3 Homes Put Energy Ideas to the Test
By Tracy Idell Hamilton – Express-News
Web Posted: 07/14/2010 8:44 CDT
Editor’s note: This story originally appeared Sunday, July 11, exclusively in the print edition of the San Antonio Express-News. View full story on-line.
CPS Energy has taken a peek inside the future of home building — and so far, it likes what it sees.
The utility’s engineers are analyzing energy-use data from dozens of high-tech monitors at three homes with identical floor plans in Northwest San Antonio that were built last year to varying degrees of energy efficiency.
The U.S. Energy Department also is keeping an eye on the comparison as part of its larger effort to encourage cost-effective energy-efficient building technologies.
While the study is a little more than halfway complete, the homes already have yielded information that will benefit local customers. CPS is offering a new rebate for spray-foam insulation, which the study found saved more energy than expected because it seals a home’s “thermal envelope,” unlike fiberglass.
Another key finding: Orienting the solar tiles on the roof of one house to the southwest, rather than the south, resulted in a greater reduction in the home’s peak energy demand.
CPS is keen to reduce power consumption during peak times, such as the early evening, when most people come home, crank up their air conditioners, flip on the television and start cooking dinner. Peak power is the most costly energy a utility produces — a cost it passes on to the consumer.
Those and other findings will be crucial to the utility’s effort to conserve 771 megawatts of power by 2020, a cornerstone of its long-term energy plans.
Those savings would negate the need to build an additional power plant during that time, utility officials say.
To achieve those goals, CPS must understand which efficiency measures are most cost-effective in San Antonio’s climate. The utility will use the data it gathers from the homes to craft incentive packages for builders and homeowners to spur demand and drive up savings.
“CPS considers efficiency the fifth fuel,” after nuclear, natural gas, coal and renewables such as wind and solar, said Bruce Evans, director of customer solutions for the utility. “Reduction of use increases the available supply, so it’s also the cheapest and cleanest form of energy.”
Measuring everything
Buildings use more energy than any other sector of the U.S. economy, according to the Energy Department, consuming more than 70 percent of electricity and more than 50 percent of natural gas. That means they’re also the largest emitter of carbon dioxide, a greenhouse gas most scientists say contributes to global warming.
Making buildings more efficient, according to the Energy Department, results in long-term cost savings for homeowners and businesses, reduces carbon-dioxide emissions and can also reduce peak energy demand.
Under its Mission Verde initiative, San Antonio approved rules last year that requires new homes be 15 percent more efficient than in the past.
The city later adopted the 2009 International Energy Conservation Code, which also requires increased energy-efficient measures. More stringent guidelines are expected under both international and local codes by 2012, and Mission Verde calls for carbon-neutral homes by 2030.
And while there are plenty of computer models that attempt to quantify the energy savings of a particular technology, CPS wanted to see real-world results specific to San Antonio’s climate.
Teaming up with Woodside Homes of South Texas, CPS subsidized the cost of building three homes, each one 2,027 square feet, in the Avalon subdivision off Old Prue Road.
One home was built to Woodside’s usual standards; it is supposed to be 10 percent more efficient than a home built to the building code standard in place at the time. It’s considered the control home.
The second has better insulation, more efficient heating and cooling systems and high-efficiency appliances. The third home has all that, plus a small array of solar roof tiles.
Unlike traditional solar panels, which are obtrusively bolted to a roof, the solar tiles are the same shape and thickness as the concrete tile on the rest of the roof.
The homes were sold, with the owners’ understanding that engineers would monitor their every energy move.
“They’ve been wonderful, very cooperative” about the intrusions, said Valerie von Schramm, senior research manager with CPS’ energy research and technology initiatives department, who’s leading the study.
The homeowners declined to be interviewed for this article.
Multiple meters and other instrumentation send energy-use data on each separate technology to CPS in 15-minute increments, allowing engineers to separate the effects of each.
For example, last month engineers could see the solar home, which has the best insulation, consumed 274 kilowatt hours for air conditioning. By comparison, the control home used almost four times that for its cooling needs.
Von Schramm and her team also learned through testing was that the control home actually was 14 percent more efficient than a home built to code, not 10.
“Woodside builds a tight home,” she said.
The two peak performance homes are even tighter, thanks in large part to the spray foam insulation.
The solar home, which uses spray foam in the walls and attic rather than fiberglass, had 70 percent fewer air changes per hour — used to measure the leak rate of a home — than the control home, while the middle home with some foam and some fiberglass had 40 percent fewer.
The solar tiles, while not enough to power the house entirely, did generate enough electricity to supply about 30 percent of the residents’ needs last month. In the afternoons, the tiles produced more electricity than needed, making the house a net power generator. And because the tiles were facing southwest, they sent energy to the grid later in the afternoon, when demand is peaking.
Researchers from the Florida Solar Energy Center, a research institution affiliated with the University of Central Florida, also are studying the homes as part of the Energy Department’s Building America Industrialized Housing Partnership program, which aims to reduce the energy cost of housing by 30 percent to 70 percent.
Dave Chasar, a senior research engineer with FSEC, says it’s invaluable that CPS has invested in three different homes with different levels of efficiency. Most of the test homes in its program, he said, are stand-alone affairs.
Studying three “with the same weather, the same floor plan, that’s unique,” he said. “We really have a way to compare (different building technologies) very directly.”
At this point, engineers mainly are analyzing how the different technologies impact energy use in each house. They have 10 months of data now, and will keep monitoring for another six months — or longer, if the homeowners agree.
What’s affordable?
The next step for CPS, said Cris Eugster, the utility’s chief sustainability officer, will be to calculate which efforts will give home builders or owners the biggest bang for their buck.
Because the impact of the spray foam insulation was so impressive, he said, the utility wanted to get a rebate program up and running, but it still will crunch the numbers.
“Is it a three-year payback or a 10-year payback? It’s too early to say right now, but if it’s shorter, we want to encourage even more people to do it. (Spray foam insulation) could be a big deal here.”
CPS’ rebate is only for existing homes at this point, as is the federal tax credit available for spray foam. The utility’s website includes a list of approved contractors.
The foam works so well because it effectively cuts off air flow by sealing small cracks in the home. Previously, the utility recommended fiberglass batting of at least a 6-inch thickness, which von Schramm said could be “extremely expensive” — and it still doesn’t cut air flow.
Spray foam works better, she said, “and now we have the data to prove it.”
CPS’ findings are in line with national guidelines.
The Environmental Protection Agency and DOE are updating their Energy Star home requirements, which will have an increased focus on reducing air flow and tightly sealing a home’s thermal envelope.
Making sure those improvements are affordable is a major focus for the federal agencies and CPS, which carefully weighed the costs of the upgrades added to the three test homes.
“We knew we could build a million-dollar home,” and create a “net-zero” house, or one that produces 100 percent of its own power needs, von Schramm said. “We wanted to know, ‘What would it take to build something affordable?’ ”
Still, the utility spent about $68,000 on upgrades, costs which weren’t entirely passed on to the buyers, said Peter Evans, division president of Woodside Homes. About $24,000 of that went for the solar tiles, about $6,000 more than a similar-size system using standard photovoltaic panels.
“It was easy to sell all three homes, but only because CPS subsidized the cost,” he said. For example, the asking price for the solar home was $261,000, but including all the upgrades, it would have cost closer to $300,000.
Evans said he didn’t think, given the economy, that most homebuyers are ready to pay such a premium. But CPS’ research should benefit existing homeowners as well.
The utility plans to spend more than $150 million to weatherize homes for low-income residents in the next decade as part of its efforts to reduce consumption, and it will incorporate the most effective technologies that come out of this study to do so.
But even with all the cutting-edge technology, home energy savings often comes down to personal habits. “Once you get the envelope under control, the rest of the energy use is up to the homeowners,” von Schramm said. “If they want to lower their bills, they can.”
Family size also plays a part. The control and solar homes have similar-size families, while a smaller family lives in the middle home.
So, for example, the solar family consumed more kilowatt hours of power in the month of June than the single person, even with the offset of 345 kilowatts hours generated by the solar tiles.
Water use is similarly affected by family size and habit.
“The solar family is using 14 percent less water,” von Schramm said. “So they will save energy because they use less water and also because their water heater is almost 25 percent more efficient.”
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Spray Foam insulation in the news
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CUSTOMER COMMENTS/FEEDBACK
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Energy Tips
Energy Tip: Do I need more attic insulation?
Most homes in the U.S. do not have enough insulation. An estimated 60% of homes do not meet the level of needed insulation to keep energy bills at their lowest. The odds are stacked against us, since more than half of all homes do not have proper attic insulation.
Here in Maryland we are always looking for ways to help stay cooler and reduce our homes energy costs. One area that could use improvement in many homes, especially older homes in the Maryland area is the attic insulation. Below is a guide to help determine if it would be financially advantageous to upgrade your attic insulation. The R values are estimates, different types of insulation have different R values per inch.
If your home was built before 1979 and the insulation has not been upgraded since then, you could probably save significantly by increasing the amount of insulation in your attic. During this time energy was cheap so insulation wasn’t much of a concern. When I’m doing home inspections in Maryland on homes this age, We typically find between 2 to 4 inches of insulation which is equal to about R-11 depending on the type of insulation installed.
If your home was built between 1979 and 1984 you could probably save moderately on your energy bill by adding insulation in your attic. Typically we find between 5 and 8 inches of insulation in the attic when doing home inspections in Maryland on homes this age, this is equal to approximately R-19 depending on the type of insulation installed.
If your home was built after 1984, your attic insulation probably still does not meets current standards. Adding insulation would probably still save on your energy bill. Typically on homes of this age we see anywhere from 8 to 14 inches of insulation which is from R-30 to R-38.
According to the U.S. Department of Energy, it’s all in the R value. (A number used to measure the resistance of heat flow a material has – the larger the number, the more resistant.) This number should be between 49 and 60 for attic insulation.
Estimated R values per inch for common types of insulation:
- Blown in cellulose R-3 to R-3.8
- Blown in fiberglass R-2.5 to R-3.7
- Fiberglass batts R-3.1 to R-4.3
- Spray foam R-3 to R-7 (depending on type)
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The C&R Advantage
Attention Contractors or Home Builders: We are always striving to partner with homebuilders, “green” building designers, architects, contractors, or inspectors with similar values and professionalism. Feel free to contact us in (443) 219-3626 or INFO@SPRAYED-IN.COM for opportunities if you are in the construction industry.
Advantages of Building Homes with C&R INSULATION,LLC
• Differentiate from your competition
• Improve sales
• Reduced warranty claims
• Happier customers
• More referrals
• Qualify more buyers with Energy Efficient Mortgage
• Can be sold as an upgrade to any home
• Enhanced reputation
• Marketing power of energy efficient building
• Reduced liability
Energy Efficient Homes Sell
Studies by Honeywell listed energy efficiency in the top ten desired features for home buyers.We can help you construct a persuasive marketing program that will enhance your sales and upgrade options.
Builders all over the country are finding that energy efficiency is a great selling tool. It doesn’t make any difference whether you are building starter homes or waterfront masterpieces. Affordable homes need to be built as efficient as possible to keep homeownership in the reach of families just starting out. Large custom homes, built for the most discriminating buyer, need to be very energy efficient because these buyers understand that it makes no sense to waste money on utility costs.ENERGY STAR
Programs such as Energy Star Homes, a program of the U. S. Department of Energy and EPA has tremendous recognition among the public. Linking up with Energy Star will make selling your homes a simple matter. The American Lung Association has their Health Home program that appeals to those with allergies and respiratory problems. Both these programs encourage energy saving features.MOLD & MILDEW
Mold has become a huge concern for builders all over the country. With homeowner’s insurance policies excluding mold coverage, they are going after the builders to pay for remediation of mold problems. A relatively small mold problem can cost nearly $10,000. A serious problem can easily reach into the tens of thousands of dollars. Energy efficient homes help reduce the potential for mold growth. -
2009 Tax Credit Information
On February 17, 2009, President Obama signed a stimulus bill (The American Recovery and Reinvestment Act of 2009) that made some significant changes to the energy efficiency tax credits.
The highlights are:
• The tax credits that were previously effective for 2009 have been extended to 2010 as well.
• The tax credit has been raised from 10% to 30%.
• The tax credits that were for a specific dollar amount (ex $300 for a CAC), have been converted to 30% of the cost
• The maximum credit has been raised from $500 to $1500 for the two years (2009-2010).Home improvement tax credits are available for home improvements “placed in service” from January 1, 2009 through December 31, 2010. Any qualified home improvements made in 2008 are not eligible for the tax credit. The tax credits are available for insulation, replacement windows, non-solar water heaters, and certain high efficiency heating and cooling equipment. Other notes and details about the available tax credits are:
• Maximum amount is $1,500 in 2009 & 2010 for most home improvements
• Must be for taxpayers principal residence
• If you are building a new home, you can qualify for the tax creditHome builders are eligible for a $2,000 tax credit for a new energy efficient home that achieves 50% energy savings for heating and cooling over the 2004 International Energy Conservation Code (IECC) and supplements. At least 1/5 of the energy savings must come from building envelope improvements. This credit also applies to contractors of manufactured homes conforming to Federal Manufactured Home Construction and Safety Standards.
There is also a $1,000 tax credit to the producer of a new manufactured home achieving 30% energy savings for heating and cooling over the 2004 IECC and supplements (at least 1/3 of the savings must come from building envelope improvements), or a manufactured home meeting the requirements established by EPA under the ENERGY STAR program.
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Sick Building Syndrome (SBS)
Sick building syndrome (SBS) is a situation in which occupants of a building experience acute health effects that seem to be linked to time spent in a building, but no specific illness or cause can be identified. The complaints may be localized in a particular room or zone, or may be widespread throughout the building.
Frequently, problems result when a building is operated or maintained in a manner that is inconsistent with its original design or prescribed operating procedures. Sometimes indoor air problems are a result of poor building design or occupant activities.
What Are the Symptoms of SBS?
Building occupants complain of symptoms associated with acute discomfort. These symptoms include headaches; eye, nose, and throat irritation; a dry cough; dry or itchy skin; dizziness and nausea; difficulty in concentrating; fatigue; and sensitivity to odors. With SBS, no clinically defined disease or specific chemical or biological contaminant can be determined as the cause of the symptoms. Most of the complainants feel relief soon after leaving the building.
SBS reduces worker productivity and may also increase absenteeism.
What Causes SBS?
While specific causes of SBS remain unknown, the following have been cited as contributing factors to sick building syndrome. These elements may act in combination or may supplement other complaints such as inadequate temperature, humidity, or lighting.
- Chemical contaminants from outdoor sources: Outdoor air that enters a building can also be a source of indoor pollution. Pollutants from motor vehicle exhausts, plumbing vents, and building exhausts (bathrooms and kitchens) can enter the building through poorly located air intake vents, windows, and other openings. Combustion byproducts can also enter a building from a nearby garage.
- Chemical contaminants from indoor sources: Most indoor air pollution comes from sources inside the building. For example, adhesives, upholstery, carpeting, copy machines, manufactured wood products, cleaning agents and pesticides may emit volatile organic compounds (VOCs) including formaldehyde. Research shows that some VOCs can cause chronic and acute health effects at high concentrations, and some are known carcinogens. Low to moderate levels of multiple VOCs may also produce acute reactions in some individuals. Enviromental tobacco smoke and combustion products from stoves, fireplaces, and unvented space heaters all can put chemical contaminants into the air. It can also come from synthetic fragrances in personal care products or in cleaning and maintenance products.
- Biological contaminants: Biological contaminants include pollen, bacteria, viruses, and molds. These contaminants can breed in stagnant water that has accumulated in humidifiers, drain pans, and ducts, or where water has collected on ceiling tiles, insulation, or carpet. Biological contaminants can cause fever, chills, cough, chest tightness, muscle aches, and allergic reactions. One indoor air bacterium, Legionella, has caused both Pontiac Fever and Legionnaire’s Disease.
- Inadequate ventilation: In the 1970s the oil embargo led building designers to make buildings more airtight, with less outdoor air ventilation, in order to improve energy efficiency. These reduced ventilation rates have been found to be, in many cases, inadequate to maintain the health and comfort of building occupants.
What Are the Solutions to Sick Building Syndrome?
Solutions to SBS problems usually include combinations of the following measures:
- Increasing the ventilation rates and air distribution is often a cost-effective means of reducing indoor pollutant levels. At a minimum, heating, ventilating, and air conditioning (HVAC) systems should be designed to meet ventilation standards in local building codes. Make sure that the system is operated and maintained to ensure that the design ventilation rates are attained. If possible, the HVAC system should be operated to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 62-1989. If there are strong pollutant sources, air may need to be vented directly to the outside. This method is especially recommended to remove pollutants that accumulate in specific areas such as restrooms, copy rooms, and printing facilities.
- Removal or modification of the pollutant source is the most effective approach to solving a known source of an indoor air quality problem when this solution is practicable. Ways to do this include routine maintenance of HVAC systems; replacing water-stained ceiling tiles and carpets; banning smoking or providing a separately ventilated room; venting contaminant source emissions to the outdoors; using and storing paints, solvents, pesticides, and adhesives in closed containers in well-ventilated areas; using those pollutant sources in periods of low or no occupancy; and allowing time for building materials in new or remodeled areas to off-gas pollutants before occupancy.
- Air cleaning has some limitations, but it can be a useful addition to source control and ventilation. Air filters are only effective at removing some, not all, of the pollution.
- Education and communication are important parts of any air quality management program. When everyone associated with the building, from occupants to maintenance, fully understands the issues and communicates with each other they can work more effectively together to prevent and solve problems.
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Spray Foam Comparison
With an understanding of the five insulation decision criteria you are ready to make your own evaluation. If you are only concerned about controlling conductive heat loss, then we would suggest that you look at the lower cost alternatives of fiberglass or cellulose insulation. If the other decision criteria are important to you, then we invite you to continue reading our report. The remainder of the report will show you how the different insulation types compare against each of the five decision criteria. CnR Insulation carries both open and closed-cell spray foam products. The closed-cell product is used for specialty applications such as tight spaces and extra high humidity applications such as indoor pools. The remainder of this report will compare these products against traditional insulation types.Comparing Heat Transfer Control
As you can see in the table below, open-cell foam is about the same as cellulose and fiberglass at controlling conductive heat transfer. Closed-cell foam has about double the ability to control this type of heat loss or gain. You should note that the Dept. of Energy reports that dry cellulose settles up to 20% and fiberglass 2-4% over time, which implies you need to add 20% more cellulose in attic applications ( you cannot do that for wall applications ) . Either type of spray foam will not settle over time. Cellulose can also settle more if it becomes wet and will lose a significant amount of its R-value
The last column of the table shows the air permeability ASTM E283 test results. The numbers show that both open and closed-cell foam all but stops air flow, which makes both products excellent convective insulators. We could not find test results for either cellulose or fiberglass, but a study by Energy Design Update shows open-cell spray foam is the best at stopping air flow.
Product R-Value Perm Value Open-cell Spray Foam 3.8 0.008 Closed-cell Spray Foam 7.0 0.001 Cellulose 3.8 Not Found Fiberglass Batts 3.7 Not Found Comparing Building Safety Measures
As stated in the earlier part of this report, a Class 1 or Class A fire rating is an important decision criteria. The table to the right shows both open and closed-cell foam are meet the class 1 fire rating criteria of a flame spread index of <= 25 and smoke development index of <= 450. Craft paper backed fiberglass insulation does not report these numbers, probably because the paper will catch fire. Cellulose is recycled news paper, which is treated with a flame retardant such as boric acid. It has been reported that the boric acid looses 28% of its effectiveness after two years. Also, boric acid in cellulose has been reported to become corrosive after becoming wet. Additionally, tests conducted by the California Bureau of Home Furnishings and Thermal Insulation have demonstrated that some cellulose samples failed the standard fire safety test only six months after installation.
Comparing Health Measures
The results of the ASTM C1338 standard tests whether the insulation material will support mold growth. Again, both open and closed-cell cellulose do not report any mold/mildew growth. Non-paper backed fiberglass will not support mold/mildew growth. Paper is growth media for both mold and mildew. It is well known that mold/mildew can grow on the commonly installed paper-backed fiberglass insulation. Cellulose is treated with a fungicide chemical, but we could not find any reported ASTM test results. Also, we could not find the specific fungicide that is used or any long-term studies about the health affects of the fungicide on building occupants. Both cellulose and fiberglass are known to have particulate matter that can become airborne.
Comparing Environmental Impact
The largest positive environmental impact that insulation can provide is based on the energy usage reduction. Both types of spray foam insulation can reduce energy utility usage/costs by 50% – 70% in newly constructed homes, as compared to traditionally fiberglass insulated homes.
Conclusion
We hope that you have found the information in this report useful, and we thank for taking the time to read it. We believe our spray foam insulation products provide you with a significant value for your money. Spray foam insulation is a premium building product, because it address several building factors. We hope you agree with us and decide to allow us to help with your building project.
