The more windows your house has, the more efficient your indoor lighting system will be. (This goes for skylights as well.) That's because the sunlight that enters through the glass can serve a purpose rather than simply being a nuisance. Here are three reasons why adding more windows and skylights can increase efficiency and eco-friendliness.

1. Natural lighting can reduce your contribution to the urban heat island effect

"Cool roofs" and other cooling efforts for green living, such as reflective paint for your walls, try to ameliorate the impact of human settlements on the surrounding environment in several ways. First, they reduce the amount of electricity needed to keep you comfortable in the summer (which is significant because if your AC is on the grid, you're probably using up fossil fuels because most big power companies in the US still use fossil fuels to power the grid).

Second, they reduce the urban heat island effect, which is the cumulative effect of the man-made surfaces (especially asphalt) that soak up sun in a given area. They hold the thermal energy and release it slowly at night rather than turning it into energy like plants do. This means that they raise the overall temperature of the area by an appreciable amount. The storm water runoff is also warmer, which can affect the streams and rivers where it drains. As you can see, reducing this effect can reduce the negative impact of human settlements on nearby ecosystems.

2. It won't bounce off as light pollution

In addition to reducing energy used for cooling and minimizing the urban heat island effect, cool roofs actually also do something else that many consider to be polluting: they reflect light back into the atmosphere. Some feel that this could have unintended consequences such as increasing light pollution or even reducing cloud formation, although there are no scientific studies to prove this.

Plus, if you put a super-reflective roof on a short building, it could reflect heat and light through the windows of a nearby taller building, effectively passing your energy bills off onto your neighbor (which not only means a reduction in overall efficiency, but also means your neighboring tall buildings aren't going to be happy with you). So letting the light in and using it as natural lighting as much as possible can help reduce the dilemma of how to deal with the sun that beats down on your roof each day.

3. It means you use less energy for artificial light

Letting natural light in can significantly reduce your need for artificial light. And if you have a lot of large windows and/or skylights, you may be able to only turn on artificial lights after nightfall. If you play your cards right, you can reap these benefits of sunlight without any of the negative side effects; simply use window coatings that allow the visible light through and block the UV rays.

As you can see, extra windows and skylights can allow you to make use of sunlight as an interior lighting solution, rather than having to reflect it all back into the atmosphere or letting it simply soak into your roof. Click here to learn more about window installation.