Buildings of the world consume:
40% of the world's energy & materials
25% of the wood harvested
17% of our water

The average American house uses:
13,127 board feet of lumber
6,212 square feet of sheathing
2,000 square feet of flooring

In the U.S., buildings account for:
36% of total electricity consumption
62% of electricity use
30% of greenhouse gas emissions
37% of ozone depletion potential
And, ironically enough, most of us spend 90% of our time indoors.

Much of the environmental damage caused in the last hundred years is a direct result from how our buildings are built. This means that architects, designers, and in fact all building professionals are in a position to affect great change on our environment. But they need to know that consumers and occupants of buildings are demanding buildings that are more environmentally responsible.

“Green building” (also known as "sustainable," "ecological," and "eco-designed") is a way of designing and constructing buildings to redue energy use, conserve water, improve indoor air quality, and reduce dependence on our natural resources. Although the basic concepts for green building have been around for decades, only in the last few years have we seen the explosive growth in the greening of the construction industry.

Once only of interest to hard-core environmentalists, the rise in energy prices, our dependence on fossil fuel and growing concerns over our natural resources and indoor air quality has boosted green building into the mainstream spotlight.

Today, those in the business of designing and constructing buildings are faced with the new challenge of environmental responsibility. The rise in energy costs, shortage of building materials and growing consumer demands are driving this market to seek out better and more efficient ways to build our buildings. Increasingly, new legislation, stricter building codes, and rising health costs are forcing builders to build green whether they want to or not.

More important than any statistic however, is the good feeling you have when you know you've done what's right for both your family and your community. Promoting continued health, financial savings, and social responsibility, green building is the construction standard for the future, and the smart solution for today.

Green Buildings are sited, designed, constructed and operated to enhance the well-being of occupants, and to minimize negative impacts on the community and natural environment. With most of us spending more than 90% of our time indoors, green building is a healthier choice for a better indoor air. In traditional construction, the quality of our indoor environment is often far more polluted than outdoors due to the building materials, inadequate lighting, and a variety of other variables.

But perhaps the best justification of Green Building is how you cannot afford to not employ green principles. The occupants and owners of a building are losing money on every green feature they did not employ. Architects are in a position to save their clients a great deal of money in the operational costs of a building. After all, a great deal more will be spent on the operations, maintenance and employees in a building than ever was spent upon initial construction costs.

Basically, ask questions so that you understand if the builder is or is not knowledgeable about green building. This will help you assess whether they are trying to deliver a home that is higher quality than what you typically see in the marketplace: a green home that is energy and water efficient, durable and easy to maintain, and provides healthier indoor air quality for your family. You will quickly see if the builder is able to answer these questions with ease or not.

Some sample questions to ask:

• What are the green features that you have in your basic homes? Can you explain each of them to me?
• How many points on the Build It Green GreenPoint checklist does your basic home achieve and will you give me your filled out checklist noting the particular features? (Note: Some cities require a certain number of points for new homes in their area. Find out if the builder is just doing the least required or if they are going beyond the minimum.)
• What are my green options that I could choose to add beyond your basic offering and can you explain their benefits to me?
• What is in the home to make it more energy efficient than what is required to pass California's minimum Title-24 energy efficiency standards? or, What percentage above Title-24 standards is this home?
• What types of native and drought-tolerant plants, and high efficiency drip irrigations systems are you using on the homes, so that I will not have to spend as much money maintaining my landscape? Go to the Bay-Friendly Gardening website for more information.
• What features are you using to maintain good indoor air quality in this home? Answers you are looking for are: high efficiency pleated media air filters; No-VOC paints (250 grams/liter is already required by law - ask for no more than 150 grams/liter); super low-VOC wood finishes; super low VOC construction adhesives; cabinet and shelving materials with reduced formaldehyde; a sealed combustion furnace and water heater, a whole house vacuum system, hard surface flooring like tile, natural linoleum, bamboo, and stained concrete.
• What features are you using to consider our dwindling supply of natural resources when building this home? Answers you are looking for are: the significant use of engineered framing lumber; high recycled content insulation; recycled content tiles, lumber certified by the Forest Stewardship Council (FSC); recycled-content carpet, 100% recycled composite deck lumber, native and drought-tolerant plants using drip irrigation systems, a recycling center built into the cabinets.
• What features are you using to make this home energy efficient? Answers you are looking for are: an overall energy package that is 15% over Title-24 minimum energy code, insulation above code levels, high efficiency furnace (90 AFUE or higher), high efficiency air conditioning unit (12 SEER or higher), tankless water heaters, all Energy Star rated kitchen appliances, fluorescent light bulbs, a whole-house fan, ductwork sealed with mastic, ductwork located within the conditioned space, radiant barrier roof sheathing, planting of shade trees, and a whole-house performance test.
• What are the top things I can do NOW to green my home without spending any money? First, before doing any construction and spending any money, you can immediately start operating your home with efficiency in mind.

Save energy by:

• turning off lights, TV, or stereo when you are not in a room
• using ceiling fans to cool yourself, and turning them off when you are not in the room
• don't overheat or overcool your home, and adjust your thermostat for when you are not home

Save water by:

• not running water from any fixture when you are not using it directly
• checking the timing schedule on your irrigation system and only running it when needed (early morning is often best)
• washing only full loads of laundry or dishes, or setting the water level to the appropriate size of the load

Improve indoor air quality by:

• taking your shoes off when you enter the home or using a sturdy welcome mat (shoes bring in most of the dust and particles that are in your home
• running your bathroom and stovetop exhaust fans to remove humidity and fumes
• keeping cleaning materials, pesticides and other hazardous chemicals safely stored in the garage rather than inside the home near the children. When you do buy these materials next time, try buying ones which are less toxic

Lead a greener lifestyle by:

• preventing waste before it starts, only buy what you need
• look for products that have are made of recycled, non-toxic materials (and preferably are manufactured closer to where you live, to reduce the use of fossil fuels used to transport products long distances)
• being conscientious about recycling and reusing as much as you can
• start composting your kitchen and yard waste instead of throwing it out

That's the most common question people have about green building. A first response is to ask "cost more than what?" Does building "better" cost more? Or does building a more attractive home cost more? The answer is sometimes yes and sometimes no. It all depends on what you are comparing it to and what "it" is that you want to get for your money.

“Green” building cannot be easily defined as costing more or less than "standard" building, because standard building has an unlimited range of prices just like green building can have. There is not an easy or simple side-by-side comparison. A building is a gigantic mix of costs associated with design, systems and materials choices, construction methods, and operational methods, determined by a multitude of decisions that must be made by the designer, builder, or owner. Costs vary based upon the design, the materials used, the places where materials are purchased, who assembles them and how. This is true of green or standard building.

Having said all of the above, we can also say that the debate over whether green building costs more has generally been settled. While there may be some additional upfront costs associated with "greening" a building, those costs will be more repaid via cost savings-often in a fairly short period of time (especially when you consider the likelihood of continually increasing energy and water costs). Investing in green features saves money, because energy efficient homes generate increased value and durability, while lowering utility bills and maintenance costs. It may also be possible to qualify for a higher loan amount for a lower monthly cost. Examples of other first cost or operational savings include:

• Advanced Framing Technique - providing more insulation while saving on lumber costs. Extra Energy Efficient Building Shell - going beyond code, the shell provides a quieter, more comfortable interior that reduces energy use and lowers energy bills.
• Passive Solar Siting and Design - uses nature's free energy to supplement heating and lighting and reduce utility bills. Radiant Floor Heating - generating an ambient temperature of 65 degrees can provide the same comfort as a forced air system generating an ambient temperature of 72 degrees, shaving 20% to 40% off heating bills.

For more on this subject, here are almost 50 references to cost/benefit studies of green building.

For the past four years in the Bay Area, there has been a training and certification program for Green Building Professionals produced by Build It Green (BIG). These professionals have shown an interest in green building by getting an education in the field with the goal of delivering a better home to you. You can download the names and contacts of the graduates of this program at The Certified Green Building Professional Directory.

BIG encourages members and graduates to put the Build It Green logo on business cards, yellow pages listings, newspaper advertisements and brochures. When a building professional displays the logo it means he or she has taken the extra effort to join Build It Green, to rate their building projects and to attend continuing professional education. See the factsheet on “Choosing a Green Building Professional”

If you have already selected a builder and they are not educated on green building you will have to work a bit harder to get what you want.

• First, try to get them to take as many training and certification classes as they can, because it will help your cause and the builder's professional education. See Training opportunities.
• Second, download the new home, home remodeling, or multifamily guidelines and checklists from our web site, give a copy to your builder, ask her/him to read it, and read a copy yourself.
• Third, try to follow the guidelines as much as possible and use the fact sheets, materials database, and free Ask an Expert service at Build It Green.

There is a lot at stake in choosing a building contractor for either a big or even a small job, because you are spending a lot of your hard-earned money, are expecting to receive a product or service that is going to last for a long time, and installation may take a long time, making your relationship pretty close for quite a while during construction (and after to handle any follow-up).

• First, take the time to thoroughly research and plan exactly what you'd like to do in your project, and why.
• Second, interview a number of contractors to understand the wide array of professionals available (also ask friends for recommendations of good contractors). You can also find a list of Certified Green Building Professionals on this web site. During the interviews: see if they are properly licensed and insured; get references of past clients and definitely call them; ask to see photos and/or visit past jobs; ask them if they know about green building practices; ask for their advice on your project and how they would approach the job, and then ask for a written bid from the contractors with whom you feel the most comfortable.
• Third, as you review the bids and the contractors, be sure you and they are clear on what it will cost, what will be done, how it will be done, what happens if things go wrong in the process, how are change orders handled, and what guarantees and warranties will you have that the work will be completed to your satisfaction. Most problems between contractors and homeowners are a result of a homeowner not doing good research to pick the best contractor for their job and a lack of good communication between the contractor and the homeowner resulting in differing expectations. Construction jobs will always have some problems along the way, but the key to picking a good contractor is how well she/he will resolve those problems. Remember that, more times than not, you get what you pay for and headaches, problems, and bad communication can cost a lot more money than the initial bid price.
• Fourth, take a deep breath. When you feel comfortable with everything: make your choice, read your contract thoroughly, ask questions before you sign, and then maintain good communication with your contractor to keep things running smoothly.

There are a number of outlets for training and certification. Visit Build It Green’s factsheet on educational opportunities in California.

Look for the Petaluma Build It Green logo on the builder's marketing materials. We are just beginning our rating program, so you will soon start to see rated new homes on the market.

A green home can look like your present home or any other home. It may be a single-family home, a condo, or an apartment. The green features generally don't show themselves so prominently, but tend to be subtle or even hidden. A great way to discover this is to make sure and attend the biennial Build It Green Home Tours. These tours feature beautiful new and remodeled green homes, apartments, condos, in many counties in the Bay Area. There are also many case study examples of green buildings in Sonoma County, northern California and throughout the U.S.

Green building adheres to higher building and material standards than conventional construction, which translates to overall improved performance of the home and increased homeowner satisfaction. Petaluma Build It Green promotes these products, practices and systems so you can save money, time, and environmental resources through reduced maintenance, replacement, and energy costs.

Features that might be included in a home built following green building criteria are:

• Extra Energy Efficient Shell - going beyond code, the home provides a quieter, more comfortable interior that reduces energy use and lowers energy bills.
• Healthier Paints, Sealers, Adhesives and Solvents - less-toxic formulas reduce exposure to harmful chemicals.
• Controlled Ventilation and Filtration - provides a safer and healthier indoor environment by filtering out allergens and preventing moisture from collecting inside walls and crawlspaces (standing moisture could result in potentially dangerous mold).
• Natural Alternatives to Wood Flooring - in flooring and countertops, materials like bamboo, cork, and linoleum offer a natural look while being more stable and more long-lasting than conventional products.
• Innovative Bio-Composite Products - new products made from a mixture of natural and artificial materials add more durability to homes while still maintaining their natural look.
• Recycled-Content Ceramic Tile - performs like conventional ceramic tile, but utilizes typically wasted materials.
• Fiber Cement Siding - lasts 30 years longer than conventional siding products and is significantly easier to maintain. Healthier Insulation - a variety of options are available including less-toxic, recycled content, and high-density insulations.

Since it's founding in 1991, the U.S. Green Building Council (USGBC) has emerged as the recognized national professional organization for people involved in green building.

To help the construction industry define green building, the USGBC developed a method of scoring buildings to evaluate their "green-ness." LEED (Leadership in Energy and Environmental Design) is their green building rating system, which defines a voluntary guideline for developing high-performance, sustainable buildings.

LEED has become the industry standard for commercial green building in the United States. (For single and multifamily residences, we use the Build It Green GreenPoint Rated system.) Today, LEED buildings can be found in 12 countries and all 50 states. There are currently over 20,000 LEED Accredited Professionals trained in this rating system and nearly 2,000 buildings on their way to certification.

The LEED system works by dividing the building into five categories: Sustainable Sites, Water Conservation, Energy & Atmosphere, Materials & Resources, and Indoor Environmental Quality. LEED lists opportunities for a building to earn points in each. The final number of points determines the green level of the building, rated as Certified, Silver, Gold and Platinum.

To date, LEED has been adopted by 8 federal agencies, 20 states and 41 U.S. city and county governments as the green standard in the construction of all civic facilities. To find out more about LEED, visit USGBC.

The Build It Green New Home, Remodeling and Multifamily Guidelines and the GreenPoint Rated system have been adopted and referenced by many city and county governments in California.

Research has shown that 83% of designers feel they have a responsibility to offer green solutions to their clients, but only 17% actually do so. They blame this difference on “not enough information.”

In truth, the construction industry represents 20% of the U.S. economy, comprising $1.27 trillion of our gross domestic product. With such large amounts of money and influence, the construction industry is inherently risk adverse. We have been building our buildings in relatively the same fashion for the last hundred years. What is the incentive for an architect, contractor or developer to add risk?

Luckily, the numerous benefits within green building are causing the industry to take notice. The initial acceptance was towards green finishes, where the risk is low. After all, it is the same exact process to install a bamboo floor as an old growth wood floor.

The next wave of adoption was in systems to add to the building. Solar panels can be placed on the roof without much risk. They are simply added to the project much in the way one would add a heating system.

The final surge in acceptance is now being seen in architectural design and structural systems of the building. This final obstacle is slowly being overcome as developers realize a stick frame building in Minnesota is different from a stick frame building in Arizona.

Afflicts about 20 million Americans, including 6.3 million children. In fact, asthma, once rated seventh, is now the leading chronic illness in children. Since 1980, the biggest growth in asthma cases has been in children under five. In 2000 there were nearly 2 million emergency room visits and nearly half a million hospitalizations due to asthma, at a cost of almost $2 billion, and causing 14 million school days missed each year.

One of the primary causes of asthma is bad indoor air quality. The toxic chemicals found in most common building materials have been linked to asthma and other respiratory problems. The importance and need for green building is increasing exponentially as our health is affected.

Indoor pollution sources that release gases or particles into the air are the primary cause of indoor air quality problems in homes. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the home. High temperature and humidity levels can also increase concentrations of some pollutants.

There are many sources of indoor air pollution in any home. These include combustion sources such as oil, gas, kerosene, coal, wood, and tobacco products; building materials and furnishings as diverse as deteriorated, asbestos-containing insulation, wet or damp carpet, and cabinetry or furniture made of certain pressed wood products; products for household cleaning and maintenance, personal care, or hobbies; central heating and cooling systems and humidification devices; and outdoor sources such as radon, pesticides, and outdoor air pollution.

Apart from controlling the materials inside a building, the best way to control indoor air quality, especially in existing buildings, is through an increase in natural ventilation. With a lack of fresh air, pollutants will accumulate to levels that can pose serious health and comfort problems. The consequences of poor indoor air quality go beyond mere comfort issues and extend into that of our future health.

How long do flex-ducts last?
There really isn't any mold or allergy concerns with flex duct over sheet metal as a material for duct work. However, if you are putting flex duct in an attic or a crawl space, understand that flex duct has a 12-15 year life expectancy, and consider what happens when pests get into these spaces. You can expect sheet metal to last the life of the building. Flex duct should not be used in commercial or institutional buildings.

If you air seal all the openings in a house, doesn't that allow radon, dust, and carbon dioxide to build up to dangerous levels inside the house? I've always been told that a house needs to “breathe”.
It is true that a house needs to exchange outdoor air at fairly regular intervals. However, in most homes, many of the holes and leaks that might bring in outside air actually draw that air in through basements, wall cavities, crawlspaces and attics. These are areas that can have extreme temperatures, humidity, insulation dust, insects, mold and other particles that nobody would want in the air that they breathe. The reason for building an airtight "building envelope" that contains all the livable space in the house is to make sure that all of the air that is brought in is controlled. Air that is brought in through controlled channels is able to be filtered, dehumidified, and adjusted to the proper temperature, all of which saves energy and results in a healthier, more comfortable home. For more information, please visit the following page for the US Department of Energy's Air Sealing factsheet.

I sometimes get standing water on the dirt floor of my crawlspace, and I'm starting to worry about mold appearing.
There are a number of steps to take to eliminate the water getting into your crawlspace. Because moisture is the cause of mold, the first step is to make sure that rainwater is being directed as far away from the house as possible. The soil next to the foundation should have at least a 5 percent grade sloping away from the house, and gutters should release water approximately 8 to 10 feet away from the house. Also, make sure that the gutters and downspouts are not disconnected or leaky, because this can lead to puddles forming next to the foundation, which can then leak into the crawlspace. The next step is to put down a continuous, sealed layer of 6-mil, or thicker, polyethylene plastic sheeting on the floor of the crawlspace. It is important to seal the plastic to the wall and any seams in the plastic to insure that moisture rising from the soil is prevented from entering the crawlspace.

Mold indeed is a health hazard and can be remediated by a contractor or can usually be a do-it-yourself project if the area is less than 10 square feet. However, if there has been substantial water damage and/or mold growth covers more than 10 square feet, consult the U.S. EPA guide: Mold Remediation in Schools and Commercial Buildings. Although focused on schools and commercial buildings, this document is applicable to other building types such as homes. Some mold cleanup tips: fix plumbing leaks and other water problems as quickly as possible; scrub mold off hard surfaces with a detergent/water mixture and dry completely, clean/dry moldy surfaces before painting. Porous materials, such as ceiling tiles and carpet, may have to be thrown away if they become moldy, due to the mold growing into the empty spaces and crevices in the material. Above all, take precautions while cleaning up by wearing a protective gear including a respirator, gloves and eye goggles.

A HEPA (High Efficiency Particle Arresting) filter can remove the smallest pollutants from the air stream flowing through the home's air handler. These filters are rated up to 99% efficient in the removal of indoor air pollutants. They are, though, incredibly restrictive to air flow and can severely inhibit the function of your heating/cooling system if the system is not designed to handle them. Other filters, such as electronic, electrostatic, and pleated media fabric types will filter the air at various stages of efficiency that will perform very successfully for your system without extra engineering (stay between a filtration rating of MERV 6 and 12 for the best performance with the least problems). A good filter improves indoor-air quality as well as protecting the equipment. Better air means fewer respiratory ailments and allergies. Learn more from our Factsheet on Air Filters which has a complete discussion of which filter is best for your family.

Blown-in or foamed insulation ("total-fill") and advanced sealing and weather stripping are effective methods for tightening a home. These techniques reduce unwanted air infiltration and the loss of conditioned air. Sealing the home with an advanced sealing techniques (new construction) or with basic sealing from the inside (existing home) can make a big difference in heating/cooling bills and overall comfort, as well as reduce the infiltration of outside pollutants, such as dust, pollen, molds, carbon monoxide, odors, and excess humidity.

Traditional particleboard is made with urea formaldehyde resin (glue) that is considered a human carcinogen. An alternative is an MDF that uses a resin that is formaldehyde-free. This MDF can be made with wood sawdust or with straw. As a last resort, one can also use at least two coats of a good sealer (to lock in the formaldehyde somewhat) on all six sides of every panel of plywood, particleboard or MDF used in the cabinetry.

Less-toxic finishes are typically water-based finishes that are very low odor, or contain few or no unhealthy volatile organic compounds (VOCs)

Less-toxic typically refers to lower VOCs (typically measured in grams per liter). Old adhesives tend to be solvent-based and high VOC (250-800 grams/liter). Today, you can easily buy equally or better performing adhesives that are water-based and range from 0 to 250 grams per liter VOC. Always consider health issues and look for the lowest VOC level you can get in any product (adhesives, paints, sealers, caulks, etc.).

VOCs or volatile organic compounds are a very large class of chemicals that offgas malodorous and often unhealthy fumes. Common chemicals in this group for paints are toluene, benzene, acetone, and formaldehyde, while for particleboard it is formaldehyde.

Paints offgas as many VOCs as they can in a short period of time. It is said that paints offgas 80-90% of their VOCs within a couple of weeks of their application, while the last 10-20% offgases over the next year rising during times of higher temperature and humidity. The VOCs are transported into the air to be breathed in by occupants, attached to soft materials such as clothes, drapes, furniture and carpeting, and dissipated to the outdoor air to help cause low level smog. Ways to avoid VOC are to buy paints with very low or no VOCs at all. Federal standards require water-based paints to generally be under 250 grams/liter in VOC content and oil-based paints to be under 380 grams/liter in VOC content. Water-based paints have improved radically over the last few years in quality and there are few reasons to use oil-based paints anymore. We like to recommend and personally only use no-VOC paints for wall and ceiling painting. All of the major paint manufacturers make a no-VOC paint and they have all improved their formulations significantly to the point where these are some of the highest quality paints.

Particleboard is made with urea formaldehyde based glue, which it is said offgases fairly slowly over many years; some people say seven to ten years. Due to voluntary regulations and some customer pressure, the levels of formaldehyde have been reduced by most manufacturers, but they can still be significant to sensitive people. Some manufacturers have taken pains to alter their glues and some even have formaldehyde-free glues that they use. A nice thing to recommend is a formaldehyde-free medium density fiberboard (MDF), which is a denser form of what you may know as particleboard typically used for cabinets and shelving. It is more expensive than standard particleboard, but it is a high quality product, and is a small cost in the assembly of the entire cabinet considering how much labor is typically used in a job versus the materials.

As an overall direction, we like to promote the concept of "prudent avoidance" in dealing with chemicals from building materials. We know many of these chemicals range from little to very unhealthy, but the science has not and will probably never be able to tell us exactly how safe or harmful they are, so why not just try to avoid them in the first place whenever you can. We'd have some better answers if the scientists could convince some humans to be willing to live in a lab for 20 years and be tested for all of these chemicals and their various mixtures, but they have not had many volunteers.

The Consumer Energy Center has many tips, fact sheets, videos, and other resources to help any home or building become more energy efficient.

Are there advantages/disadvantages of each, and in what circumstances are each recommended?
There is quite a difference involving attic fans and whole house fans, in both form and function. Whole house fans are much larger in size and are placed somewhere in a central location of the house's ceiling. These fans are an efficient way to cool a home, moving a decent amount of air through the house and up to the attic area. They can be run at all times during warmer months, but are most efficient when outside temperatures and humidity levels are not extreme enough to warrant using an air conditioner. This is because a whole house fan can only cool the interior of a house to the outside temperature and cannot dehumidify the inside. Another possible drawback to operating this fan is that they can also draw in outside dust and pollen. See a good Department of Energy factsheet on whole house fans.

Attic (or roof) fans are usually much smaller in size (although sometimes not) and are usually placed on the interior roofline of a house. These fans are intended to circulate heated air from the attic space to the outside, but they can be overpowered and can create negative pressures in a home, removing conditioned air from the house through ceiling leaks and bypasses. Roof fans are generally not recommended for most house designs. Instead, we recommend passive venting via continuous soffit and ridge vents. See a good Department of Energy factsheet on attic ventilation

Studies have shown a typical duct system leaks from 20-40% of the heated air that's supposed to be getting to the rooms of your house. This is bad for your comfort and energy bill, but it could be worse for your health and safety. A leaky duct system can create pressure differences in your heating system that can draw in contaminants like dust from the attic, excess humidity from the outdoors, soil gasses from the crawlspace, or flue gases from the fireplace or gas hot water heater. The duct system should be sealed at all joints and penetrations with brush-on, low-VOC, water-based mastic, rather than less effective duct tape. The ducts should also be professionally tested for leakage (with a "duct blaster" machine) and achieve a leakage rate of less than 6%.

The Home Performance Rating is the state recognized home energy rating system (HERS) in California. Trained Home Performance Raters use uniform, nationally recognized guidelines to review a home's energy related components (levels of insulation, types of windows, local climate, efficiency of mechanicals, utility rates, etc.) and issue an energy rating for a home. Upon your request, the rater can additionally use a testing devices to see how leaky your home is, how leaky your ducts are, if the proper airflow is coming from each duct register, and if your HVAC system is backdrafting dangerous combustion gases. Measured on a scale of 1 to 100, the rating scale indicates how energy efficient a home is, with higher scores meaning greater efficiency. Like a miles per gallon figure for a car, the rating gives homeowners and homebuyers a basis for comparing the energy efficiency of various homes. Over time the rating score can be used as an indicator of additional value for a home that is energy efficient.

Good passive solar building design takes advantage of the sun's "free" energy to help heat your home and in turn, save you energy. Solar water heating is already cheaper than using electricity to heat water. Solar electric (photovoltaics or PVs) is becoming more affordable especially with today's state rebates. To find out more about solar energy, visit the California Solar Center or the Northern California Solar Energy Society

Most heat is lost from pipes close to the water heater (within six feet), where the temperature is being maintained at the water heater's set point. The higher the temperature, the greater the heat loss through uninsulated pipes. It's similar to cooling a hot cup of coffee more quickly by putting a metal spoon in it. Look for readily available water heaters with an Energy Factor (EF) of at least 0.60 and use hot water insulation blankets and pipe insulation to minimize energy loss. In a typical home, your water heater is heating water 24 hours a day, 365 days a year, therefore even slight increases in efficiency are an important improvement. Another option is to use an on-demand or tankless water heater that only heats water exactly when you open a faucet.

Energy Star is a government-backed program helping homeowners and businesses protect the environment through superior energy efficiency. Energy efficient choices can save families about a third on their energy bill with similar savings of greenhouse gas emissions, without sacrificing features, style or comfort. If looking for new household products, look for ones that have earned the Energy Star. They meet strict energy efficiency guidelines set by the EPA and US Department of Energy. If looking for a new home, look for one that has been built and tested to earn the Energy Star designation. See Energy Star for answers to all you questions.

Perhaps more than any other building components, windows have seen a significant increase in performance resulting from new technologies, from "low-e" glass coatings to gas-filled windows. While high performance windows may cost slightly more, when the rest of the home's heating system is adjusted accordingly, these costs can be offset and the on-going energy savings will pay back that extra cost more quickly. However, the most frequent selling point for these high-performance windows is the added comfort over a standard window. To find out more about high performance windows, visit Efficient Windows Collaborative.

That depends on how much energy it is using right now, how much you want to reduce your energy use, and how much you are willing to invest at your personal “cost-effective” criteria. The most cost effective way to reduce energy for any building is to take a look at your personal habits and your personal perception of your comfort level, which are by far the largest determinant in energy use for any building. It is totally free to adjust the thermostat setting down in the winter and up in the summer. For example, depending on the weather and your particular home design and heating/cooling system you can lower your energy costs by 3-14% for every degree you move up on your summer thermostat from 72 degrees. That's a lot of money for simply adjusting the thermostat. Another easy habit in the summer is to try to cook outdoor on the grill rather than indoors in the oven or on the stove, thereby not heating up the home.

For your old home, you probably don't have insulation or double-paned windows anywhere, so your heating and cooling are probably working pretty hard to keep up with the thermostat setting. Adding insulation to the ceiling or attic floor is a very inexpensive action to take. It will keep the warmth from escaping up and out during the winter and during the summer, it will reduce the hot attic temperatures from coming down into the living space. Adding insulation to your walls can be a pretty expensive proposition, but may be worth it for comfort sake rather than just an energy savings sake. Upgrading your windows from single-pane to double pane is not cost-effective for energy sake, but may be worth it for you in terms of added comfort in the winter and in exterior noise reduction.

Caulking, sealing and weatherstripping the leaks around the home is also very inexpensive and can be done by the homeowner. Install good weatherstripping around all doors, windows, and attic or basement access hatches. Caulk or use canned minimal–expanding foam around every light switch, outlet, air duct register, window, door, plumbing penetration, dryer vent, chimney and water heater flue, etc. It is also cost-effective to have your heating and cooling equipment serviced to make sure it is operating safely and effectively. You can also have your equipment tested for tightness and then repaired based on the results. On average, nationally, ductwork leaks about 25%. That means you are wasting 25% of your conditioned air into your neighborhood.

Other easy things to do for summer savings are to protect your home from the sun coming in too strong through your windows and heating up your home. In the winter, you like the sun coming in to warm up the home, but in the summer, this is by far the number one reason that a home is uncomfortable. It is inexpensive to get solar screens that block about 70% of the heat coming through the windows and that dually act as bug screens. You can take these off in the winter and let the maximum sun come in during those months. Planting deciduous trees to block some of the sun also works great, so that the leaves block the sun during the summer and the when they fall in the fall and winter, they allow the sun to get to the windows. Another easy summer savings comes from installing ceiling fans, which do not change the temperature, but make you feel cooler with the breeze, which consequently allows you to be equally comfortable in 3–4 degrees higher temperature than without the breeze. In addition, installing a whole house fan in an upstairs hallway can allow you to flush all of the hot air in your home in the evening and bring in cooler outdoor air. A final easy summer technology is the installation of a radiant barrier, which is a roll of sturdy aluminum fabric that is stapled to the underside of the roof rafters to block 95% of the radiant heat coming from the hot roof and pushing through the attic insulation into your living space. We could go on and on with inexpensive tips, but for more information on saving energy in your home visit Pacific Gas and Electric.

Do not discount all fluorescent lights yet, because there are many options in the market. Residential lighting is generally limited to being sold in three forms; incandescent (the typical "light bulb" that has barely changed in form nor improved much since Thomas Edison), fluorescent (the familiar 4 foot tubes, circles and ever-expanding varieties of compact shapes), and halogen (the small bright hot lights). They each have different characteristics; fluorescents are for ambient lighting and use the least energy, halogens use twice as much energy and are used for clear, short distance spot or task lighting, while incandescents use three to four times as much energy and are used for general task lighting. Halogens and incandescents use a lot of their energy in producing heat in the fixture and room (80-95% of their electrical energy goes into heat).

The input energy used for creating the light is measured in watts. The amount of visible light output is measured in lumens. The lumens-to-watt ratio is the efficacy. Energy efficiency is measured by how much light one gets for the amount of energy input. You can be energy efficient by: using higher efficacy lights, installing the appropriate lights for the appropriate use and location, focusing or reflecting lights, dimming lights, using light or motion sensors, and not using lights where they are not necessary. Light quality is measured by a combination of color rendering index (CRI) and color temperature. CRI is measured on a 1 to 100 scale, indicating how well the light represents true color; sunlight is rated 100 CRI, incandescent bulbs measure 90-98, older, cool white fluorescent lights that make your skin look sickly blue measure about 50, while new fluorescents measure up to 95. So, when buying lighting, you should generally look for a higher CRI.

Color temperature of the light output is measured in degrees of Kelvin (1500-6000K) and that measure indicates a yellow, white or blue type of light. Choose a temperature based upon the softness or crispness that you desire; lower K (1500-2500) is yellowish and warm, mid K (2500- 4000) is whiter and cooler, and high K (4000-6000) is bluish and starkly bright. Choose your temperature based upon your desired feel in the room. You should know that you have a lot of choices and can choose lights with any combination of watts, lumens, CRI and Kelvin to get different effects both in energy use, light quality, and your task effectiveness. You have to design your lighting to do what it is intended to do; too much or too little light is not right and neither is a quality of light that is not appropriate for your use. Much of this is hard to explain in words, so before you just buy whatever is available on the standard big box store shelves and feel that that is your small range of choices, first go to a dedicated lighting store that has extensive displays and get some experience in seeing what different types of lighting can do. You will get so much more education in how lighting works than by reading information on it. If you do want to read some more check out Energy Star.

Radiant barriers are installed in homes-most commonly in attics-to keep your attic cooler and lower cooling costs. In hot climates, the benefits of a radiant barrier include both dollar savings and increased comfort. The barrier consists of a highly reflective material that blocks most of the radiant heat of the sun from penetrating your attic and home.

Without a radiant barrier, your roof radiates solar-generated heat to the insulation below it. The insulation absorbs the heat and gradually transfers it to the material it touches, principally, the ceiling. This makes your air conditioner run longer and consume more electricity.

Is there a way to tell if it's oversized by how long it runs?
A house's orientation, shade, window area, insulation and air leakage can dramatically affect heating and cooling needs. Standard guidelines for sizing equipment for today's homes often result in a mismatch. Insist that equipment be sized according to the Air Conditioning Contractors Association of America (ACCA) Manual J, or similar procedures. Sizing equipment by simple rules-of-thumb methods (for tons of air conditioning or BTU of heating per square foot of living area) isn't acceptable.

On-demand water or tankless heaters heat water directly without the use of a storage tank. They avoid the standby heat losses associated with keeping large amounts of water hot. When a hot water tap is turned on, cold water travels through a pipe into the unit. Either a gas burner or an electric element heats the water. As a result, demand water heaters deliver a constant supply of hot water. Typically, demand water heaters provide hot water at a rate of 2-5 gallons per minute. Don't forget to also consider a solar water heater. Learn about them through our Solar Water Heating factsheet.

Today, with green building becoming very popular, almost all manufacturers and product and service suppliers want to make the case to you that their product is green. The reality is that this is not the case. It is up to you to become an educated consumer and to decide which product or service seems right for you. The Petaluma Build It Green Program subscribes to the definitions of green that follow established green building industry standards set over time by credible organizations such as BuildingGreen. BuildGreen's definition of green products are those that:

1. Conserve Natural Resources
2. Are Made with Salvaged, Recycled, or Agricultural Waste Content
3. Avoid Toxic or Other Emissions
4. Reduce Environmental Impacts During Construction, Demolition, or Renovation
5. Save Energy or Water
6. Contribute to a Safe, Healthy Indoor Environment

For a detailed description of the above definitions, please refer to Build It Green

It is no longer difficult to find beautiful, sustainable building materials. Many materials are available at your standard building material supply outlets. Your newer green options range from the traditional natural linoleum to recycled glass tile, recycled rubber roofing and sustainable harvested lumber. You can use the latest technologies or 100-year-old salvaged materials to achieve high-performance, healthy and low-impact remodeling and building. Check out the AccessGreen Directory) for listings of hundreds of products and retailers in the Bay Area.

Green materials that deal with the obvious health, safety and welfare of the inhabitants (like the walls, floors and beams) need to be code approved just like any other material. That said, most materials are already code approved or do not need code approval, otherwise they would have a very hard time existing very long in the marketplace. If you want to do something very unusual, though, it is always best to check with the Community Development Department (778-4301).

Buying regional products reduces transportation costs and energy, and keeps dollars in the local economy. A major tenet of sustainability is making use of resources from the immediate region.

First, you are looking for products that answer one or more questions comfortably for yourself:

1. Will this product make my home more energy efficient and/or comfortable?
2. Will this product save water?
3. Is this product safe for my family when I use it or after it is installed? (will it offgas harmful chemicals?)
4. Is this product durable so I won't have to keep replacing or repairing it frequently?
5. Is this product made from recycled materials?
6. Is this product manufactured in an environmentally-friendly way?
7. Is this product made locally?

Second, you should read the Build It Green Home Remodeling Guidelines posted on this site to familiarize yourself with most of the issues in green building.

Third, you can go to the AccessGreen Directory linked from this site to (Build It Green and search (in any of three different ways) for any type of product you might be looking for. The database will list the product and the retail location where you can purchase it.

Fourth, when you are in the stores where you normally buy products for your home, ask the store staff or management what types of green products they carry, do they have a list of them, and are they are a member of the Build It Green organization which works with other retailers in educating consumers about green building. The stores will respond with more green products only if they know that customers are asking for them!

Yes, but typical green home criteria advocate the use of domestically harvested hardwood, reused wood, rapidly renewable flooring (like bamboo), or FSC certified sustainably harvested wood.

Bamboo is a highly renewable resource, harvestable only four to six years after being planted, and offers the strength of typical oak hardwood floors. Prices for bamboo flooring products range from $4 to $8 per square foot, making them a bit more expensive than flooring from domestic hardwoods. The pre-finished products all use UV-cured finishes, which have low-VOC emissions. Any of these products should make an attractive, durable floor. Our Bamboo Flooring Factsheet will give you an education on this interesting new material in our marketplace.

Many factors are involved in determining the "greenness" of a product, and those factors must be weighed in relation to personal tastes and the specific requirements of the project. In determining the best options, consider what the use will be (high traffic entry, kitchen, children's playroom, bathroom, bedroom, etc.) and what your personal preferences are. Some people just love the feel of carpet, while others find it hard to clean and prefer hard surfaces that hold less dirt.

For new construction on a concrete slab first floor, a simple flooring is to just use the concrete slab foundation and have it steel troweled to a slick surface, then colored with a pigment, stain or acid, and then sealed with a clear sealer. "Green" floor finishes include carpet made with recycled polyester, nylon or even new natural materials like corn silk, sisal, seagrass, and wool. Tile is always a good choice for a durable hard surface, but you can go even better in the green department by buying a tile that is made from recycled materials. If you like the feel of wood, choose a local wood (to promote the local economy and reduce transportation pollution), a recycled wood (to reduce the stress on new forests), or a new wood that is certified by the Forest Stewardship Council (FSC) which certifies that the wood comes from sustainably harvested forests. The final recommendation is to choose a durable floor covering that comes from rapidly renewable sources such as bamboo, cork or natural linoleum.

Always look for flooring that is durable, and consider maintenance requirements. Choosing a product that is locally available or manufactured will reduce environmental impacts from shipping. A locally quarried stone may be an environmentally responsible choice for one site, while for another reclaimed wood from a nearby site may make more sense.

Finally, make sure other materials required to install or finish the product have low or no VOC content.

Sustainably harvested lumber is harvested using forestry practices that maintain the diversity of native species, while maximizing the quality and quantity of timber grown under sustained-yield management principles. These principles include developing a formal plan to ensure long-term forest management, minimizing the damage to the remaining forest during growth management and harvesting, protecting local biodiversity and watersheds, preventing over-cutting of popular timber species, planting trees on degraded or cleared land with an emphasis on a diversity of native species and ecosystem restoration, and developing positive relationships with local communities and workers. Consumers will encounter a number of organizations certifying lumber, but the system preferred by green building experts due to its strict standards and world-wide acceptance is the certification from the Forest Stewardship Council (FSC).

Engineered wood products use smaller, younger trees, avoiding the use of larger, older trees that are found in disappearing old growth forests. Engineered lumber achieves the same or better structural characteristics as solid dimensional lumber with 10-50% less wood material, again saving trees. Engineered wood products are also factory manufactured to be strong, light and straight, eliminating the waste associated with warped, twisted or otherwise unusable solid lumber.

A number of recycled-content deck products are currently on the market. They are typically made of 100% recycled plastic or a 50/50 mix of recycled plastic and waste wood chips or sawdust. These products are very low-maintenance and extremely durable. They require no annual application of sealers and they do not warp, twist, rot or splinter. It is an attractive, safer, cost-effective alternative to chemically treated wood and avoids the need for logging precious woods like redwood and cedar. See the factsheet.

Fiber-cement siding is made of a mixture of cement and some type of fiber (typically wood). Highly durable, it holds paint longer and does not warp, split, rot or get attacked by termites. Other durable, green building siding options include stucco and locally produced brick and stone. Long lasting, low maintenance exterior finish products reduce replacement frequency, resulting in cost savings, reduced landfill impact, and fewer resources devoted to maintenance and replacement.

Are there any that are considered generally better in all aspects?
There are many different types of insulation, from the common fiberglass batts to recycled cotton to spray-in foam, and each has its own advantages and disadvantages. The actual insulating value is measured in thermal resistance, or its R-value. The higher the R-value per inch, the better it insulates. However, how well your home is sealed from air leaks and how tightly the insulation fits in the walls or ceilings can also affect temperature and comfort. Ask your contractor to follow the CA Energy Commission’s Procedures for Proper Installation of Insulation.

Health and environmental effects can also vary between different types. There is a great article that covers the differences between insulation types from health, environmental, and insulating viewpoints from Environmental Building News

Painting is of the quickest ways to give your home a new look. Whether it's just a bathroom or the whole house, it's an easy way to remodel. Our Paint Factsheet) will help you make environmentally-sound choices when you select the paint for your next project.

Actually, one of the best ways to save water is outside your home. Our irrigated landscapes use 30-70% of our home's water. The first best thing to do is to improve your irrigation system operations by adjusting your timer to really only water when your plants need it. Most of us overwater our plants significantly. Second, run your system and adjust the sprinkler heads so that they actually hit the plant areas and don't spray the sidewalk or your driveway, so that your precious water just runs down the street. Third, you could add a rain or a moisture sensor to the system, so that the system does not irrigate when the soil already has enough water for your plants. Fourth, you could change some of your larger, broadcasting sprinkler heads to drip hoses and heads that feed water directly to the plant root area, rather than losing so much water to the leaves and the atmosphere via evaporation. Use some mulch to try and keep the water in the soil and reduce weed growth. Finally, start to look at your plantings and slowly begin to try reducing the amount of plants that are big water users and increasing plantings of native and drought-tolerant plants. Do a small section at a time so you don't get overwhelmed.

You can find all of this information and more in detail by downloading the Bay-Friendly Landscape Guidelines or Bay Friendly Gardening.