Green Insight & News

So What Can I do To Conserve Water?
Energy Efficient Home Considerations
Lifestyle: Can I Really Make a Difference?
What Type Of Windows Do I Need?

So What Can I Do To Conserve Water?
Given the current relative affordability of water in eastern North Carolina, it is difficult to justify allocating a portion of your construction budget towards water conservation. However, if we examine trends from around the country, we find a different condition. Severe droughts in some regions of the country have forced water rationing and large price increases. An article published in USA Today notes that the Environmental Protection Agency (EPA) estimates “that the nation’s water and wastewater systems need an investment of up to $1.2 trillion over 20 years.” The article further states that “some communities are getting scalded by price hikes of 50%, 100% or more.” In another article published on the Global Water Intelligence website, the EPA is quotes as saying it “considers water affordable if it does not cause water bills to exceed 2.5% of median household income.” A household income of $45,000 would make a $1,125 annual water bill “affordable.” With these issues looming in other parts of the country, can we be far behind?

Of course, the answer is no. As time marches on, we can expect our water and sewer bills in eastern North Carolina to take an ever-increasing bite out of our income. Therefore, it does make sense to develop a water conservation plan and to allocate a portion of our budget to this concern.

So what can we do to impact our water consumption and get a handle on those water bills? We must take each home water end use and determine how we can reduce usage in that area. For starters, installing low flow water heads on all showers and faucets and using dual flush toilets can begin to help saving on costs. Next, be smart consumers when purchasing appliances that use water by purchasing only Energy Star approved washing machines and dishwashers. Planning plumbing runs can also save water usage. For example, by using instantaneous water heaters and placing them close to the source, the need to wait for hot water to reach the shower or faucet will be lessened.

Outside the home, drought tolerant plantings will require less water to thrive, and drip irrigation systems are available for plantings that do require regular watering. If allowed by property owners associations, rain barrels can be installed at gutter downspouts to collect rainwater to later use in irrigation.

There are many more strategies that can be used to help conserve water in our homes. The ideas listed above can be implemented very easily and at a nominal expense. Once installed, they will integrate into most lifestyles with little notice of implementation. When compared to a comparable home built to code, you can obtain substantial savings with little increased investment.

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Energy Efficient Home Considerations
The most important thing for the builder to implement is cost-effective energy efficiency measures before considering any active solar systems. Solar systems cannot bridge the gap between a moderately efficient home and a zero energy home. Envelopes must be well insulated, lighting and appliances must be very efficient, and HVAC distribution energy must be minimized. Resident behavior must also be addressed. Today’s consumption patterns of Americans are not compatible with the operation of a zero energy home (also see “Lifestyle: Can I Really Make a Difference?”).

The first step to any high performance, energy efficient home is to make sure the building’s thermal envelope is tightly sealed. A building’s thermal envelope is defined as “what separates the building’s conditioned space from the unconditioned space.” The elements of this envelope are the roof/ceiling assembly, exterior walls, below grade walls, windows and doors, the floor assembly (where the floor is over unconditioned space) and the slab edge. This envelope needs to prevent airflow, as well as heat flow and moisture flow. This is accomplished through the use of air barriers, thermal barriers and moisture management strategies. There are many different building systems that will achieve these objectives. Strategies should be discussed with the builder to see which system best meets your needs.

A home with a tightly sealed building envelope will need to address proper ventilation. An airtight home can cause the accumulation of indoor air pollutants. Indoor Air Quality (IAQ) should be an important concern for everyone; however, if you have asthma or allergies, the IAQ in your home could become a quality of life consideration. A good source for information is the EPA site. Pollutants in homes come from many sources-some obvious and some not so obvious. The obvious sources are combustion sources such as cooking, tobacco products and the burning of oil, gas, kerosene, coal or wood. The not-so-obvious sources might be from “off gassing” of Volatile Organic Compounds (VOC’s) from materials we have in our home. VOC’s are chemicals that become a gas at room temperature. Formaldehyde is the more common chemical off gassed in our homes. It is used in thousands of products as an adhesive, bonding agent and solvent, and can be found in furniture, paint, paneling, pressed wood products particleboard and plywood. Limiting of the source of these VOC’s can be achieved by choosing low or no VOC materials in the construction of a home. Meanwhile, controlled ventilation can remove the accumulation of VOC’s from indoor air. Some of the methods of removing these VOC’s pollutants include natural ventilation and mechanical ventilation using Energy Recovery Ventilators (ERV’s), range vents and bathroom vents.

Once the building envelope is sealed and the IAQ has been adequately dealt with, the many different energy end uses impacting our overall energy efficiency can be addressed. The graph shown, published by the U.S. Department of Energy, shows home energy use broken down by category.

Concentrate on the top end use categories allows you to get the biggest bang for your buck. Space Heating (32%), Water Heating (15%) and Cooling (10%) together account for 57% of all home energy consumption. Reductions in any of these areas can have significant effects on energy bills. A cost benefit analysis should be considered to determine the appropriate systems.

The final step in this process is to try and tweak the smaller energy drains in your home such as the appliances and lighting. When choosing appliances, you should always look at the appliance’s “Energy Guide” sticker. Check out the Federal Trade Commission link for help. Where possible, you should use Energy Star rated appliances. For a list of qualified appliances check out this link to Energy Star listings.

Lighting at 6% of energy use can be an easy area to target for savings. Again, the use of Energy Star rated fixtures along with using compact fluorescent light (CFL) bulbs, while a little more expensive, can save you about $30 over its lifetime and pay for itself in about six months. CFL bulbs use about 75% less energy and last about 10 times longer than an incandescent bulb.

The main point of this article is the idea of a “Systems” approach to building. To get the most from a new home, it must be considered a system. Each element contributes to and affects all the others, so consideration must be given to the whole house when making individual decisions on what products to put in your home. Also, a cost/benefit analysis should be assessed for each product to help make a sensible and smart choice. Current and future energy costs as well as initial product cost and maintenance costs should all be part of this analysis. Just remember, the more information you have, the more energy savvy you can become, and the more you will save on your energy costs. After all this planning and work, you will be ready to consider alternative renewable sources of energy such as solar or wind to help reduce your dependency on grid-provided electricity, natural gas and propane.


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Lifestyle: Can I Really Make a Difference?
Can the habits you follow and the way you interact with our home really make a difference in our energy consumption? The answer is a resounding yes. Becoming more aware of your energy usage is the first step in becoming more energy efficient. All the new technology and developments in energy efficient homes cannot be effectively maximized without a full understanding of how these systems work, as well as their limitations. The buzzword in energy efficient housing is a “net zero” home. This is a home that has reduced its energy consumption and increased its energy production to a point where they net out to zero. In some cases, homes are producing more energy than they are consuming and are able to sell this excess energy to the power company.

None of this can be accomplished without changes in your lifestyle. If you are using a solar hot water heater, in order to get the full benefit, you have to adjust the way you use hot water. The sun heats your water during the day, so rather than taking showers early in the mornings, before the sun rises, you may need to shower in the evening, after the sun has had all day to warm the water. Even little things can have a big impact when the effects are added together. Things such as turning off the lights when you leave a room, unplugging electronics chargers and computers when not in use and using a programmable thermostat to control the heat and A/C when you are not at home can save big bucks over the course of a year.

With all the changes being legislated in our government today, it’s important to become more energy literate in order to understand how these changes will affect the way you live. All aspects of our lives that affect our carbon footprint will be increasingly challenged in the future. Becoming more energy efficient and living a more “green” lifestyle has always been the right thing to do. Signs of the future indicate that a failure to do the right thing may come with a punitive cost. Energy is becoming more and more expensive and taking a larger bite out of household budgets. Small adjustments in daily routines can, in fact, have significant affects on the amount of energy consumed.

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What Type of Windows Do I Need?
Did you ever wonder just what all those different numbers on the sticker plastered on new windows mean?

The NFRC (National Fenestration Rating Council) Label:


What do these Energy Performance Ratings mean?

U-factor - Is a measure of the insulating value. U-factor is the nonsolar heat flow through all parts of the window (glass, frame, and sash). The lower this number is the better the insulating value and the greater the performance. It can be thought of as the rate of conduction; the lower the U-factor, the less heat will flow through the window. This number ranges from 0.14 for a super-insulated window to 0.50 for a basic window. It is the reciprocal of an R-value, which measures resistance, so higher numbers are more desirable.

Solar Heat Gain Coefficient - This is the percentage of the sun’s solar heat that passes through the window. Higher numbers mean more passive solar heating potential. This number ranges from 0 to 1.

Visible Transmittance - This is a measure of the amount of visible light that passes through the window. Values range from 0 to 1 (a higher number equals more light). Most ratings are between 0.3 and 0.8 because they take into account the light blocked by the frame. The higher the number maximizes daylight and views.

Condensation Resistance - This is a relative scale from 0 to 100 based on the window’s properties. It predicts the likelihood of condensation, with higher numbers indicating less condensation.

Air Leakage (U.S./I-P) - This is a measure of the amount of air passing through the window assembly; a source of heat gain and loss. This optional rating is expressed in cubic feet per minute through a square foot of window. Look for ratings under 0.3; lower is better.

Overview:
We go through great time and expense to seal all gaps and holes in our homes to create a continuous thermal barrier. Then we cut multiple large holes in this envelope and fill these holes with the worst possible material: glass. A single pane of glass is a horrible insulator. This is why windows used in new construction today are either double or triple glazed. Glazing refers to glass. A single pane of glass has a U-factor of 1.04. By doubling the glazing the U-factor improves to 0.5 and a third glazing improves the U-factor to 0.3. When an additional layer of glazing is added, air space is also created. This air space is used to boost the windows U-factor by replacing the air with gas. Manufacturers use argon or krypton gases because they are inert-chemically stable and non-reactive-and because they reduce heat loss, as they are less conductive than air. Krypton performs slightly better than argon, but its bigger advantage is that the optimal spacing between krypton-filled panes is narrower than what’s required for argon. This is most important when dealing with triple-pane windows.

Manufacturers can also use a coating on the glass to either reflect heat back into the room to conserve it or filter sunlight to keep heat out. Known as a low-e (for low emissivity) coating, it’s common today, even on low-cost windows. By using a coating on two different glass panes, the amount of heat that’s retained in each direction can be fine-tuned. The measure of how much of the suns heat a window allows through is the solar heat gain coefficient (SHGC). This number ranges between 0 and 1 where 1 is uninterrupted heat gain. As the SHGC is minimized, the U-factor declines.

To further increase the insulating value, some manufacturers will add suspended films in the air spaces between the glass. These films are so thin and lightweight, as many as three films can be suspended between two glass panes. Some manufacturers claim an U-factor of 0.09 or a R11.1. This window has the insulating value that approaches that of some wall insulations.

Another major “green” function of a window is known as day lighting, which is a window placement strategy that tries to maximize natural light, and which saves energy by reducing the need for electric lighting. The visible transmittance (VT) rating allows you to compare the amount of light that passes through the windows, taking into account the light blocked by frames and grills.

Finally, tempered glass, or safety glass, is a type of glass required by building code to be used in any location were there is a high potential for breakage. A specific application might be behind a garden tub in the bathroom or next to a swinging door.

For more information on North Carolina specific considerations, visit the Efficient Windows fact sheet guide and view the Energy Star guidelines for our area.

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