A green building is any building that is sited, designed, constructed, operated, and maintained for the health and well-being of the occupants while minimizing impact on the environment.
Green building construction refers to those practices that promote occupant health and comfort while minimizing negative impacts on the environment. There are different degrees of “greenness.” Often it is necessary to strike a balance between many different sometimes conflicting “green” options based on the particular conditions of a given project. For example, proper strategy for a sustainable retrofit
project may differ from that of new construction design.
Green building practices offer an opportunity to create environmentally sound and resource-efficient buildings by using an integrated approach to design. Green buildings promote resource conservation by including design features, such as: energy efficiency, use of renewable energy, and water conservation.
By promoting resource conservation, green building design creates healthy and comfortable environments, reduces operation and maintenance costs, considers environmental impact of building construction and retrofit, and concentrates on waste minimization.
In the interim, green building design addresses such issues as historical preservation and access to public transportation and other community infrastructure systems. The entire life cycle of the building and its components is considered, as well as the economic and environmental impact and performance.
Post-tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons. Post-tensioning applications are commonly used in office and apartment buildings, parking structures, slabs-on-ground, bridges, sports stadiums, rock and soil anchors, and water-tanks. In many cases, post-tensioning allows construction that would otherwise be impossible due to either site constraints or architectural requirements.
In building construction, post-tensioning allows longer clear spans, thinner slabs, fewer beams and more slender, dramatic elements. Thinner slabs mean less concrete is required. In addition, it means a lower overall building height for the same floor-to-floor height.
Post-tensioning can thus allow a significant reduction in building weight versus a conventional concrete building with the same number of floors. This reduces the foundation load and can be a major advantage in seismic areas.
A lower building height can also translate to considerable savings in mechanical systems and façade costs.
Another advantage of post-tensioning is that beams and slabs can be continuous, i.e. a single beam can run continuously from one end of the building to the other. Structurally, this is much more efficient than having a beam that just goes from one column to the next.
Metal roofs add energy efficiency and a reflective surface when natural metal or light colors are selected. They can enhance the look of your home and provide attic space/storage area.
A Metal Roof will increase the appraisal value of your home and last for years and years–far longer than a typical roof system. Aesthetically pleasing and energy efficient, metal roofs can be an enduring and attractive option.
High solar reflectance and high infrared emittance roofs incur surface temperatures that are only about 3°C (5°F) warmer than the ambient air temperature, while a dark absorptive roof exceeds the ambient air temperature upwards of 40°C (75°F).
In predominantly warm climates, the high solar reflectance and high infrared emittance roof drops the building’s air conditioning load and reduces peak energy demands on the utility. In North American climates, being predominantly cold, a more moderate reflectance and a low emittance result in a warmer exterior roof temperature, which reduces heat loss from the building.
Temperature, heat flow, reflectance, and emittance field data have been catalogued for a full 3 years for 12 different painted and unpainted metal roofs exposed to weathering on an outdoor test facility. Habitat homes were tested unoccupied for a full summer in Ft. Myers, Florida.
Measurements showed that the white reflective roofs reduced cooling energy consumption by 18-26% and peak demand by 28-35%. The houses were side-by-side, and had different roofing systems designed to reduce the
attic heat gain.
Results show that a judicious selection of the roof surface properties of reflectance and emittance represent the most significant energy and cost saving options available to homeowners and builders.
Metal roofing is a proven product, more durable than most available roofing systems. Metal roofs simply last longer, and is often the roofing choice for many government, school and industrial buildings.
Metal roofs rate high in wind, fire, and hail resistance.
Not only will a metal roof keep your house comfortable, regardless of the weather outside, it may actually lower your air conditioning and heating bills.
According to the National Association of Homebuilders Research Center, 20 billion pounds of asphalt shingles are dumped into US landfills every year. The recycled content of the steel in a metal roof is far superior to asphalt. Metal roofs also have a low per unit area weight, making it possible in most cases to install directly over existing roofs, saving removal and disposal costs.
This article is about using fly ash to improve the quality of concrete while reducing its environmental impact. We are all concerned about the quality of Portland cement concrete used in our projects, and I hope also about reducing the environmental impacts of our built environment. There is a way to achieve both of these at the same time by the addition of fly ash to concrete.
Fly ash is a byproduct of the emission controls of coal fired power plants. Most fly ash is landfilled but can be recycled as an ingredient of concrete. It consists basically of tiny spheres of silica and is considered a “pozzolan” additive. Pozzolans are essentially inert fillers that take the place of much more reactive Portland cement and have been used since the Romans learned to make extremely durable concrete 2,000 years ago, even in aggressive marine environments. Portland cement production uses lots of energy and produces massive amounts of carbon dioxide.
Typically Fly Ash is used to replace 10-60% of the Portland cement in concrete. The effect on the concrete is to reduce shrinkage and reduce heat from the hydration of the more active Portland cement. It can lead to a much more durable concrete with less cracking and increased resistance to adverse reactions including Alkali Silica, chloride, and sulfates. It is widely used in highway construction, pre-casting plants, and dam construction. It is less widely used by residential concrete contractors, primarily as a minor hot weather additive to retard setting and reduce cracking, however it can be used in higher amounts and in cooler weather. The key to its successful use is by controlling the water/cement ratio, as are so many other aspects of good concrete.
There is often considerable resistance to fly ash use by trade contractors and even concrete producers. Let’s face it, construction is often very conservative about adopting “new” practices and there is a learning curve to fly ash adoption.
The most common concerns about using Fly Ash is that it will slow concrete setting time and will reduce high early strengths. These can both be addressed with water reducing additives. We can classify water reducers as standard or super plasticizers. Essentially their purpose is to make concrete more workable while using less water. Concrete use is often a conflict between more workability, which make the subs life easier, and a lower water to cement ratio, which does good things for the concrete and makes the engineer happy. Plasticizers can make everyone happier. So how do we use them, how much do they cost, and what is this about a learning curve?
Standard plasticizer is often included with regular concrete mixes, is added during batching at the plant, and shouldn’t have much effect on the cost. Superplasticizer can be added either at the batch plant or at the jobsite, is usually used at 40-90 0unces per yard, and might cost $.10/ounce. This incremental cost increase should be offset by the substituting of inexpensive fly ash for more expensive Portland cement.
Superplasticizer can be thought of as dehydrated water and is useful for other places in residential construction such as making concrete countertops and Portland based tile grouts on floors.
I would recommend learning to use superplasticizer in smaller projects at the jobsite such as sidewalks or driveway sections, before doing a large slab or foundation. The most challenging aspect of its use is probably timing. When used at the batch plant it may lose its effect by the time the concrete is placed. When added at the site it may delay setting time unacceptably. Avoid the temptation to add more water if it sets too soon and instead add more superplasticizer, which is a reason to keep some on the job, even when most of it is added at the plant. If setting is delayed it may be that the plant is adding too much water to improve mix ability and should add “super” early on. Properly used fly ash with super makes for a more workable concrete with higher early and ultimate strengths and improved pump-ability. Since fly ash is a recycled product it can be used to achieve points in LEED rating.
Hopefully this article on fly ash use in concrete will help you make better concrete while reducing its environmental impact.
The answer in all cases is to insure a decent, secure, healthy life for all species on this planet.
As consumers, we are frequently confronted with lifestyle decisions that can impact our environment.
There are choices in this life that can make a big difference in what the quality of life will be for those who follow us.
Going with the flow of our culture is hard to avoid, and unfortunately the flow is not in the right direction for evolving a sustainable future.
One of the most momentous choices that any of us will make is the kind of house we live in.
A sustainable building can be defined as any building that is sited, designed, constructed, operated, and maintained for the health and well-being of the occupants, while minimizing impact on the environment.
Sustainable building practices offer an opportunity to create environmentally sound and resource-efficient buildings by using an integrated approach to design. Sustainable buildings promote resource conservation by including design features, such as: energy efficiency, use of renewable energy, and encouragement of water conservation.
By promoting resource conservation, sustainable building design creates healthy and comfortable environments, reduces operation and maintenance costs, considers environmental impacts of building construction and retrofit, and concentrates on waste minimization.
Sustainable building design also addresses such issues as historical preservation and access to public transportation and other community infrastructure systems. The entire life cycle of the building and its components is considered, as well as economic concerns, environmental impact and over-all performance.
The walls are the largest surface area in a room, yet they are often overlooked in favor of furnishings, accessories, and floor treatments. Walls define the spaces in which we live and work. They play an important role in indoor air quality and are a surface that we naturally look towards as we move through a space. In my experience, once the “right” interior colors are decided upon, there is a sense of self-discovery and emotional well-being for the people living or working in that space. American Clay Enterprises’s Earth Plaster goes a step beyond, offering a product that is both intrinsically beautiful and environmentally sound.
Located in Albuquerque, NM, the American Clay veneer is a blend of pure non-toxic clays that leave out the use of acrylics and cements. This rich textured veneer comes in 12 colors derived from natural non-toxic and ochre mineral pigments and is available in two finishes. Loma offers a richly texture ed Tuscan influence and Porcelina emulates Venetian plaster. The use of clay also plays an important role in controlling indoor environments, making it a great candidate for any climate. It can absorb and then release moisture, which regulates arid and humid air. In bathrooms, this absorption of moisture prevents water from running down the walls. It is mold resistant, and is surprisingly cool to the touch in summer. Winner of the NAHB Outstanding Green Product Award 2004, American Clay Earth Plaster’s commitment to the environment and the future is the beacon of their success.
While the field of green design is still relatively new, finding products that are sustainable without giving up aesthetics is more of a reality in today’s marketplace. Consumers are becoming more educated about issues such as climate change and are beginning to ask questions about their choices on product selection. Technology and values have come together to create interiors that serve our health and well-being while protecting our natural resources for future generations. As people begin to discover that earth plaster and other green products are non-toxic, environmentally friendly, and easy to maintain, there is a realization that one does not need to be considered “green” to recognize the durability and aesthetics intrinsic to many of these new products. Choosing green products for our lives and workspaces is quickly becoming part of who we are today.
Ms. Fox is the principle of Foxline Design, which specialized in green design and freelance writing. She is a member of USGBC and IDS. You may reach her with comments or questions at www.foxlinedesign.com.
LEED (Leadership in Energy and Environmental Design) is a globally recognized sustainability achievement symbol. It is the most widely used green building rating system and is available for new construction and remodels. LEED provides parameters for building efficient, healthy buildings with cost-saving methods.
The benefits of LEED Certification include:
certification requires third party inspection and testing, which provides objective quality assurance above and beyond the mandatory building inspections.
Reduced energy and water usage
Lower operating costs
Less construction waste
More durable buildings
Supports the local economy
Greater resale value
Improved indoor air quality
New Mexico’s Sustainable Building Tax Credit will return up to $13,000 in tax credits for a residential building that earns LEED Platinum Certification.
It is becoming easier for individuals with modest incomes to have their homes remodeled or built to green standards.
Radiant Heating and Cooling can also be called hydronic heating and cooling because it uses water as the heat transfer medium instead of air. It can be called radiant because the majority of heating and cooling transfer in a home is actually through infrared radiation.
To illustrate why it is better to heat or cool with water imagine that you have 2 similar cups in front of you. One of the cups has air at 72 Degrees F and the other cup has water at the same temperature. If you accidentally burn your finger, which cup would you put it into? Correct, the cup with water in it, because water holds 3,500 time as much heat as an equal volume of air. This superior heat holding ability allows much more efficient transfer or storage of heat with water, uses relatively small diameter tubing, and its operation is virtually silent. Heat transfer with air requires 20 times as much power, requires much larger ducts, and is often noisy. A typical hydronic tube has a cross section of less than ½ square inch while a typical forced air duct is 200 square inches. Below is an aerial picture of the hydronic tubing in the floor of a 5,000 square foot building. The heating required in this building is distributed by a pump that uses less than 45 watts!
Radiant (Hydronic) Heating and Cooling System
So what does this mean for the comfort and economy of a building?
In contrast to forced air heating, it is more comfortable, silent, draft free, clean, allows zone controlling of conditioned areas, and is much more energy efficient.
The main disadvantage of radiant heating is that it has usually been assumed that a separate system of ductwork would be required for cooling. With the availability of modern materials and technology this is no longer true. Duct work is not required for cooling but in some climates may be needed for humidity control.
Hydronic Radiant Cooling
We have an amazing new adaptation of a very old technology that is just perfect for cooling buildings in the arid Southwest climate. It provides such superior comfort and performance as to be difficult to describe.
_Up to 80% energy savings
-A greater comfort range.
-Operates in almost total silence.
-No adverse humidity effects.
-Greater Design Freedom.
-Almost no visible components.
-Easy Zone control.
-No Mold concerns.
-Great environmental benefits.
The term for it is hydronic radiant panel cooling, because it uses water instead of air to transport heat and, and it is accurate to call it radiant cooling, because the majority of the heat is removed from the building through radiant transfer from the occupants and other building loads to panels inherent and integral to the building, either the ceiling, walls, or floor.
We are accustomed to using fan forced air almost exclusively in the US for cooling, radiant is much more common in Europe. The Bank of England, built in the 19th century had radiant cooling. Water can carry 3500 times as much heat as an equal volume of air, with the energy cost for transport of heating and cooling 20 times as great in an air system as in a hydronic system.
If you have ever experienced the benefits of radiant heating versus forced air heating, then you have some idea of the difference between radiant cooling versus forced air-cooling. In a large building with conventional air-conditioning, 20% of the occupants are uncomfortable at any one time. You can understand why radiant cooling has become so popular in superior quality construction in Europe.
With radiant cooling you can take free cooling from the desert night skies and store it in the thermal mass of the building, providing dependable, super efficient temperature control. Animals, native to the desert, store the cool of the desert night in their burrows. By taking advantage of the thermal mass inherent in buildings and cooling them between sunset and sunrise we can act like natives instead of fighting entropy and struggling to cool ourselves by pumping heat out of the building at the hottest part of the day. Almost all buildings in the Southwest are built with concrete floors than can be readily used for heat, or cool storage. Thermal mass for cooling works even better than it does for heating, as in solar design, because, while you may sometimes have days without sunshine, you never have nights without darkness.
The total amount of cooling will depend on the dew point outside and the temperature of the water going to the cooler. In some buildings and climates there will be a need for supplemental refrigerative cooling, but the same thermal storage strategy will provide considerable energy savings. The energy costs for the operation of the systems described above is only about 10-30% of that of a conventional refrigeration system and with proper design provides similar energy savings in most climates.
Benefits to the local and global climate are very large. Besides using so much more electricity, refrigerated air conditioning heats and dries the immediate environment. For example, the current summer temperature in Phoenix is 20 degrees higher than it was historically, and most of that change has come about since the introduction of refrigerative air-conditioning to the area. Refrigerative air-conditioning pumps heat from the inside of a building to the outside, plus the waste heat. The fans alone account for about 30% of that waste heat generated. A hydronic system only uses 1/20th as much power for the same function. Compared to a conventional AC system, a hydronic radiant cooling system can save 114 gallons of water, reduce local heating by 683,000 BTU, and reduce carbon dioxide emissions by 338 lbs a day for a typical size house in the Las Cruces area.
In areas that are more favorable, where there is no need for dehumidification or supplemental cooling the payback period is minimal, and the savings impressive, but the most important aspect may be the superior quality of the interior environment.
There are many aspects to building an affordable home. The most obvious is just simply the initial cost. The initial cost is going to be the most obvious factor in the monthly mortgage payments and is the most easily evaluated, but what are some of the other considerations? Let’s look at Location, Design, Execution, Operation, and Resale.
As a real estate agents say, “Location, location, location.” This aspect is going to determine the value of the home and any future improvements. A good location will improve the initial value of the home, the cost effectiveness of future improvements and will determine many other aspects in the livability and long term return on investment (ROI). A higher initial cost for the location can be quickly recouped by the effects it will have on subsequent investments. A poor location will reduce the value of all initial and future expenditures. It can also affect transportation costs, school quality, and insurance costs. The most important effect of a location will be on the eventual equity or resale value.
Design. Construction cost per square foot, maintenance, resale value, and operating costs will be very strongly influenced by design. The trend today is towards ostentatiousness instead of good design. In particular home designs that have lots of exterior corners and exaggerated elevations have an adverse effect. They cost more in every aspect of initial construction and will cost more to operate and maintain. Good design that will retain value involves simplicity and aesthetic choices derived from dividing simple masses into usable areas rather than joining lots of little spaces into a building plan. Initial design is not the place to save costs, but higher design costs don’t insure good design.
Execution. “The devil is in the details” is a motto to live by during construction. There are hundreds of decisions to make during the construction of a house. They will affect how well a home looks, feels, it’s operating and maintenance costs, and even how much cleaning it will require. A common mistake is to expect the builder to make all the right decisions. Another is to expect the building inspector to catch any mistakes. Diligence and legwork by the owners are essential. Independent third party inspection should be considered, such as required by LEED (Leadership in Energy and Environmental Design) Certification. New Mexico has a unique Sustainable Building Tax Credit that will offset the costs of certification, and meeting the requirements of this tax credit will help insure air quality, energy efficiency, durability and other criteria. Certification should also increase resale value. Other tax incentives to consider include Solar Tax Credits and Solar Sales Tax Exemption.
Operation will have recurring costs that should be considered as one of the most important criteria. An obvious example is energy costs. The amount of the home mortgage payments will usually be fixed for a long period while energy costs have risen 4-5% annually for the last 40 years. What was initially considered a reasonable energy cost will increase over the long term while expenditures are in after tax dollars without any return. In contrast, initial expenditures for energy efficiency will appreciate when energy costs go up and also with the increase in building costs, and share the tax advantages of a mortgage. There are energy efficient mortgages that essentially trade a higher initial cost for lower operating costs, allowing more equity to be retained.
Resale should be the uppermost criterion in all home ownership decisions and will be determined by paying attention to all of the above.
A more sustainable building is a better investment for many reasons. It will cost less to own and operate while having better resale value.
New Mexico has a Sustainable Building Tax Credit. This unique and underused credit will return up to $13,000 in tax credits for a residential building that earns Leadership in Energy and Environmental Design (LEED) Platinum Certification. LEED certification requires designing and building to higher standards for several building attributes including Indoor Air Quality, Energy Consumption, Site usage, and Durability. It requires third party inspection and testing which provides an objective quality assurance for the owner, while reducing building operating and maintenance costs and improving a buildings re-sale value.
There is a 26% Federal Residential Renewable Energy Tax Credit (in 2020) that will help pay for solar thermal or solar electric systems and may include the heating system. These systems can be included in the buildings long term financing which is low now and has great tax advantages.
There is an exemption to the Gross Receipts Tax for solar investments.
These tax breaks are money the government provides for you to improve the environment and promote energy independence. They also reduce a buildings operating cost and improve your equity value. A good illustration of this can be made with energy costs. If a conventional building has current annual energy costs of $1,800 a year and energy costs continue to increase 5% annually, by the end of a 20 year mortgage that annual cost will have increased to over $5,000 a year and will have required over $68,000 in energy costs. An important point is that these costs are in after tax dollars and represents money down the drain and a reduced equity position.
In contrast, the investment for energy efficiency can be financed with the tax sheltered mortgage and government subsidies, which results in am improved equity position that will improve with building appreciation and the increase of energy costs.
Additionally, in our experience, our sustainable homes have have re-sold very quickly, even during economic downturns.
Making a positive contribution to the global and local environment with sustainability should be seen as a civic duty. It is important to ourselves and to future generations, and there is no more important place to do that then in the homes we build or modify. A commitment to sustainable building may be the most important decision we can make, and will leave an enduring testimony for the owners.
Sustainability requires making good decisions about many aspects of our built environment. These decisions involve indoor air quality, lighting, comfort, and acoustics. Sustainable buildings have proved to have higher rental values, increased occupancy rates, and improved occupant productivity.
A sustainable building should incorporate timeless superior aesthetics. How can it be enduring if it is unpleasant to look at or live in?