Electrical

Saving electricity saves money, decreases air pollution, and allows for more reliable energy delivery.

Because electricity generation is a leading source of the carbon dioxide emissions that cause climate change, using less electricity saves dollars and has a global impact. While many design features impact a building's electricity use, fixtures and equipment that use electricity directly are obvious targets for energy–saving measures.

1 Lighting levels
2 Energy-efficient fixtures
3 Controls & sensors
3 Energy Star
3 Energy management system

Goal: Save energy in lighting

When you design a lighting system, see if you can use windows or skylights to provide day lighting first (see Chapter 7), and then select efficient fixtures. New technologies can switch lights off or dim them when not in use to save more energy.

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Design lighting levels for actual use, and use task lighting to reduce general lighting levels

What is this?

Different lighting levels are needed for different activities — for example, reading requires more light than walking down a hallway. A variety of lights are needed to match the variety of uses expected in every space.

Why do it?

Many buildings are vastly over–lit, which not only wastes money, but also reduces people's ability to use contrasts in lighting to identify important variations in space, making places bland and occasionally hard to use.

How to do this?

Recent standards from the Illuminating Engineer Society of North America have reduced recommended general ("ambient") light levels, recognizing that it is more important to light actual work areas ("tasks") than whole rooms. The ambient light level should be enough for general comfort, and need not be more than that. With computer screens, task areas may be effectively self–lighting.

Who does this?

Architects, electrical engineers, lighting designers.


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Use energy–efficient lamps and lighting fixtures

What is this?

Use fluorescent lighting everywhere. Choosing the bulbs with the highest lumens per watt (at least 70 lumens/watt) and the highest color rendering index (CRI 80 or above) will give the greatest efficiencies and the best color. Replace incandescent bulbs, even in homes, with high–CRI compact fluorescent bulbs. For commercial fixtures, look for a high coefficient of utilization (CU 90 or above), which indicates how well the fixture distributes light.

Why do it?

Choosing fixtures that use all the light a bulb produces just makes sense — why absorb the light or point it where it's not needed? Fluorescent lights have made many recent improvements: new fluorescent lights don't flicker, have the same color light as incandescents, and produce 80% more lumens per watt. They also last up to eight times as long as incandescents, saving maintenance and replacement costs.

How to do this?

Use fluorescent lighting everywhere. Choosing the bulbs with the lowest lumens per watt and the highest color rendering index (CRI) will give the greatest efficiencies and the best color. Replace incandescent bulbs, even in homes, with high–CRI compact fluorescent bulbs. For commercial fixtures, look for a high coefficient of utilization (CU), which indicates how well the fixture distributes light.

Who does this?

Building owners, architects, electrical engineers, lighting designers, tenants.


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Use lighting controls that save energy such as occupancy sensors

What is this?

Lighting controls are the switches that control lights, whether by manual operation or digital signals from light, motion and infrared sensors.

Why do it?

There's no point in providing electric light if no one's using it or free daylight is already arriving in the same place. Investments in lighting controls can pay for themselves rapidly by reducing energy waste. Some controls are already required by the State energy code (often referred to as "Title 24").

How to do this?

Use occupancy sensors to switch off lights in rooms that get occasional use such as garages, bathrooms, and conference rooms. Use light–level sensors to dim switch off lights in areas that have access to daylight such as open office areas, classrooms and workspaces.

Who does this?

Architects, electrical engineers, lighting designers.


Goal: Save energy in equipment use

A lot of electricity used in buildings goes to appliances and equipment, and large cost savings are almost always possible by improving efficiency (see also Chapter 10). Efficiencies are available both when buying or replacing individual appliances, such as refrigerators, and in larger integrated systems that link many devices together.

Fluorescent bulb Image

Using compact fluorescent bulbs is an easy way to save money and electricity.


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Use ENERGY STAR® appliances

What is this?

Energy Star is a U.S. Department of Energy program that sets standards for energy efficiency in a variety of appliances and other products and systems — both for household and business uses. Criteria to be an ENERGY STAR product vary by product type, and usually require products to exceed minimum efficiency standards by at least 10–25% and use low–power "sleep" modes.

Why do it?

The average household spends $1,400 on energy costs per year, and savings through appliances can approach $100 of this or more. For example, refrigerators can use 25% of all household electricity and using an ENERGY STAR refrigerator can save 40–60% of that; ENERGY STAR washing machines use 50% less energy than older models.

How to do this?

Look for ENERGY STAR labels and electricity usage information on appliances and purchase accordingly.

Who does this?

Building owners, tenants.


Products that meet ENERGY STAR standards are easy to identify by checking for this logo.

Energy Star Logo

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Use a building energy management system

What is this?

A building energy management system (BEMS) is a computer that controls all major building equipment such as heating, ventilation, and air conditioning units, elevators, lighting, etc.

Why do it?

BEMS's save on average 10% of total building energy use. They also collect information on building energy use, allowing for better maintenance, replacement, and adjustment over time.

How to do this?

Study your building's needs and clearly and accurately specify a BEMS that has appropriate computing power and control strategies. Make sure the system is fully inspected and tested during installation and after occupancy (called "commissioning") to ensure that it works as intended.

Who does this?

Building owners with large (over 100,000 square feet) or energy–intensive projects, architects, specification writers, electrical and mechanical engineers.


More Information

Illuminating Engineers Society of North America
Energy Design Resources design briefs,"Energy Management Systems"
ENERGY STAR Program
Pacific Energy Center
Rebates & Incentives