Daylighting and Energy: How Much Can You Reduce Your Electricity Bill?

Across the United States, millions of homeowners and businesses alike are looking at daylighting systems as a way to improve energy efficiency and fight back against rising energy costs.

Their interest is certainly understandable, as daylighting has been one of the most publicized and celebrated elements of energy efficiency. But how effective is it for businesses interested purely in reducing their monthly electricity bills?

Daylighting and Energy: How Much Can You Reduce Your Electricity BillIn simple terms, daylighting is the use of skylights and large windows to provide a home with natural light. The more natural light that can enter a home, the less the need for artificial lighting – an electricity-dependent solution – becomes.

Many of today’s energy-efficient homes and offices have achieved significant cost savings when compared to their older counterparts. How much of this, however, is due to effective design rather than just daylighting systems?

In 2005, the Energy Center of Wisconsin ran an experiment, aiming to find out the total savings possible by switching from inefficient artificial lighting to a source of natural light. Its results were, to say the least, quite startling.

Buildings designed using high-performance, energy-efficient design cost an average of $.07 less per square foot to light (15 cents per square foot vs. 22 cents per square foot) than standard rooms. Energy efficient buildings achieved a 32 percent saving – a significant amount – in the field of lighting alone.

When it comes to cooling, the results are similar. Energy efficient buildings cost just 14 cents per square foot to cool during summer, compared to 19 cents per square foot for standard rooms. The total energy demand was reduced by 24 percent – an impressive change with real financial effects for businesses and homeowners.

The benefits of switching to daylighting were clear from the experiment. The rooms lit using natural light were able to achieve the same degree of ambient light without using light fixtures at their full capacity. Even with the lights dimmed, the rooms lit using natural light were equally as bright as their artificially lit counterparts.

In fact, the Energy Center of Wisconsin reported that the savings in energy usage in lighting could have been even greater, had it not been for the overcast conditions in the area in which the experiment was conducted. The rooms were also very large, with certain areas unable to be lit fully using natural light on its own.

The Energy Center’s findings are impressive, and certainly a good indicator of the true value of daylighting. Residents and businesses in certain areas, such as Texas and California, with ample natural light, may be able to achieve even bigger savings in energy consumption due to greater amounts of natural sunlight.

Several other factors affect the savings possible using natural light. The design of a room has a significant impact, as does the efficiency of the daylighting system. With optimal skylight and window placement, greater savings can be achieved than with an inefficient system.

However, even at a base level, installing daylighting systems allows businesses and homeowners to achieve a significant reduction in energy costs. When paired with a greater approach to energy efficiency as a whole, daylighting can achieve massive savings that produce a real financial benefit for businesses and individuals.

“Image courtesy of Maria Toutoudaki/”

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