Green Tips
Energy-Efficient Appliances
Technology Snapshot & Benefits:
Both immediate and indirect economic savings can come from energy-efficient appliances such as refrigerators, horizontal-axis washing machines, clothes dryers, dishwashers, etc. Immediate and continuing savings accrue from lower utility bills for electricity and/or water. The performance levels of these appliances meet, and generally exceed, those of industry standard models. As a case in point, consider household refrigeration. By the late 1970s, refrigerators reached their most inefficient performance by requiring about 1750 kiloWatt-hours per year to operate. Modern energy-efficient refrigerators provide the same or better service at 450-550 kiloWatt-hours per year, and they are much quieter in operation.
Estimated Cost Savings:
The direct economic savings achieved by efficient appliances are a function of how much the appliance will be used, the performance level of the equipment being replaced, and local costs for utilities. When you replace older equipment, it is not uncommon for electricity consumption for that appliance to decrease by 50% or more. In general, if the appliance being replaced is more than 15 years old, and it is replaced with a state-of-the-art unit, you may expect utility savings of 20%-60% compared with the energy required by the previous appliance. Horizontal-axis washing machines typically save consumers 50% in both electric and water utilities. Additional savings come from reduced quantities of detergent.
Your monthly electrical bill is for all electricity used by all electrical loads in the building, so changing a single appliance will lower the bill, but in proportion to the amount of electricity formerly used by that appliance. If refrigeration represents 15-20% of your electric bill, a new refrigerator that is twice as efficient as the unit being replaced will lower your total bill by about 7-10%.
Energy-Efficient Windows
Technology Snapshot & Benefits:
Significant economic savings can come from modern windows. Unless recently upgraded, your windows are likely a major source of heat loss. In cold climates, windows transfer heating energy out of the building through both conduction and radiation. Additionally, depending upon how weather-tight the frame and seals, windows may transfer energy by convection as well. This situation is reversed in hot climates, with windows allowing heat into a building and forcing expensive cooling systems to work overtime.
Typical walls in homes are insulated to a level of R-11 to R-19, yet a single pane of standard glass has an insulating value of about R-1. In other words, heat can leak out of, or into, a building about 11 to 19 times more easily through glass than through the wall. This is why your grandparents insisted on installing storm windows for the winter in northern climates to boost window-insulating value to R-2, or perhaps R-2.5 with a good seal and tightly trapped air between the panes.
Modern windows using specially developed E-glass are much more effective at keeping heat and cold where you want them. Most progressive window manufacturers offer several lines of energy efficient glass with R values in excess of R-4. New designs still in laboratory development promise R-values of 10 or more.
Since glass is a fixed part of the building envelope, it performs 24 hours each and every day. With energy efficient glass, less fuel is required for a given level of comfort with corresponding cost savings and pollution savings.
Estimated Cost Savings:
Assuming the same or greater level of comfort that you are used to, you can save a lot of energy and money by eliminating heat loss or gain through windows. It is common in Northern climates to save 30-40% of annual heating costs with super-efficient windows. With a monthly heating bill of $200 dollars, this equates to an estimated savings of $60-80 per month. Some large homes cost as much as $600 per month to heat, and the savings for these homes could approach $240 per month.
Energy Recovery - Controlled Ventilation Systems
Technology Snapshot & Benefits:
The growing trend toward "tightening the home" improves a home's energy efficiency by controlling air and moisture movement to and from the home. However, making the home "tight" with poor ventilation can cause the home to retain moisture (which may cause mold) and other factors that compromise indoor air quality. Controlled ventilation systems are a means of increasing the amount of cleaner, fresher air entering the home, without the energy losses associated with simply opening windows.
Estimated Cost Savings:
Systems can capture energy in the exiting air and then transfer that energy to the air entering the home. Product manufacturers should be able to provide cost saving estimates for specific properties.
Insulating for Energy Efficiency
Technology Snapshot & Benefits:
You can save a lot of money by installing or improving insulation. Insulation retards the flow of heat and is one of the most cost-effective investments that you can make. The effectiveness of insulation is measured by its tested resistance to heat flow and is known by its R value. The greater the R value, the greater the effectiveness. One of the easiest and most effective places to install insulation is in the attic, since heat rises from the heated rooms below. Insulation comes in many different forms including the familiar fiberglass, Styrofoam, vermiculite, pouring wool, cellulose materials such as shredded newspaper, and numerous foamed-in-place types. Particularly within the fiberglass and rigid foamed board types, there are a variety of choices of heat-reflective coatings. Properly installed insulation always improves comfort and reduces heating and cooling costs.
Estimated Cost Savings:
Heating buildings is one of the largest expenditures of energy in the nation and one of the greatest opportunities for saving. The average U.S. household spent more than $2,350 in 1999 for energy: $1,200 for home energy and $1,150 for motor gasoline to run vehicles. (AEO2001, p.213) Of the $1,200 spent in the home, nearly half is spent for heating and cooling (AEO2001, p.162) and in aggregate, amounted to more than $50 billion in 1999. (p.159)
For new construction, the maximum recommended amounts of insulation yield huge savings compared to no insulation. For existing buildings, upgrading to the recommended amount of insulation will save money. The amount of savings vary widely depending upon your starting point namely, how much insulation you already have. See Energy Star's Cost-Effective Insulation Values for Existing Homes for recommended insulating values for walls, floors, ceilings, and basements.
In general terms, when you double the R value of your insulation, the heat flow through the insulated surface will halve. Your bill, however, may not halve because of other, less well-insulated surfaces in the building. Typical savings for retrofit insulation are on the order of 20-30% of your heating bill. For a monthly heating bill of $200, this can amount to $40-$60 in savings.
Moisture Management for Energy Efficiency and Comfort
Technology Snapshot & Benefits:
You can increase comfort and save money by mindfully managing the moisture content of the air in your home. Humans are most comfortable at a relative humidity of 50%, plus or minus 10%. Relative humidity is the amount of moisture that air contains relative to the maximum amount that it could contain (at any given temperature and pressure). Two separate strategies are required: one for summer and one for winter.
In the winter, air inside the house is cycled repeatedly past heating elements in your heating system, where it gets drier and drier. As room air dries, you will increasingly experience dry and itchy skin, dry eyes and mouth, chapped hands, static electricity and a wide range of other discomforts. From an energy efficiency perspective, the dry air increases the rate of evaporation of body moisture from your skin and this evaporation makes you feel chilled. A normal reaction is to turn up the heat as you attempt to keep warm. The net result is that you will burn extra fuel to maintain a higher room temperature and the air will become progressively drier. In the winter, your strategy is to add moisture to the air.
In summer, the situation is generally reversed and your strategy is to reduce relative humidity of the room air. As humidity levels increase above about 50%, evaporation from your skin is reduced. Lower evaporation rates deprive your body of its normal cooling mechanism and you feel warm. A typical reaction is to turn down the thermostat of your air conditioning in an attempt to keep cool. The net result is that you will burn extra fuel and money to maintain a lower room temperature than necessary, compared to the amount of cooling that is needed if relative humidity is maintained at comfortable levels.
Studies have shown that when humidity is maintained at around 50% in a living space, air conditioner thermostats may be set as much as 5 to 7 degrees (F) warmer while providing the same level of comfort to occupants. Since most air conditioners are electric, and most electricity is produced in central-station power-plants, energy and pollution savings from reduced air conditioning are huge. This is because the electricity that arrives at your electric outlet is produced and delivered at an overall fuel efficiency of about 30%. Turning up the thermostat of your air conditioner has a dramatic and positive effect on your electric bill and on summer pollution levels. To do this and maintain (or improve) comfort, you must control relative humidity of the room air.
Estimated Cost Savings:
Economic savings achieved by moisture control are in direct proportion to how much less you run your furnace in the winter and air conditioner in the summer. Costs to achieve moisture control vary with the level of sophistication of the equipment. At the inexpensive end are simple operational changes that cost you nearly nothing. An example is the practice of venting a clothes dryer through a lint filter to the interior of a building rather than the exterior. This technique captures productively both the moisture in the clothing and the heat generated by the clothes dryer. In addition, a new generation of rechargeable desiccant technologies is emerging that provide low-cost means of reducing moisture in buildings during the summer months. Depending upon the level of sophistication of equipment and controls, you may expect savings to your utility bills in the range of 10-30%.
Natural Daylighting
Technology Snapshot & Benefits:
Both obvious and hidden economic savings come from building designs that rely on natural lighting. Throughout much of the day, owners and occupants can easily benefit from natural lighting and avoid electrical consumption otherwise required by artificial indoor lamps. Not so obviously, considerable economic gain may be achieved through increased productivity of workers and occupants. Studies have repeatedly demonstrated that natural illumination is the gold standard by which the efficacy of artificial lighting technologies is gauged. Further, studies show that workers with access to windows and natural light are happier, more productive, and suffer fewer health problems than workers resigned to artificial lighting.
Technologies include efficient windows, skylights, light shafts, and many architectural features that allow natural light to penetrate into the building. Newer technologies are used as well. Over the past decade, some Japanese shoppers have benefited from natural light delivered to the interior of shopping malls via fiber optic cables originating on the roof.
Estimated Cost Savings:
The direct economic savings achieved by daylighting must be balanced against any potential heat loss associated with any window or skylight. For maximum cost effectiveness, only the most efficient windows and skylights should be considered.
Actual savings will depend upon how much you rely on artificial lighting, your local climatic conditions, etc. It is a good idea to check with local builders and energy offices to better calculate energy savings. However, it is unlikely that any consultant will be able to quantify the true value of access to daylight as measured by satisfaction with the building, increased productivity, and improved health.
Heating - Passive Solar
Technology Snapshot & Benefits:
Easy economic savings accrue from designing and building features that effectively trap heat from the sun during the day and release that heat slowly throughout the nighttime. The effect is similar to living near a large body of water where the thermal mass of the water lessens temperature extremes. That means reduced heating and cooling load for a building, and that saves you money.
You may easily incorporate thermal mass into a building for passive solar heating by using materials such as concrete, stone floor slabs, or masonry partitions that hold, then slowly release heat. Orienting your building so that the longest walls run from east to west, and using large south-facing windows, allows the sun to help heat the home in winter. Properly designed roof overhangs shield the building interior from the summer sun. Passive solar designs use natural methods to stabilize the internal temperature of a building without the need for active mechanical devices such as pumps or fans, although these may be used to supplement performance. Passive solar designs also include natural ventilation for cooling. An obvious method is simply locating windows in the building strategically so that when opened, a natural breeze may be easily accelerated in the interior. Openings and passages designed into ceilings will promote the escape of hot air from the interior of the building through the roof or upper windows.
Estimated Cost Savings:
Passive solar designs can reduce heating bills as much as 50 percent. For a monthly heating bill of $200 dollars, you may expect savings of $80-$120 per month. If passive solar features are included at the time of initial construction, or as part of an overall remodeling effort, the effective net cost of improvements will be much lower. However, you will benefit immediately in your monthly cash-flow.
Solar Electricity - Photovoltaics
Technology Snapshot & Benefits:
Photovoltaics are technologies that convert radiant light energy to electricity. Photovoltaic (PV) cells, also called solar cells, are the building blocks of this technology. PV cells are connected together to form larger modules. A module is typically placed near or on a home or building to provide a portion of, and in some cases all of, the building's power and in turn electricity. PV systems are used for "off-the-grid" applications (homes, cabins, and water pumping on farms) as well as federal government applications (traffic warning lights and emergency call boxes near highways).
Estimated Cost Savings:
Cost savings for PV systems are typically calculated in terms of other energy options such as extending power lines or alternative energy systems. Stand-alone photovoltaic systems can be more cost-effective than extending power lines for locations as near as a quarter mile off the grid. On a 20-year, life-cycle-cost basis, a remote PV system typically costs from 25 - 50 cents per kilowatt-hour.
Heating - Central Location for Heating Unit
Technology Snapshot & Benefits:
Combustion units for heating buildings may often be advantageously located centrally within the floor plan of the building. Such placement offers extra radiant heat recovery from a furnace or boiler proper and most importantly from the entire length of the chimney as it progresses upward throughout the house. A centrally located chimney typically provides better draw, since the chimney walls are not chilled by outside temperatures. This design is easy to accomplish in new construction, and a bit more challenging, but still possible, in existing structures.
Estimated Cost Savings:
Cold chimney walls inhibit the upward flow of exhaust gases. In practice, this retarding effect is often overcome by furnace adjustments that send more heat up the flue with an attendant loss in fuel, economic and environmental efficiency. Locating a furnace or boiler centrally in the building may yield savings on the order of 5-10%. For a monthly heating bill of $200 dollars, this equates to an estimated savings of $10-20 per month. For a new building, centrally locating the heating unit may incur no (or very low) additional costs, yet the savings will be permanent. For an existing structure, moving a heating unit to a central location is most cost-effective when the old unit reaches the end of its useful life and it is time for replacement. If these alterations cost $1,000, an improvement of this nature pays for itself over 9-10 years. At the same time, monthly cash-flow improves immediately.
Water Heating - Instantaneous Water Heaters
Technology Snapshot & Benefits:
Easy economic savings can accrue from instantaneous or the on-demand type of water heaters. In contrast to the traditional method of keeping 40 to 80 gallons of hot water at-the-ready in an insulated tank, on-demand heaters produce hot water only when it is needed. Since hot water is generally required for less than a few hours each day instead of 24, owners and occupants can easily benefit from high efficiency modern designs that provide hot water on demand. Less fuel is required for a given volume and temperature of water, with corresponding cost savings and pollution savings. Some manufacturers claim 50% savings when compared to conventional hot water tanks.
Estimated Cost Savings:
Assuming that you consume the same amount of hot water at the same temperature as before, you can save a lot of energy and money by eliminating the slow leakage of heat from the hot water tank and piping. Actual savings will depend upon how much water you use, how far it must be piped from your existing heater, and the extent to which that piping travels through unheated spaces. It is reasonable to expect improvements in your hot water bill of 20 cents on the dollar. For a monthly water-heating cost of $50 dollars, you may expect savings of $10 per month on your energy bill. If the switch to on-demand water heating is made when your old hot water tank conks out, the effective net cost of change will be much lower and your monthly cash-flow will improve immediately.
Building Materials
Technology Snapshot & Benefits:
You can save a lot of money and avoid future headaches by choosing and installing building materials that are safe and appropriate. There is no specific cookbook path to success with building materials. However, your decisions may be usefully guided by asking the following questions:
How well do the alternatives stack up in terms of performance? How well do they do the job for which they are intended? [Recall the sort of discussion found in the roofing industry about sheathing materials the lower cost of particle-board vs. the superior nail-holding ability of more costly plywood]
What unexpected result might occur from each alternative building material? Consider safety issues such as off-gassing of glues from composite building materials and potential radon-emissions of some rock- or earth-based materials.
What toxic effects might be associated with each alternative? Remember that lead in paint was great as an inhibitor of mildew (before its use was banned), but also that lead is linked with blood and bone cancers and other maladies and that a primary exposure pathway to humans was via lead in paint.
What waste streams are associated with the manufacture of alternative building materials?
How recyclable will the material be at the end of its useful life? For example, steel or tin (terne) roofing may be easily recycled into other uses, while asphalt shingles are usually landfilled because recycling is difficult.
To the maximum extent possible, you should think through design options and be mindful of potential consequences (both good and bad) of the choices that you make with building materials.
Estimated Cost Savings:
The framework that you use to evaluate costs and benefits is very important. Generally, the building trades focus on initial cost, but increasingly groups (like the American Institute of Architects) promote broader and more systematic thinking about true life-cycle costs and benefits.
For new construction, your architect or builder may have information that will be useful to you. In fact, you will be able to tell a lot about a builder by how he or she responds to questions like those presented above. For existing buildings, you may be much more in control over the choice of building materials.
Bamboo Flooring
Technology Snapshot & Benefits:
Bamboo flooring is a cost-effective and environmentally sensitive choice among traditional hardwood flooring options. An appealing building material, it is very durable, strong and long-lasting. Bamboo, a grass product and not a wood product, is harvested every 5 years without damaging the actual bamboo plant, and does not require pesticides due to its hardiness. It comes in four different types of flooring: natural, carbonized, vertical, and horizontal graining. The United States Green Building Council's LEED program recognizes bamboo flooring as a green building material and permits points for the use of this flooring.
Estimated Cost Savings:
The pricing of bamboo flooring is comparable to the pricing of hardwood flooring.
Roofs - Durable, Lasting Roofing Materials
Technology Snapshot & Benefits:
Slate, clay, concrete, and composite shingles, as well as metal roofing, offer longevity advantages over common asphalt-based shingles. Properly maintained, roofs made of slate, clay or composite shingles can easily last a century. Metal roofs in traditional standing seam or batten seam applications are available in terne (a thin mixture of tin and lead coating a carbon steel core panel) and now in terne-coated-stainless ( TCS, the same mixture covering a stainless steel core panel). Well-suited to cathedrals and institutional buildings, one manufacturer estimates a useful life of TCS roofing material to be about 500 years. All non-asphalt options provide freedom from reliance upon imported petroleum products.
Estimated Cost Savings:
Installed costs are nearly always greater than short-lifetime asphalt shingles. However, over the lifetime of the lasting roofing material, costs are usually lower than short-life alternatives. Over the span of a century, building owners may expect 4 to 5 roof replacements of asphalt shingles. The attendant labor and landfill costs are often several times that of a long-lasting roofing material. Also, landfill costs are expected to increase. For the homeowner who typically moves every five years, the real value of this measure is in its ability to increase resale value.
Low VOC Paint
Snapshot & Benefits:
Because low- or no-VOC "volatile organic compound" paints have a lower odor and less impact on air quality than higher VOC-content paints, they are excellent for use in buildings where it is desirable to maintain good indoor air quality, such as hospitals, schools, homes and workplaces.
Recent EPA studies estimate indoor air quality to be 3 to 5 times more toxic than outdoor air largely caused by toxic emissions of paints and finishes. Paint manufacturers realized the need to develop paint that contains lower VOC yet maintain high levels of performance and durability ultimately causing less of an impact on air quality then the higher VOC paints.
The use of low-VOC paint reduces toxins that cause allergy and chemical sensitivities, reduces contaminant concentrations in landfill, groundwater and the ozone, provides easy cleanup with soap and water and produces lower odor. With increased legislation and support from environmentally conscious organizations such as the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) and Green Seal plus advances in paint technology the paint industry has come a long way in developing an array of environmentally responsible products with higher performance levels. New paints have become more durable, cost-effective and less harmful to humans and the environment.
Estimated Cost Savings
Low- and no-VOC paints typically cost about the same as a manufacturer's premium line of paints (around $30 per gallon) however, it is important to remember that high-performance paint typically will cost more in the beginning but in the long run "could be the difference between painting once and painting 4 to 5 times in 20 years."
Consider paying the extra cost of buying a high-performance, low-VOC paint as you may not have to apply more than one coat to the surface area greatly reducing your time and overall expense.
"Choosing non-toxic, low-VOC paints in office buildings, schools and hospitals has helped maintain normal productivity within these environments which would be entirely impractical for the occupants to vacate even for short periods of time during a painting project."
Landscaping Shade Trees and Windbreaks
Technology Snapshot & Benefits:
Perhaps the most pleasant economic savings can be derived from judicious and mindful planting of trees and shrubs. The value of traditional plantings serving as windbreaks is well known. Additionally, well-placed deciduous trees can shade a building during hot summer months yet allow warming sunshine to enter a building when warmth is needed in the winter. The summer shading feature of trees is particularly important for the following reason. Most homes are cooled with traditional window- or central- air conditioners using fractional horsepower single-phase electric motors and modern refrigerants (chlorofluorocarbons that are less potent greenhouse gases than their predecessors). The electro-mechanical efficiency of air conditioner components ranges from 35-50% based upon the electrical energy available at the plug. But that electricity is arriving at your building with an overall efficiency of about 30% based upon the energy content of the fuel going into the central electrical power plant. So, when the overall fuel cycle is considered, building air conditioning is about 10-20% efficient, on the basis of energy flow. Fortunately, humans feel a cooling effect from simple air movement that increases evaporation from the skin. Most air conditioning rating systems incorporate this cooling effect, so their efficiency numbers do not appear quite so grim. However, when shade trees cool a house such that one unit of air conditioning energy is avoided, 5 to 10 units of primary energy are avoided at the power plant. This is not only an important economic savings to you, but also a very important environmental savings to the community.
Estimated Cost Savings:
Air conditioning in buildings represents 13-15% of your annual electricity budget, and a larger fraction during summer months. By reducing the amount of air conditioning required, shade trees directly affect your bottom line. The cost of quality shade trees ranges from a few dollars for a seedling to several hundred for a much larger tree. It's a good idea to get at least an 8-10 foot high tree if possible. The sooner the tree grows shading capacity, the sooner you can enjoy savings. The amount of savings can vary widely due to local circumstances but typical savings are on the order of 10-20% of a summer electric bill. Similar savings from a windbreak will be realized in winter during the heating season.
House as a System
Technology Snapshot & Benefits:
When building new energy-efficient houses or making existing houses more efficient significant energy gains can be realized, just by treating the House as a System. You cannot make changes to one part of a house without affecting the many other parts that make up the house system. The house system is made up of the building envelope (foundation, walls, ceiling), the heating and cooling system, the water heating system, the lighting system, the appliances, and a fireplace if present.
Estimated Cost Savings:
Making the home as tight as possible has an incredible impact on your heating and cooling bills.
Information provided by Ecobroker