Who Saved Watt?!

President Barack Obama declassified satellite imagery that graphically show the effect of global warming.  The imagery was previously kept classified by the Bush administration.

Read more:

http://www.guardian.co.uk/environment/2009/jul/26/climate-change-obama-administration

View the images:

http://gfl.usgs.gov/Publications.shtml

This interesting article in The Economist talks about two companies (one in Norway, the other in the Netherlands) who have created processes that harden softwoods so that they don’t rot and aren’t susceptible to bugs.

I know bamboo is a sustainable wood product that has been used for hardwood floors. It’s even been used to make fabric and cloth.  But treating softwoods to take on the properties of hardwoods is a new and potentially valuable technique. Softwood trees account for the vast majority (80%) of the world’s timber.  Making that timber into durable building products goes a long way towards sustainable development.

Solar heat absorbed through windows and roofs can increase your air conditioner use. Incorporating shading concepts into your landscape design can help reduce this solar heat gain, reducing your cooling costs.

Shading and evapotranspiration (the process by which a plant actively moves and releases water vapor) from trees can reduce surrounding air temperatures as much as 9° F (5°C). Because cool air settles near the ground, air temperatures directly under trees can be as much as 25°F (14°C) cooler than air temperatures above nearby blacktop.

Using shade effectively requires you to know the size, shape, and location of the moving shadow that your shading device casts. Also, homes in cool regions may never overheat and may not require shading. Therefore, you need to know what landscape shading strategies will work best in your regional climate and your microclimate.

Trees can be selected with appropriate sizes, densities, and shapes for almost any shading application. To block solar heat in the summer but let much of it in during the winter, use deciduous trees. To provide continuous shade or to block heavy winds, use dense evergreen trees or shrubs.

Deciduous trees with high, spreading crowns (i.e., leaves and branches) can be planted to the south of your home to provide maximum summertime roof shading. Trees with crowns lower to the ground are more appropriate to the west, where shade is needed from lower afternoon sun angles. Trees should not be planted on the southern sides of solar-heated homes in cold climates because the branches of these deciduous trees will block some winter sun.

Although a slow-growing tree may require many years of growth before it shades your roof, it will generally live longer than a fast-growing tree. Also, because slow-growing trees often have deeper roots and stronger branches, they are less prone to breakage by windstorms or heavy snow loads. Slow-growing trees can also be more drought resistant than fast-growing trees.

A 6-foot to 8-foot (1.8-meter to 2.4-meter) deciduous tree planted near your home will begin shading windows the first year. Depending on the species and the home, the tree will shade the roof in 5–10 years. If you have an air conditioner, shading the unit can increase its efficiency by as much as 10%.

Trees, shrubs, and groundcover plants can also shade the ground and pavement around the home. This reduces heat radiation and cools the air before it reaches your home’s walls and windows. Use a large bush or row of shrubs to shade a patio or driveway. Plant a hedge to shade a sidewalk. Build a trellis for climbing vines to shade a patio area.

Vines can also shade walls during their first growing season. A lattice or trellis with climbing vines, or a planter box with trailing vines, shades the home’s perimeter while admitting cooling breezes to the shaded area.

Shrubs planted close to the house will fill in rapidly and begin shading walls and windows within a few years. However, avoid allowing dense foliage to grow immediately next to a home where wetness or continual humidity are problems. Well-landscaped homes in wet areas allow winds to flow around the home, keeping the home and its surrounding soil reasonably dry.

Reprinted from http://www.energysavers.gov/your_home/landscaping/index.cfm/mytopic=11940
EERE copyright: “Materials on the EERE Web site are in the public domain. EERE requests that it be acknowledged as the source in any subsequent use of its information.”
See http://www1.eere.energy.gov/webpolicies/ for more information on copyright

Did you know that 24% of our trash in the landfill is composed of grass, leaves, and organic kitchen scraps?  That’s perfect compost!

This interesting article gives 5 great reasons to grow a Victory Garden.

It makes sense, too.  Growing your own stuff saves money, it’s healthier, and its good for the environment.

Want to drive one month for free?  Below are 5 simple steps towards better fuel efficiency that will help pay for your extra month of driving.  When the numbers are applied to the nation as a whole, the amount of conservation achieved is mind boggling.  A few thrifty, conservative tips will save you and our entire country save a whole lot of money.

Drive Like Gandhi

Ok, maybe Gandhi didn’t drive much, but can you imagine him driving aggressively?  Aggressive driving (speeding, rapid acceleration and braking) wastes gas. According to FuelEconomy.gov, aggressive driving can lower your gas mileage by 33 percent at highway speeds and by 5 percent around town.

That’s 5% to 33% wasted gas because cutting off that idiot on the highway during traffic and getting one car length ahead makes you feel better.  What does that cost you?

At $2/gal,  that’s $0.10 to $0.66 per gallon!  Just a few summers ago, gas was over $4/gal.  Aggressive driving costs up to $1.32 per gallon!  That’s over 5 bucks for a gallon of gas!

Sensible driving is also safer for you and others, so you may save more than gas money.

Buy a manual transmission

I, personally, think a stick shift is more fun to drive, but it’s also significantly more efficient than a manual transmission.

Consumer Reports shows 10% better gas mileage on many common manual tranmission cars.  The same study also shows better 0-60 acceleration.

Why is that?  Because you, the smart driver, can shift earlier or later, as needed.   When I drive a stick, I conscious shift into higher gears earlier than an automatic transmission would.  I watch the tachometer sink to lower RPM levels, which means the engine is using less gas.  Likewise, you can ride out a lower gear longer when accelerating, giving you higher RPMs, which gives you more power to accelerate more quickly.

More than that, sticks just look cooler.  True story, my brother once bought a (used) Corvette when he was younger.  He wanted to look cool… except I made fun of him for buying a corvette with an automatic transmission.  I often look into the windows of Mustangs and other sporty cars.  Only manual trannies make the grade.

I’m pretty sure Gandhi would have loved a stick.

Observe the Speed Limit!

Gandhi wouldn’t speed either, would he?  Each vehicle has its own optimal cruising speed, but all vehicles experience rapid decreases in efficiency after 60mph.

The rule of thumb is  about $0.24 per 5mph over 60.  Want to cruise at 70mph?  You might make good time on your trip, but you’re paying half a buck more per gallon for it.

Lose the weight!

Gandhi wasn’t a big guy and he didn’t have much stuff to haul around.  Each 100lbs. of weight costs you 1-2% fuel efficiency.  This impacts smaller cars worse than larger ones.

Got some golf clubs in the back you’re hauling around?  Get ‘em out!  Unless you are playing that day, store them in the garage.  Keeping them in your car is costing you money.

Keep your car in shape

The GOP may have teased Obama’s energy plan by giving out tire gauges labelled “Obama’s Energy Plan” during the campaign, but the President was right.  Keeping your tires properly inflated will improve efficiency up to 3% or 0.3% for every 1 PSI for all four tires.

Keeping your car well-tuned and in good shape yields another 4%.  Regular oil changes and using the correct type of oil recommended by the manufacturer yields another 1-2%. (See stats).

Gandhi was a vegetarian, refrained from drinking alcohol, and refrained from promiscuity. The man would have taken good care of his car.

TOTAL SAVINGS?

Gandhi believed in collective action. An individual is powerless, but a nation’s collective will is immensely strong.

What do all these fuel efficiency savings add up to when applied to the entire U.S.?  Hundreds of millions of barrles of oil and billions of dollars.

12,000 miles per year at an average of 25mpg is 480 gallons of gas or about $1,200. All of the tips above could reasonably achieve 25% gains in efficiency.  Reducing your bill by 25% means you’ll only spend $900.  $300 savings!

What, you aren’t impressed by $300 annual savings?  Let’s look at the big picture…

The Bureau of Transportation Statistics says there are over 250 million cars in the U.S. and the Federal Highway Administration says American drivers laid down 249.5 billion miles of rubber just in April 2009! That’s around 3 trillion miles driven annually.

Now, I think that’s a lot of miles, and what if we all achieved a mere 10% better fuel efficiency?  We, as a nation, would save over 300 billion miles worth of gas.  That’s a full month of driving everywhere in America.

How much oil is that?  Aren’t we all trying to reduce our dependence on foreign oil?

According to the Energy Information Administration, a single barrel of oil makes roughly 20 gallons of gas. The BTS says the average car in America gets about 22mpg.  So, one barrel of oil will power a single car for about 440 miles. Saving 300 billion miles of driving will reduce our need for over 680 million barrels of oil! (300b miles / 440 miles per barrel = 681m barrels). At $50 a barrel, that’s over $34 billion saved.

The EIA says we consume roughly 20m barrels of oil daily in the U.S., with nearly half of that (9m barrels) being used for gasoline.  Saving 680m barrels of oil by simply increasing fuel efficiency by 10% means we’d save 34 days worth of oil.

There’s your free month of driving.  See you on the highway, but first check your tires.

Solar access is the availability of (or access to) unobstructed, direct sunlight. Your access to sunlight becomes important if you use solar energy for space heating (and cooling), water heating, electricity, and/or daylighting.

Solar access issues emerged in the United States initially as a means by which landowners could attempt to protect their “access,” or use, of solar radiation from present or future impairment. For example, a laundry with solar water heater collectors on its roof could legally alter any nearby structural development that could cast a shadow on the collectors and negatively affect system performance.

Early efforts to protect solar access took the view that every landowner’s right to natural sunlight deserved protection. It was later realized that broad solar access substantially benefited the entire community in many ways. Energy/cost savings, comfort, construction cost savings, enhanced market value, future solar energy utilization potential, and aesthetics were all improved.

Several communities in the United States have developed solar access planning guidelines and/or ordinances. Data gathering, policy determination and development, and integrating new and/or existing statutes with solar access are necessary steps in the process. Zoning is a common mechanism used to protect solar access.

Solar Landscaping

It’s important to encourage compatibility between landscaping, shading, and solar access goals. Studies by the Lawrence Berkeley National Laboratory estimate a 25%–50% reduction in annual cooling energy consumption through well-designed landscape design. Additional benefits of energy-efficient landscaping include aesthetics, environmental quality, noise buffering, privacy, and spatial definition.

Solar Building Design

With optimum orientation, it is much easier to design buildings to incorporate solar features, such as passive space heating and cooling and daylighting. Many solar design strategies are highly cost-effective when incorporated into the initial building design. This typically reduces costs for initial capital investment in the building heating and cooling equipment, and ongoing operating costs.

The City of San Jose, California, for example, precisely describes what constitutes a solar access dwelling unit. There, the amount of shade on the dwelling unit defines its level of solar access. According to the City of San Jose, shading from a structure and/or vegetation must not exceed specific amounts.

Solar Energy Systems

Unobstructed access to the sun is necessary for the optimum performance of active and passive solar energy systems. There is generally no guarantee a solar system will always have unobstructed access to the sun. Every day, decisions about the built environment and landscape effect the future shading of existing or potential sites.

Solar access protection is clearly advantageous for the following systems in the associated locations:

• Rooftop: solar water heater and space heating collectors and photovoltaic arrays
• Walls: passive solar systems such as Trombe walls, attached solar greenhouses, and direct gain systems
• Lot (south-facing): ground-mounted or detached active collector systems.

Data Gathering

A number of communities throughout the country have created solar access policies and regulations according to unique local situations. If a community wishes to develop a plan for protecting solar access, they must take a number of steps to achieve its goal.

If there are no local solar access laws, private citizens requiring access to sunlight may have to bear the cost of private solar access agreements through such devices as easements or restrictive covenants.

Legislative Barriers

Zoning ordinances and building codes can create problems for solar access. Most pertain to the following:

• Height
• Setback from the property line
• Exterior design restrictions
• Yard projection
• Lot orientation
• Lot coverage requirements.

The most important solar access regulation for subdivision development is a predominantly east-west street orientation. This promotes optimal building orientation for solar access.

Related Information

• Building Codes, Covenants, and Regulations for Solar Energy Systems
• Solar Radiation Basics

Learn More

Financing & Incentives

• Find Federal Tax Credits for Energy EfficiencyENERGY STAR®

State & Local Resources

• Status of State Energy Codes DOE Building Energy Codes Program
• State ChaptersSolar Energy Industries Association

Related Links

• American Solar Energy Society

Reading List

• Starrs, T.; Nelson, L.; Zalcman, L. (1999). Bringing Solar Energy to the Planned Community (PDF 1 MB). U.S. Department of Energy. Describes neighborhood covenants as they relate to rooftop photovoltaic and solar water heating installations. Includes information on obtaining approval for your design, your legal options, and removing barriers to solar installations.
• Zalcman, F. et al. (2000). “Overcoming Private Land Use Restrictions on Solar Energy Systems,” Solar 2000: Proceedings of the Annual American Solar Energy Society Conference, Madison, Wisconsin, June 16-21, 2000; pp. 169-178.
• Huddy, P. (1999). “The Power of Community as a Basis for Advancing Solar Energy Use—The Tucson Experience.” Solar 99, Proceedings of the American Solar Energy Society Annual Conference and 24th National Passive Solar Conference. Portland, ME, June 12-16, 1999. 766 pp.
• Ravetto, A. et al. (1997). “Site Planning and Solar Access,” Proceedings of the 22nd National Passive Solar Conference. Washington, DC, April 25-30, 1997. 381 pp.

Reprinted from http://www.energysavers.gov/renewable_energy/solar/index.cfm/mytopic=50013
EERE copyright: “Materials on the EERE Web site are in the public domain. EERE requests that it be acknowledged as the source in any subsequent use of its information.”
See http://www1.eere.energy.gov/webpolicies/ for more information on copyright

Rock Port, MO’s new wind turbines at Loess Hills Wind Farm will soon be generating more power than the local residents consume.  Four 1.25 megawatt turbines will generate 5 megawatts of power daily or 16 gigawatt hours (16 million kilowatt hours) annually.  The local residents historically uses 13 gigawatt hours.

At an average cost of $0.11 per kilowatt hour, that’s over $1.7 million in energy cost savings.  Excess energy is being bought by Missouri Joint Municipal Utilities.

This should be the new standard for sustainable living and development.

See these links for more information.

The Economist (one of my favorite magazines) is running an article about AeroGrow, a company producing a simple household appliance that lets you almost effortlessly grown fresh produce in your own kitchen.  The technique is not new.  Using “aeroponics” to grow plants quickly without soil has been practiced for a long time by those growing their own marijuana.  But this company is the first to mass market an appliance that’s inexpensive, looks good, and can produce quality stuff for you and your family.

The article talks a lot about the business model and the founder of the company, but you would expect this from a magazine called “The Economist.”

Fascinating read.  You can read the full here.

Solar radiation is a general term for the electromagnetic radiation emitted by the sun. We can capture and convert solar radiation into useful forms of energy, such as heat and electricity, using a variety of technologies. The technical feasibility and economical operation of these technologies at a specific location depends on the available solar radiation or solar resource.

American Solar Map

Basic Principles

Every location on Earth receives sunlight at least part of the year. The amount of solar radiation that reaches any one “spot” on the Earth’s surface varies according to these factors:

• Geographic location
• Time of day
• Season
• Local landscape
• Local weather.

Because the Earth is round, the sun strikes the surface at different angles ranging from 0º (just above the horizon) to 90º (directly overhead). When the sun’s rays are vertical, the Earth’s surface gets all the energy possible. The more slanted the sun’s rays are, the longer they travel through the atmosphere, becoming more scattered and diffuse. Because the Earth is round, the frigid polar regions never get a high sun, and because of the tilted axis of rotation, these areas receive no sun at all during part of the year.

The Earth revolves around the sun in an elliptical orbit and is closer to the sun during part of the year. When the sun is nearer the Earth, the Earth’s surface receives a little more solar energy. The Earth is nearer the sun when it’s summer in the southern hemisphere and winter in the northern hemisphere. However the presence of vast oceans moderates the hotter summers and colder winters one would expect to see in the southern hemisphere as a result of this difference.

The 23.5º tilt in the Earth’s axis of rotation is a more significant factor in determining the amount of sunlight striking the Earth at a particular location. Tilting results in longer days in the northern hemisphere from the spring (vernal) equinox to the fall (autumnal) equinox and longer days in the southern hemisphere during the other six months. Days and nights are both exactly 12 hours long on the equinoxes, which occur each year on or around March 23 and September 22.

Countries like the United States, which lie in the middle latitudes, receive more solar energy in the summer not only because days are longer, but also because the sun is nearly overhead. The sun’s rays are far more slanted during the shorter days of the winter months. Cities like Denver, Colorado, (near 40º latitude) receive nearly three times more solar energy in June than they do in December.

The rotation of the Earth is responsible for hourly variations in sunlight. In the early morning and late afternoon, the sun is low in the sky. Its rays travel further through the atmosphere than at noon when the sun is at its highest point. On a clear day, the greatest amount of solar energy reaches a solar collector around solar noon.

Diffuse and Direct Solar Radiation

As sunlight passes through the atmosphere, some of it is absorbed, scattered, and reflected by the following:

• Air molecules
• Water vapor
• Clouds
• Dust
• Pollutants
• Forest fires
• Volcanoes.

This is called diffuse solar radiation. The solar radiation that reaches the Earth’s surface without being diffused is called direct beam solar radiation. The sum of the diffuse and direct solar radiation is called global solar radiation. Atmospheric conditions can reduce direct beam radiation by 10% on clear, dry days and by 100% during thick, cloudy days.

Measurement

Scientists measure the amount of sunlight falling on specific locations at different times of the year. They then estimate the amount of sunlight falling on regions at the same latitude with similar climates. Measurements of solar energy are typically expressed as total radiation on a horizontal surface, or as total radiation on a surface tracking the sun.

Radiation data for solar electric (photovoltaic) systems are often represented as kilowatt-hours per square meter (kWh/m²). Direct estimates of solar energy may also be expressed as watts per square meter (W/m²).

Radiation data for solar water heating and space heating systems are usually represented in British thermal units per square foot (Btu/ft²).

Learn More

Department of Energy Resources

• Solar Radiation Resource Information
  Renewable Resource Data Center

Reprinted from http://www.eere.energy.gov/consumer/renewable_energy/solar/index.cfm/mytopic=50012
EERE copyright: “Materials on the EERE Web site are in the public domain. EERE requests that it be acknowledged as the source in any subsequent use of its information.”
See http://www1.eere.energy.gov/webpolicies/ for more information on copyright

You can easily conduct a home energy audit yourself. With a simple but diligent walk-through, you can spot many problems in any type of house. When auditing your home, keep a checklist of areas you have inspected and problems you found. This list will help you prioritize your energy efficiency upgrades.

Locating Air Leaks

First, make a list of obvious air leaks (drafts). The potential energy savings from reducing drafts in a home may range from 5% to 30% per year, and the home is generally much more comfortable afterward. Check for indoor air leaks, such as gaps along the baseboard or edge of the flooring and at junctures of the walls and ceiling. Check to see if air can flow through these places:

• Electrical outlets
• Switch plates
• Window frames
• Baseboards
• Weather stripping around doors
• Fireplace dampers
• Attic hatches
• Wall- or window-mounted air conditioners.

Also look for gaps around pipes and wires, electrical outlets, foundation seals, and mail slots. Check to see if the caulking and weather stripping are applied properly, leaving no gaps or cracks, and are in good condition.

Inspect windows and doors for air leaks. See if you can rattle them, since movement means possible air leaks. If you can see daylight around a door or window frame, then the door or window leaks. You can usually seal these leaks by caulking or weather stripping them. Check the storm windows to see if they fit and are not broken. You may also wish to consider replacing your old windows and doors with newer, high-performance ones. If new factory-made doors or windows are too costly, you can install low-cost plastic sheets over the windows.

If you are having difficulty locating leaks, you may want to conduct a basic building pressurization test:

1. First, close all exterior doors, windows, and fireplace flues.
2. Turn off all combustion appliances such as gas burning furnaces and water heaters.
3. Then turn on all exhaust fans (generally located in the kitchen and bathrooms) or use a large window fan to suck the air out of the rooms.

This test increases infiltration through cracks and leaks, making them easier to detect. You can use incense sticks or your damp hand to locate these leaks. If you use incense sticks, moving air will cause the smoke to waver, and if you use your damp hand, any drafts will feel cool to your hand.

On the outside of your house, inspect all areas where two different building materials meet, including:

• All exterior corners
• Where siding and chimneys meet
• Areas where the foundation and the bottom of exterior brick or siding meet.

You should plug and caulk holes or penetrations for faucets, pipes, electric outlets, and wiring. Look for cracks and holes in the mortar, foundation, and siding, and seal them with the appropriate material. Check the exterior caulking around doors and windows, and see whether exterior storm doors and primary doors seal tightly.

When sealing any home, you must always be aware of the danger of indoor air pollution and combustion appliance “backdrafts.” Backdrafting is when the various combustion appliances and exhaust fans in the home compete for air. An exhaust fan may pull the combustion gases back into the living space. This can obviously create a very dangerous and unhealthy situation in the home.

In homes where a fuel is burned (i.e., natural gas, fuel oil, propane, or wood) for heating, be certain the appliance has an adequate air supply. Generally, one square inch of vent opening is required for each 1,000 Btu of appliance input heat. When in doubt, contact your local utility company, energy professional, or ventilation contractor.

Insulation

Heat loss through the ceiling and walls in your home could be very large if the insulation levels are less than the recommended minimum. When your house was built, the builder likely installed the amount of insulation recommended at that time. Given today’s energy prices (and future prices that will probably be higher), the level of insulation might be inadequate, especially if you have an older home.

If the attic hatch is located above a conditioned space, check to see if it is at least as heavily insulated as the attic, is weather stripped, and closes tightly. In the attic, determine whether openings for items such as pipes, ductwork, and chimneys are sealed. Seal any gaps with an expanding foam caulk or some other permanent sealant.

While you are inspecting the attic, check to see if there is a vapor barrier under the attic insulation. The vapor barrier might be tarpaper, Kraft paper attached to fiberglass batts, or a plastic sheet. If there does not appear to be a vapor barrier, you might consider painting the interior ceilings with vapor barrier paint. This reduces the amount of water vapor that can pass through the ceiling. Large amounts of moisture can reduce the effectiveness of insulation and promote structural damage.

Make sure that the attic vents are not blocked by insulation. You also should seal any electrical boxes in the ceiling with flexible caulk (from the living room side or attic side) and cover the entire attic floor with at least the current recommended amount of insulation.

Checking a wall’s insulation level is more difficult. Select an exterior wall and turn off the circuit breaker or unscrew the fuse for any outlets in the wall. Be sure to test the outlets to make certain that they are not “hot.” Check the outlet by plugging in a functioning lamp or portable radio. Once you are sure your outlets are not getting any electricity, remove the cover plate from one of the outlets and gently probe into the wall with a thin, long stick or screwdriver. If you encounter a slight resistance, you have some insulation there. You could also make a small hole in a closet, behind a couch, or in some other unobtrusive place to see what, if anything, the wall cavity is filled with. Ideally, the wall cavity should be totally filled with some form of insulation material. Unfortunately, this method cannot tell you if the entire wall is insulated, or if the insulation has settled. Only a thermographic inspection can do this.

If your basement is unheated, determine whether there is insulation under the living area flooring. In most areas of the country, an R-value of 25 is the recommended minimum level of insulation. The insulation at the top of the foundation wall and first floor perimeter should have an R-value of 19 or greater. If the basement is heated, the foundation walls should be insulated to at least R-19. Your water heater, hot water pipes, and furnace ducts should all be insulated.
For more information, see our insulation section.

Heating/Cooling Equipment

Inspect heating and cooling equipment annually, or as recommended by the manufacturer. If you have a forced-air furnace, check your filters and replace them as needed. Generally, you should change them about once every month or two, especially during periods of high usage. Have a professional check and clean your equipment once a year.

If the unit is more than 15 years old, you should consider replacing your system with one of the newer, energy-efficient units. A new unit would greatly reduce your energy consumption, especially if the existing equipment is in poor condition. Check your ductwork for dirt streaks, especially near seams. These indicate air leaks, and they should be sealed with a duct mastic. Insulate any ducts or pipes that travel through unheated spaces. An insulation R-Value of 6 is the recommended minimum.

Lighting

Energy for lighting accounts for about 10% of your electric bill. Examine the wattage size of the light bulbs in your house. You may have 100-watt (or larger) bulbs where 60 or 75 watts would do. You should also consider compact fluorescent lamps for areas where lights are on for hours at a time. Your electric utility may offer rebates or other incentives for purchasing energy-efficient lamps.

Learn More

Evaluation Tools

• Home Energy SaverLawrence Berkeley National Laboratory
• Home Energy CheckupAlliance to Save Energy

Financing & Incentives

• DOE Weatherization Assistance ProgramOffice of Energy Efficiency and Renewable Energy

Reading List

• Krigger, J.; Dorsi, C. (2004). Residential Energy: Cost Savings and Comfort for Existing Buildings. Helena, MT: Saturn Resource Management.

Reprinted from http://www.eere.energy.gov/consumer/your_home/energy_audits/index.cfm/mytopic=11170
EERE copyright: “Materials on the EERE Web site are in the public domain. EERE requests that it be acknowledged as the source in any subsequent use of its information.”
See http://www1.eere.energy.gov/webpolicies/ for more information on copyright