Daylighting
Using natural light to save energy in the home

Since the oil crunch of the 1970s, architects, engineers and homeowners have sought new ways to reduce America's reliance on traditional energy sources for heating and lighting homes. Certainly one of the most popular and promising answers to emerge has been solar energy. "Although nobody has officially counted, we project there are well over half a million passive solar houses in the United States," says Helen English, the Executive Director of the Passive Solar Industries Council.

With the solar heating movement, a less known but highly regarded design science has stepped to the fore--daylighting, the use of natural light to illuminate building interiors. Of course, this concept is as old as the window, but relatively recent advances in lighting research, window and glazing technology and lighting controls have opened up new horizons for daylighting.

THE HOUSE ADVANTAGE
We know that homeowners love the qualities of natural light--billions of dollars are spent each year on remodeling, often in an effort to achieve more light and spaciousness. But how far should homeowners go? Do they really need sophisticated daylighting systems? The answer seems to be this: You can enjoy and benefit from more natural light by taking advantage of selective daylighting principles and materials, but comprehensive daylighting systems don't make sense in most homes.

For one thing, the potential energy savings are not the same as for commercial and institutional buildings. Though houses do use plenty of electricity for lighting, high-wattage electric appliances and heating gobble up a healthy share of a home's power needs.

And there's the issue of occupancy. Unlike an office or library, many homes are relatively unoccupied during daylight hours, which shifts a larger percentage of electrical usage to the evenings.

Control is different too. At home, it's easy to flip off the lights when they're not needed. Sophisticated controls that automatically raise and lower indoor artificial light levels according to daylight are not necessary.

Providing natural light in houses is often fundamental to their design. As Russell Leslie and Kathryn Conway point out in The Lighting Pattern Book For Homes, published by Rensselaer's Lighting Research Center, "Homes often have generous amounts of daylight, and residential building codes require that most rooms have windows. Typical residential rooms are small enough so that daylight can reach deep into the room, particularly if windows are located high on the wall."

How to Cut Your Heating Bills: 7 Ways
Stay Warm and Save Energy This Winter

Looks like it's about time to break out my slippers and sweaters again. Many people believe that life in my neck of the woods--Southern California--is warm and sunny year-round. But even here, fall brings crisp days and chilly nights. Of course, conditions in colder climates are far worse, but we're not quite as well prepared for the cold. Many California houses are built with plentiful windows and wide-open floor plans, so dipping temperatures often result in cold, drafty rooms. So we crank-up our furnaces and, when we do, our heating bills go through the roof.

In the United States, we clearly have vast climate differences. But we all share a desire to stay warm and comfortable in the winter without spending a fortune on heat. With that in mind, let's look at a few ways you can achieve a more comfortable indoor environment while reducing energy costs.

1) Check your thermostat. If it isn't a programmable electronic one, replace it with one that is. A programmable thermostat can automatically adjust room temperature settings to energy-saving levels when you're sleeping or away from the house, eliminating wasteful energy usage. For more about electronic thermostats, see " Thermostats: Your Key to Comfort." See our report for more information on electronic thermostats.
Never set your thermostat higher than it needs to be for comfort. Over a 24-hour period, you can save about 3 percent of your energy costs for every degree you lower the thermostat's set temperature in the winter.

2) Seal up your house. If you haven't already done so, install weather stripping around windows and doors. Caulk any cracks or openings in the siding. And consider installing or repairing storm windows and storm doors. The idea is to prevent your home's expensively-heated air from escaping. See our report for more information on weather stripping.

3) Take advantage of the sun's warmth. Allow radiant energy from sunlight to augment your home's heating system simply by opening drapes and blinds on sunny days.

4) If you can do so relatively inexpensively, consider installing ceiling fans, particularly in rooms with high ceilings. Because warm air rises and can be trapped at the ceiling, a ceiling fan, when run in reverse direction during the winter, will circulate warm air back down to living areas. For more about ceiling fans, see the HomeTips "Ceiling Fans" report.

5) Be sure your home is adequately insulated. If it isn't, increase insulation, particularly in the attic. Not only is the attic usually the easiest place to insulate, but it's where you will see the greatest benefit in energy savings. For an in-depth discussion of insulation, see the HomeTips report on " Insulation."
6) Consider replacing your furnace if it's on its last legs. Forced-air heating systems are by far the most popular type of central heating, but most forced-air systems are sadly out-of-date. Some utilize only 50 percent of the fuel they burn. Newer models take advantage of up to 90 percent of their fuel. For more about these types of furnaces, see " High-Efficiency Furnaces: A Buying Guide."
7) Control the humidity levels in your home. For comfort in winter, your home's relative humidity levels should range from 30 to 50 percent. If they drop below this, the air becomes very dry and higher temperatures are required to feel warm. Conversely, if the air becomes too humid, windows drip with condensation. In most cases, the problem in winter is lack of humidity because using a heater dries out the air. To boost the humidity, you can buy a humidifier, which puts water vapor back into the air. Room or console humdifiers will handle individual rooms and small areas, but for the entire house you'll need a whole-house system that is installed as part of the heating system. For more about humdifiers, see " Humidifiers: A Buying Guide."
If after taking these measures you still haven't beat the winter chill, do what I do: put on some warm slippers and a sweater and cozy up to a warm fire.

How to Save Energy and Money on Lighting Your Home

If you're looking for ways to trim the fat from your electrical bills, consider some of these techniques, drawn from the experience of commercial daylighting experts: Turning off lights that aren't being used is a big one. Another is converting standard incandescent light bulbs to highly efficient compact fluorescents.

Compact fluorescents use from about one quarter to one third as much energy to produce the same amount of light as a standard incandescent bulb (a 20-watt compact fluorescent will give you about the same light as a 60-watt incandescent). Though most cost considerably more than conventional bulbs, they last up to thirteen times longer which, combined with the energy savings, makes them a long-term good buy.
If you want to get more natural light into areas that are away from windows, clerestories, atria or skylights, there are a few daylighting techniques that can help. First, try to bounce natural light off the ceiling. To do this, a window located close to the ceiling works well. Louvers or operable blinds can direct light, too.

You can also install a "light shelf" horizontally across a window to ricochet light off the ceiling and back into the room.. This shelf, normally located about 12 inches from the top of the window for a standard 8-foot ceiling (lower for a high ceiling), may be mounted inside, outside or in both locations. It's usually painted with high-reflectance, glossy paint. Actually, any light-toned surfaces, including walls, ceilings and floors, will reflect light. If you want more light in rooms and glare isn't a problem, look for wall paints that have high reflectance values (ask your paint dealer for them) and floor coverings that are light in color.

The bottom line is this: If you'd like to get more natural light into your home, consider some of the basic daylighting materials and techniques available. Thoughtful, controlled use of glazing combined with a few simple light-enhancing techniques can make nearly any home sparkle with natural light

Slash Your Electric Bills Now!
How to save energy and save money on your electric bills

Thanks to unusually harsh weather and poor public utility policies in some states, home electric bills have shot through the roof this year. Unfortunately, forecasters predict even higher electric prices when heavy cooling demands arrive with hot summer weather.
What can you do to take the strain off your electric meter?
Here are ten easy ways to slash your electric bills:

1) Turn off lights you're not using. This is a no-brainer and certainly one of the easiest measures of all, and yet it is a key step toward acting with a conservation mindset. Just flip a switch to stop wasting hundreds of watts of power every day.
2) Cut back on the lights you use. Indoors, use dimmers or decrease the wattage of bulbs. Opt for task lighting instead of general room lighting where possible. Outdoors, put motion sensors on light fixtures so bulbs only turn on when and where they are needed.
3) Adjust your thermostat. An air conditioner uses a tremendous amount of electricity when it runs. During the summer, you can realize major savings by raising the set temperature to 78 degrees F. or higher so the air conditioner will run less.
Conversely, turn the set temperature down during the winter (as a rule of thumb, every degree you lower a thermostat's set temperature in the winter will save 3% of energy costs over a 24-hour period.)
4) Use an electronic thermostat. If you don't already have a programmable electronic thermostat for your heating/cooling system, strongly consider replacing your existing thermostat with one. This device can be set to automatically adjust temperature settings to energy-saving levels when you're sleeping or away from the house.
5) Run the forced-air system's fan--not the air conditioner--to maintain a comfortable temperature during the summer. Simply flip the thermostat to "Fan Only" to recycle air throughout the house. (Of course, in a hot, humid climate, running the fan alone won't cool and dehumidify the house.) Also: Replace or clean the heating/cooling system's air filters to improve efficiency.
6) Maintain your refrigerator. Because it is one of the biggest energy-users in the home, a refrigerator should be operated at maximum efficiency. This means opening the door only briefly and adjusting the "Cold" control according to the manufacturer's directions. Vacuum refrigerator coils to remove excess dust.
Defrost if necessary (most refrigerators are frost-free). To reduce the amount of power the refrigerator's motor uses, consider plugging it into an electronic induction motor control such as the Power Planner, available in home improvement centers.

7) Use electrical appliances less. Only run an electric dryer with full loads or, even better, air-dry your clothes. Opt for cooking in the microwave instead of with an electric oven. And don't forget to turn off the coffee maker when the coffee is done. When buying new appliances, check the EnergyGuide labels to be sure they are energy efficient models.
8) Turn down the water heater temperature to a maximum of 120 degrees (to check the temperature, place a meat thermometer in a glass and run hot water into it for a couple of minutes). An electric water heater devours electricity! Obviously, if you have a gas water heater, this tactic will save you gas, not electricity.
9) Replace standard incandescent light bulbs with highly efficient compact fluorescent bulbs , which use from about one quarter to one third the energy to produce the same amount of light (a 20-watt compact fluorescent will give you about the same light as a 75-watt incandescent). Though most cost considerably more than conventional bulbs, they last up to thirteen times longer which, combined with the energy savings, makes them a long-term good buy.
10) Use natural light. Longer days and a higher summer sun angle afford you an opportunity to let Mother Nature help with the energy bills. The trick is to admit light without summer heat gain or glare (or winter heat loss). Fortunately, you can control heat gain and glare with window coverings and window films, available at home improvement centers. To increase the amount of natural light that floods a room, bounce it off the ceiling and walls with the aid of louvers or operable blinds (light-toned ceiling, walls, and floors work best). For more about using daylight, check out the HomeTips "Daylighting" report.
Though some of these methods may appear as though they will give you only minor relief from staggering electric bills, adopting several or all of them can result in significant overall savings. Many utilities charge higher rates for the portion of your electrical usage that exceeds baseline requirements. When you trim away the excess fat, you can dramatically lower your bills.

Window Placement for Optimal Use of Daylight

Of course, daylight originates at the sun. But more specifically, the daylight that enters a building may shine directly from the sun, bounce off of bodies of water, streets, buildings, or other surfaces, or come from the diffuse, day-lit sky.

Placing and sizing windows and figuring control measures, such as roof overhangs, requires a clear understanding of the sun's path. The sun's daily east-to-west arc changes throughout the year. At the summer solstice, June 21, the sun rises and sets farthest to the north, which means that it is higher during the day.
At the winter solstice, December 21, the sun's arc is at its southern-most position, with a much lower mid-day elevation. The sun's angle at any given time of the day depends on your latitude. The further north you live, the lower the winter sun will be in the southern sky.

Whether a window faces north, east, south or west makes a big difference in the type of light it receives.

If you want morning sunlight to spray across your breakfast table, your breakfast room window should face east.

Light from the south is bright and direct; solar houses are oriented to the south for maximum heat gain. South-facing windows are often located beneath eaves or roof overhangs that block the high, intense summer sun but allow the warmth of the lower winter sun.

Western sun can be intense and glaring. Controlling it is more difficult because, as the sun sets, its low angle dips beneath eaves and overhangs. Shades, blinds or glare-resistant glazing are generally required. It's also helpful if deciduous trees are planted on the west side of a house--their spring-and-summer leaves block unwanted heat, then when the leaves drop in the fall, the trees allow the sun's warmth and light.

North light, never direct from the sun, has cool, bluish hues because it comes from the sky. Because it's constant, north light is favored for artists' studios and the like.

Be sure any architect or builder you hire will take all of this into account when planning your house's window placement; ask for references and call previous clients.

Saving Energy in Commercial Structures Using Daylight

Because commercial and institutional buildings operate primarily during daylight hours and with clearly-defined schedules and because specific tasks are conducted in given areas, these kinds of buildings often lend themselves to comprehensive, systemized daylighting plans. And in these buildings, daylighting makes sense because of both energy savings and worker satisfaction.

When a building is flooded with well-controlled natural light, the amount of electricity needed for lighting may plummet. It's estimated that 25% to 40% of a commercial or institutional building's energy is needed for lighting, often at peak-demand prices; daylighting may save up to about 50% of that, depending upon how natural light is used.

That's significant, particularly in view of national energy picture. In the United States, electric lighting consumes about one fourth of all the energy generated. According to the Rocky Mountain Institute, a nonprofit research and educational organization that fosters efficient use of resources, this usage equals the energy produced by 170 large powerplants.

Workers prefer brighter, more naturally-lit environments, too. In fact, a number of studies support the idea that natural light has positive psychological effects on people. They suggest both that our brain perceives the color properties of natural light as "normal" and that we respond in a positive, physical way to its intensity. Russell Leslie, Associate Director of the Lighting Research Center at Rensselaer Polytechnic Institute in New York, points to evidence that shows high light levels can contribute to good health, comfort and productivity. He notes that depression caused by seasonal affective disorder (SAD), a sometimes debilitating condition that occurs at high latitudes where people are deprived of sufficient winter daylight, can be successfully treated with high light levels.