US Energy Dept.'s New Video on Energy Efficient Designs and Retrofits for Commercial Buildings
April 18, 2014
Kyriaki (Sandy) Venetis in daylighting, electrochromic windows, energy costs, energy efficient commercial buildings, home energy audits, light bulbs/lamps, lighting control technologies, low e-rated or low thermal emissivity windows, thermochromic windows

The U.S. Energy Department just put out its newest informational video release – Energy Efficient Commercial Buildings – as part of its Energy 101Video Series.

While the video focuses a lot on taking a holistic approach to energy efficient design planning in new constructions, it also has a lot of ideas that can be retrofitted into both existing commercial and residential buildings with little expense.

These ideas are important, especially for commercial buildings, because the department says that, “About 20 percent of all the energy we use in the U.S. today goes to power commercial buildings, like the offices and schools we use everyday.”

The Energy Department said that depending on the level of energy efficient design implemented in a new construction or retrofitted into an existing structure, these “buildings can be up to 70 percent more efficient than conventional commercial buildings.”

One of the easiest approaches that can be taken to reduce energy costs in both new constructions and existing buildings, whether commercial or residential, is daylighting – the practice of using natural light to illuminate building spaces. To make the most use of the concept, there are some important aspects of daylighting to understand.

In the above video, the Energy Department explains that, “Daylighting combines a lot of things, everything from the type of window, window placement, and interior design to control how sunlight comes in. They all work to maximize benefits from natural sunlight.

“Windows that face south are best in the U.S. They let in the most sun during the winter months, but little direct sun during the summer, keeping the inside cooler. North-facing windows are also good for daylighting. They let in even natural light with little glare, with little summer heat.

“Windows that face east and west don’t work nearly as well for daylighting. They do provide lots of light in the morning and afternoon, but it often comes with lots of glare and excess heat during the summer months.”

The video also discusses how skylights as well as the right use to light ceiling and wall colors can further reflect and enhance natural interior lighting.

Several suggestions were also made in the video about how to deal with glare – especially if you have some of those east or west windows.

Among the Energy Department’s suggestions to minimize glare is to place either an awning or hood around a window, which will also “cut down on summer heat” and keep the interior space cooler and more comfortable. The department also suggests using either louvers or blinds inside to reduce glare and direct sunlight to reflective surfaces to maximize the amount of natural light inside.

If you’re willing to go a little more high-tech, there are a lot of new energy saving windows designed to block the outside temperature from coming in, including those with automatic tinting technology.

The Energy Department said that among the newest window options are low e-rated or low thermal emissivity windows, which are designed to reduce the level of thermal radiant energy (heat) from coming inside. Another option for creating a barrier against outside temperatures is installing triple-glazed windows.

Several years ago, as part of the Empire State Building’s massive energy efficiency retrofitting project, the building refurbished all of its approximately 6,500 thermopane (double-pane) windows, using its existing glass and sashes to create triple-glazed insulated panels to create a barrier against outside temperature conditions.

The Manhattan Chamber of Commerce said the Empire State Building’s new windows are “four times more thermally efficient compared to the older double-pane windows and are expected to reduce solar heat gain by more than 50 percent.”

Today, additional alternatives for protecting against outside temperatures as well as reducing glare are using electrochromic and thermochromic windows, which change their properties (either clouding or tinting) to control brightness and heat.

In combination with the use of windows to let in natural light as an energy saving measure, another light generating strategy is to use new energy efficient bulbs, such as compact florescents (CFLs), light emitting diodes (LEDs), or halogen bulbs.

In talking about interior lighting options, the Energy Department discusses lumens, which are a measure of brightness.

The Energy Department explained that, “In the past, we bought bulbs based on how much energy or how many watts they use. But, today’s energy saving light bulbs use up to 80 percent less power to give you the same amount of light.”

So the Energy Department advised that, “Instead of buying an inefficient 60 watt bulb, look for an efficient replacement that gives you about 800 lumens of light. If you are replacing a 100 watt bulb, look for an energy saving bulb that gives you about 1,600 lumens.”

You can find this information on the package of a bulb, as well as information about how much it will cost to operate the bulb for year, and about the bulb’s color.

Focusing on lighting, another way to reduce energy costs is to install sensor technology that detects whether a room is being occupied, and if a room is empty, the lights automatically shut off. Sensor technology includes occupancy sensors and light sensors.

All of these modifications can add up to hundreds of dollars in savings depending on the size of the home or building you are lighting.

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