Although using sunlight as a source of illumination seems obvious, many modern buildings have all but blocked out and forgotten this free source of light. However, with the ever increasing concerns about energy consumption and as we better recognize the benefits of natural light for our health, more and more businesses are turning to daylight harvesting as a way to conserve energy and bring sunlight back into their buildings and workspaces.
What is Daylight Harvesting?
Any system or strategy that relies on daylight to offset electrical lighting needs is known as daylight harvesting or daylighting. Its main purposes are to conserve energy and to provide people with healthy, natural light even when they’re indoors. Daylight harvesting methods include everything from building orientation to advanced lighting control systems.
Why Should You Use it?
Lower Energy Costs
In most standard buildings, lighting accounts for around 38% of all consumed energy. Obviously, anything you can do to reduce this percentage would have a positive impact on your overhead costs. But you can’t simply turn down the lights and expect folks to work in dim conditions; you need some type of free, quality light to use in place or in conjunction with your electric setup. This is where daylight harvesting comes into play. In fact, depending on the depth of your daylight harvesting system, you can cut your lighting energy bill anywhere from 10% to 45%.
Also, because daylight harvesting has a lower cooling load than electric lighting, you can also see a reduction in your air conditioning costs.
Healthier Working Conditions
The demands of modern life mean most of us spend the majority of our days inside office buildings, schools, warehouses, and other indoor spaces. Still, while our lifestyles may have evolved away from working outdoors, our bodies still need sunlight in order to maximize mental function, keep a positive mood, maintain circadian rhythms, and to have good health.
While it may be surprising that mere sunlight can have such positive effects on people, the payoffs in regard to work productivity aren’t minor. For example, a 2003, California study found that workers who were exposed to daylight through a window performed 10% to 25% better on mental functioning tests as compared to those without a window view. In general, workers who have access to daylight are more alert, have better concentration, and have fewer absences due to illness. All-in-all, this means greater efficiency for your business and happier employees.
How to Start Implementing Daylight Harvesting?
Daylight harvesting isn’t quite as simple as pulling open the shades and allowing daylight to fill your building. Actually, if you’re not careful, you can end up creating glares (which can cause headaches and lower mental function) or letting in too much heat (which raises air conditioning costs). Thus, it’s best to plan your daylighting strategy carefully and to enlist the help of a lighting professional. Overall, the most effective systems use a combination of electric and natural light, as they ensure you always have adequate illumination and can switch between natural and artificial light when appropriate.
Types of Daylight Harvesting
If you’re constructing a new building, the first and foremost way to optimize it for daylight harvesting is to orient the building so the windows are north-facing. In the Northern Hemisphere, the sun only hits north-facing windows in the early morning and evenings. So, with a northerly orientation you can avoid the glares and heat of the sun during the brightest parts of the day.
Don’t worry if you discover your existing building has windows that face in an easterly or westerly direction. While it’s not ideal, you can control the amount of sunlight that comes indoors with things like overhangs, and shading devices. Plus, there are many other daylight harvesting tactics to employ.
Some of the most effective daylight harvesting strategies are:
Dimmers – Manual dimmers rely on people to regulate them, whereas automatic dimmers sense the amount of available sunlight and adjust the electric light accordingly.
Occupancy Sensors – These automatically turn out the lights when the room is empty.
Optical Sensors – These are photocells that read ambient light levels and use as much daylight as possible while still maintaining a set standard of illumination.
Timers – Lets you control what lights are active during certain times of the day and in specific areas of the building.
Skylights and Other Top Lighting – Skylights are especially useful when windows have poor orientation and in rooms where there are no windows.
Energy Efficient Windows – High-quality windows allow sunlight to come inside but are sufficiently insulated to block heat transfer.
Shades, shutters, louvers, and other diffusers – Place these on windows and skylights to adjust the amount of sunlight.
In most cases, the more you can automate the lighting system, the more energy you will save. For this reason, the most advanced systems are all connected to a control panel, which uses software to let you fine tune the lighting setup in every room or zone of the building. Still, it’s always a good idea to have manual overrides on dimmers and the like, so people can adjust the light to their personal preferences.
Getting the Most out of Daylighting
The most important thing to remember about daylighting is that its success relies on strategic design. A lighting professional, such as Premier Lighting, can help you determine what combination of lighting tools will work best for your facility. Lighting upgrades usually have a ROI of two to five years, and with the added government incentives for “green” buildings, you can recoup your investment costs even sooner. Not to mention, you’ll immediately reduce your business’ energy consumption and enjoy the advantage of happier, more efficient workers.