First Goal for Electrical Use: Cut Consumption
Efficient appliances; that participate in the government’s Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. program are easy to identify as those that use significantly less electricity than standard models. Some save water too.
Lighting and plug loads can help save energy every time you flick a switch. Compact fluorescent (CFLCompact fluorescent lamp. Fluorescent lightbulb in which the tube is folded or twisted into a spiral to concentrate the light output. CFLs are typically three to four times as efficient as incandescent lightbulbs, and last eight to ten times as long. CFLs combine the efficiency of fluorescent light with the convenience of an Edison or screw-in base, and new types have been developed that better mimic the light quality of incandescents. Not all CFLs can be dimmed, and frequent on-off cycling can shorten their life. Concerns have been raised over the mercury content of CFLs, and though they have been deemed safe, proper recycling and disposal is encouraged. ) bulbs can cut power use by 10%. It's also important to discover and eliminate phantom loads — electrical devices that use power even when they are "off." A whole-house electricity meter with an indoor display can help, because it gives real-time feedback on power usage habits.
Wind generators are becoming more residentially friendly. Most residential wind systems require a site with a minimum wind speed of 10 mph and enough land to permit the installation of a tower 80 to 120 feet tall. Manufacturers are beginning to develop small turbines designed for rooftop mounting, although the cost-effectiveness of such devices remains unproven.
Photovoltaic systems can produce clean electricity anywhere in the U.S. The equipment is simple, durable, and expensive.
ABOUT ELECTRICAL USE
Appliances and good habits can lower bills
On a BtuBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. basis, electricity is the most expensive form of residential energy in the U.S. Yet we use more of it — roughly 4.5 trillion Btu per year — than any other fuel except natural gas. An average household consumes 920 kilowatt-hours of power a month to feed a growing list of appliances and electronic devices and in the process spends just under $100 a month. While few households could do without electricity, most could find ways to reduce consumption.
Using less electricity has the obvious benefit of lowering monthly power bills. And because burning coal generates about half of the nation’s electrical supply, conservation also reduces the amount of carbon dioxide and other pollutants released into the atmosphere.
In residential construction, conservation techniques have nothing to do with the network of cables and switches we install. Those costs are essentially fixed no matter how much electricity is eventually used. Cutting consumption requires efficient appliances, a conservation-minded household, and common sense.
ABOUT ALTERNATIVE ENERGY
Will you pay more for environmental good?
In most cases, electricity generated on site with a photovoltaic or wind system will cost significantly more than grid power. However, some homeowners are willing to pay more for renewable energy because of its environmental advantages. Others feel more secure knowing that some of their energy is generated close to home. Amortized as part of a mortgage, photovoltaic or wind equipment can generate a positive cash flow, especially in states with generous renewable energy incentives or tax credits.
Photovoltaic (PV) modules produce electricity directly from sunlight. The silicon used to manufacture photovoltaic cells is plentiful, but is expensive to refine to a useful state. It costs between $30,000 and $60,000 to install a photovoltaic array large enough to meet the energy needs of a small house, so most residential PV systems meet only a fraction of the home's needs. Because of this cost, it takes high local electric rates, a low-interest loan, and generous state and federal incentives for a PV system to give you any financial benefit. But a PV system provides pollution-free electricity whenever the sun is shining. Of course, a PV array won't work at a shady site.
A wind generator requires a windy site
Large-scale wind farms are becoming increasing common, but wind generation is also a viable energy source on a small scale. Residential-sized systems are relatively expensive, but assuming there is enough wind at the site the cost per installed watt can be as low as half of that for a photovoltaic system. The clincher is that you need steady winds averaging 10 mph to make a wind turbine work, and plenty of room for a tall tower supported by guy wires.
On some sites, micro-hydro systems are an option
It doesn't take a major river to provide a reliable source of electricity. Micro-turbines work with water flow rates of 100 gallons per minute and vertical drops of between 50 feet and 100 feet. Unlike photovoltaic systems, turbines produce electricity reliably around the clock. To be sure, relatively few sites will have the right water resource, making this form of power generation a distant third to wind and sun. But it's an option worth exploring when conditions are promising.
MORE ABOUT ALTERNATIVE ENERGY
Grid-tied systems don't require batteries
Residential grid-tied renewable energy systems are made possible by net-metering legislation, which regulates how homeowners can feed power into the grid. Most grid-tied systems do not include battery backup, so if the grid goes down a house with a grid-tied solar or wind system is also without electricity. The main reason that grid-tied renewable energy systems can’t produce power during power outages is that gird-connected inverters require grid power to operate.
Electricity doesn’t flow directly from the photovoltaic array or the wind turbine into a house’s electrical system or into the grid. PV modules generate direct current (DC) power that is usually converted to alternating current (AC). An inverter between the photovoltaic array and the service and meter handles this task. A grid-tied wind turbine can produce either AC or DC power; in either case an inverter is required. AC turbines require an inverter to smooth out power delivery and make it compatible with the grid.
An off-grid system stores excess electricity in banks of batteries for use when the renewable energy system isn’t producing power. Deep-cycle batteries require regular maintenance; well-maintained batteries should last between 6 and 12 years. Regular battery replacement represents a substantial cost for off-grid homeowners.
PLAN FOR TECHNOLOGIES AHEAD
Make it easy to run cables when the need arises
It's impossible to anticipate exactly how technology will change in the future, or how each room in a house will be used over time. Running new electrical circuits or adding network cables is easier when conduit or accessible wiring chases are provided, and the best time to do that is when the rest of the electrical system is roughed in.
Time and materials are relatively modest when compared to the effort it would take when walls and ceilings have been finished. If conduits are buried in the walls of rooms that might be used as an office or home theater later, take a photo before walls are closed in and turn it over to homeowners or include it with the operator's manual for the house.
The same could be said for plug-in vehicles that automakers now have under development. Wiring the garage or an outside charging station as the rest of the electrical system is being installed will have benefits in the future.