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In a summer day, go outside and stay underneath the Sun for 5 minutes and you will feel the power the sun’ heat. The light the heat is solar energy. Most people know about active solar systems such as solar panels, solar power plants, but not the passive solar design.

You can use solar energy to do many things. Such as:

• Heat up your home using passive solar designs
• Generate your own electricity
• Even heat up the water in your swimming pool

The simplest and easiest way to use solar energy today is to line dry your clothes in the yard on on the balcony. You don’t need to invest thousands of dollars to start harvesting solar energy. Start today by lining your wet clothes up.

Solar power is the new old technology that people are using to help them save money. With the economy down and prices up, people are looking for new ways to save or even make money, which solar is a good option. With this, you can buy a pre build system that you piece together or you can make your own if you so inclined.

The savings on your electric bill can save you up to 100% of your bill if you get a large enough system. If you build a system that is bigger than you use, you can sell the power back to the electric company for a little bit of profit. This might vary state to state but most states are required to buy your power at market price.

The other plus of solar power is that you save the environment by using the natural power of the sun. If enough people use this way of power, we will all save a lot of money and cut down on carbon, and other emissions pumped into the air by power generation. So help yourself and the earth out and go green. Thank you and use solar power today.

Using passive solar design techniques to heat and cool your home can be both environmentally friendly and cost effective. Passive solar heating techniques include placing larger, insulated windows on south-facing walls and locating thermal mass, such as a concrete slab floor or a heat-absorbing wall, close to the windows. In many cases, your heating costs could be more than 50% lower than the cost of heating the same house that does not include passive solar design.

Passive solar design can also help reduce your cooling costs. Passive solar cooling techniques include carefully designed overhangs, windows with reflective coatings, and reflective coatings on exterior walls and the roof.

A passive solar house requires careful design and site orientation, which depend on the local climate. So, if you are considering passive solar design for new construction or a major remodeling, you should consult an architect familiar with passive solar techniques.

Solar Tips

• Keep all south-facing glass clean.
• Make sure that objects do not block the sunlight shining on concrete slab floors or heat-absorbing walls.

Source: EERE, US Department of Energy

Solar water heating systems usually cost more to purchase and install than conventional water heating systems. However, a solar water heater can usually save you money in the long run.

How much money you save depends on the following:

* The amount of hot water you use
* Your system’s performance
* Your geographic location and solar resource
* Available financing and incentives
* The cost of conventional fuels (natural gas, oil, and electricity)
* The cost of the fuel you use for your backup water heating system, if you have one.

On average, if you install a solar water heater, your water heating bills should drop 50%–80%. Also, because the sun is free, you’re protected from future fuel shortages and price hikes.

If you’re building a new home or refinancing, the economics are even more attractive. Including the price of a solar water heater in a new 30-year mortgage usually amounts to between $13 and $20 per month. The federal income tax deduction for mortgage interest attributable to the solar system reduces that by about $3–$5 per month. So if your fuel savings are more than $15 per month, the solar investment is profitable immediately. On a monthly basis, you’re saving more than you’re paying.

Source: EERE, U.S. Department of Energy

The National Fenestration Rating Council (NFRC) operates a voluntary program that tests, certifies, and labels windows, doors, and skylights based on their energy performance ratings. The NFRC label provides a reliable way to determine a window’s energy properties and to compare products.

The NFRC label can be found on all ENERGY STAR® qualified window, door, and skylight products, but ENERGY STAR bases its qualification only on U-factor and SHGC ratings.

Source: Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy

A window’s, door’s, or skylight’s ability to transmit sunlight into a home can be measured and rated according to the following energy performance characteristics:

* Visible transmittance (VT)

A fraction of the visible spectrum of sunlight (380 to 720 nanometers), weighted by the sensitivity of the human eye, that is transmitted through a window’s, door’s, or skylight’s glazing. A product with a higher VT transmits more visible light. VT is expressed as a number between 0 and 1. The VT you need for a window, door, or skylight should be determined by your home’s daylighting requirements and/or whether you need to reduce interior glare in a space.

* Light-to-solar gain (LSG)

The ratio between the SHGC and VT. It provides a gauge of the relative efficiency of different glass or glazing types in transmitting daylight while blocking heat gains. The higher the number, the more light transmitted without adding excessive amounts of heat. This energy performance rating isn’t always provided.

Source: Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy

You can use the energy performance ratings of windows, doors, and skylights to tell you their potential for gaining and losing heat, as well as transmitting sunlight into your home.
Heat Gain and Loss

Windows, doors, skylights can gain and lose heat in the following ways:

* Direct conduction through the glass or glazing, frame, and/or door

* The radiation of heat into a house (typically from the sun) and out of a house from room-temperature objects, such as people, furniture, and interior walls

* Air leakage through and around them.

These properties can be measured and rated according to the following energy performance characteristics:

* U-factor

The rate at which a window, door, or skylight conducts non-solar heat flow. It’s usually expressed in units of Btu/hr-ft2-ºF. For windows, skylights, and glass doors, a U-factor may refer to just the glass or glazing alone. But National Fenestration Rating Council U-factor ratings represent the entire window performance, including frame and spacer material. The lower the U-factor, the more energy-efficient the window, door, or skylight.

*Solar heat gain coefficient (SHGC)

A fraction of solar radiation admitted through a window, door, or skylight—either transmitted directly and/or absorbed, and subsequently released as heat inside a home. The lower the SHGC, the less solar heat it transmits and the greater its shading ability. A product with a high SHGC rating is more effective at collecting solar heat gain during the winter. A product with a low SHGC rating is more effective at reducing cooling loads during the summer by blocking heat gained from the sun. Therefore, what SHGC you need for a window, door, or skylight should be determined by such factors as your climate, orientation, and external shading. For more information about SHGC and windows, see passive solar window design.

*Air leakage

The rate of air infiltration around a window, door, or skylight in the presence of a specific pressure difference across it. It’s expressed in units of cubic feet per minute per square foot of frame area (cfm/ft2). A product with a low air leakage rating is tighter than one with a high air leakage rating.

Source: Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy

Heat-absorbing window glazing contains special tints that change the color of the glass. Tinted glass absorbs a large fraction of the incoming solar radiation through a window. This reduces the solar heat gain coefficient, visible transmittance, and glare.

Some heat, however, continues to pass through tinted windows by conduction and re-radiation. Therefore, the tint doesn’t lower a window’s U-factor. However, inner layers of clear glass or spectrally selective coatings can be applied on insulated glazing to help reduce these types of heat transfer.

Gray- and bronze-tinted windows—the most common—reduce the penetration of both light and heat into buildings in equal amounts (i.e., not spectrally selective). Blue- and green-tinted windows offer greater penetration of visible light and slightly reduced heat transfer compared with other colors of tinted glass. In hot climates, black-tinted glass should be avoided because it absorbs more light than heat.

Tinted, heat-absorbing glass reflects only a small percentage of light, so it does not have the mirror-like appearance of reflective glass.

Note: when windows transmit less than 70% of visible light, indoor plants can die or grow more slowly.

Source: Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy

Insulated window glazing refers to windows with two or more panes of glass. They are also called double-glazed, triple-glazed, and—sometimes more generally—storm windows.

To insulate the window, the glass panes are spaced apart and hermetically sealed to form a single-glazed unit with an air space between each pane of glass. The glass layers and the air spaces resist heat flow. As a result, insulated window glazing primarily lowers the U-factor, but it also lowers the solar heat gain coefficient.

Some window manufacturers use spacers—which separate two panes of glass—that conduct heat less readily than others. These spacers can further lower a window’s U-factor.

Other technologies window manufacturers use to improve the energy performance of insulated glazing include these:

* Gas fills
* Low-emissivity coatings.

Source: EERE, U.S. Department of Energy

Low-emissivity (Low-E) coatings on glazing or glass control heat transfer through windows with insulated glazing. Windows manufactured with Low-E coatings typically cost about 10%–15% more than regular windows, but they reduce energy loss by as much as 30%–50%.

A Low-E coating is a microscopically thin, virtually invisible, metal or metallic oxide layer deposited directly on the surface of one or more of the panes of glass. The Low-E coating reduces the infrared radiation from a warm pane of glass to a cooler pane, thereby lowering the U-factor of the window. Different types of Low-E coatings have been designed to allow for high solar gain, moderate solar gain, or low solar gain. A Low-E coating can also reduce a window’s visible transmittance unless you use one that’s spectrally selective.

To keep the sun’s heat out of the house (for hot climates, east and west-facing windows, and unshaded south-facing windows), the Low-E coating should be applied to the outside pane of glass. If the windows are designed to provide heat energy in the winter and keep heat inside the house (typical of cold climates), the Low-E coating should be applied to the inside pane of glass.

Window manufacturers apply Low-E coatings in either soft or hard coats. Soft Low-E coatings degrade when exposed to air and moisture, are easily damaged, and have a limited shelf life. Therefore, manufacturers carefully apply them in insulated multiple-pane windows. Hard Low-E coatings, on the other hand, are more durable and can be used in add-on (retrofit) applications. The energy performance of hard-coat, Low-E films is slightly poorer than that of soft-coat films.

Although Low-E coatings are usually applied during manufacturing, some are available for do-it-yourselfers. These films are inexpensive compared to total window replacements, last 10–15 years without peeling, save energy, reduce fabric fading, and increase comfort.

Source: EERE, U.S. Department of Energy