn your solar lights off if the weather is predicted to be gloomy for a few days at a time. If you live in an area that consistently has bad weather, you may also want to switch out your solar lights periodically to prevent long term damage to them. Luckily, when sunny days come back, your solar lights will fully charge and will work just fine. Just be sure, if you turned your solar lights off, to turn them back on and make sure they are cleaned.

Title image by Matthew Newcomer


Hi I'm Harris the spgenie! As an engineer, I found myself doing tons of research about solar power, the types of panels, how to store the energy and the best way to finance the project. I thought I'd start this blog to share my findings. I hope you find this useful.

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