Helpful Tips and General Guide to Buying an Energy Efficient Water Heater Read more
Do attic fans lower the cost of cooling your home?
Are solar attic fans worth installing? Common sense suggests they would be but are powered attic fans really a good idea for energy efficiency based on research and science? I have a master’s of science degree and my initial belief was it made sense. It just seems logical that a cooler attic would lower the cost of cooling the house in summer. While researching radiant barriers for the attic and reflective paint (Kool Seal Premium White) for our metal roof, I came across a few articles strongly suggesting powered attic fans were a dumb, and possibly dangerous, idea based on science. Here’s what I found so far and why I removed my attic fan:
- The Scientific Spin on PAVs (powered attic ventilators – fans): Cooling off hot attics with powered attic ventilators (PAVs) seems like a good idea. After all, doesn’t cooler attic air mean less work for the HVAC system, longer shingle life, and reduced energy costs? Unfortunately that’s more myth than fact.
- Drawbacks Of Powered Attic Ventilators:Powered attic ventilators, already suspected of using more energy than they save, can also create excess moisture, structural problems, discomfort, and combustion safety problems for home occupants, according to a recent study. John Tooley of Natural Florida Retrofit, and Bruce Davis of Alternative Energy Corporation’s Applied Building Science Center in North Carolina, presented “The Unplanned Impacts on Houses by Powered Attic Ventilators” at the 1995 meeting of the Energy Efficient Building Association.The paper describes research conducted on eight homes over a period of three months. As a result of this research, Davis said that he wouldn’t recommend the use of powered attic ventilators. He emphasized, “If someone chooses to use a powered attic ventilation strategy, they need to do additional performance tests and take responsibility to be sure that it won’t cause other problems.” The potential for hazardous conditions is particularly high in homes with combustion gas appliances, because the ventilators can create negative pressures that cause backdrafting.
- Energy Star: Attic Fan Ventilation – Attic fans are intended to cool hot attics by drawing in cooler outside air from attic vents (soffit and gable) and pushing hot air to the outside. However, if your attic has blocked soffit vents and is not well-sealed from the rest of the house, attic fans will suck cool conditioned air up out of the house and into the attic. This will use more energy and make your air conditioner work harder, which will increase your summer utility bill.
- Ask the Builder: Powered Attic Fans – Attic Insulation Facts: “I used to recommend PAVs [powered attic ventilators – fans] for houses, but I don’t anymore.”
- Building Science, Unvented Roof Summary Article
The best solution appears to be making sure your attic is well insulated and well-ventilated using passive vents and natural air flow. Inspect your attic insulation and ventilation, or have a contractor do so for you. Just add more insulation or natural (passive) ventilation, if needed. Both measures will reduce the cost of cooling and heating your home; no electricity required and they are perfectly quiet.
ADDITIONAL ENERGY EFFICIENCY RESOURCES
- Contact the local power company website and local energy associations for more information on constructing an energy efficient home in your area.
- Building Science Corporation, Unvented Roof Summary Article: Excellent resource with in-depth research and hard-core science. Building Science is dedicated to teaching and providing factual information concerning building science and energy efficiency. This resource is used extensively by builders “in the know” when it comes to energy efficiency.
- Building Science Guides and Manuals: Good place to start if you want reference documents for some of the most important building science topics.
- Building Science Information Sheets: Fact sheets and overviews; another great place to start for those relatively new to the field.
- Energy Star : The Energy Star website has extensive information on energy efficiency.
- Geothermal Heat Pump Consortium: Geothermal is the most energy efficient method known today for heating and cooling. However, you will benefit by first making sure your home or building is insulated properly and as air tight as possible (within the limits of the appropriate building codes and safety concerns) before considering an expensive geothermal system.
ENERGY EFFICIENCY PRODUCTS
Whether or not you are using an attic fan and you own a fireplace, a great product to consider is a fireplace plug. Battic Door sells several energy conservation products including a simple fireplace plug; stops drafts and saves energy by sealing the chimney when not in use:
The Fireplace Draft Stopper is an inflatable urethane chimney plug balloon pillow measuring 38″ x 16″. A round Fireplace Plug is also available. It is quickly and easily installed in the fireplace just below the damper level. The Fireplace Plug can be adapted to work in almost all fireplaces. Even if you have an unusual construction, the Fireplace Plug can be successfully installed in less than 2 minutes.
The Fireplace Plug is provided with 5 “slittable” areas that can be cut to provide an opening for a damper handle. As the Draftstopper is inflated it seals around the damper handle sealing the opening (helps reduce energy costs). Easy, quick and clean installation.
My metal roof was red, hot, and desperately needed painting. After spending some time inspecting the roof, I quickly realized how incredibly hot the red paint became even on a modestly hot spring afternoon. Why repaint the roof red since it gets so hot? I thought there must be a better solution so I started investigating roof paints. Fortunately, I wasn’t the only one wondering if a lighter-color roof would reduce heat gain inside the attic and save energy. Also, I quickly learned a lot about “reflective” paints, radiant heat, and the best ways to insulate the attic to reduce cooling and heating costs.
One research article I found informative and one I recommend reading is, Cool Roofs For Hot Climates by Dan Parker, a senior research scientist with the Florida Solar Energy Center (2003). The following is from the article:
Reflective roofs work because they stop the rooftop heat before it ever gets going. The sun’s rays hit the roof at the speed of light, and at the speed of light they bounce back into space. White or light-colored materials work best, but some new dark pigments reflect enough invisible infrared radiation to reject a lot of solar energy. And whether you’re applying tile, metal, membranes, or even asphalt shingles, choosing a more reflective version seldom adds cost.
The figure below graphically depicts the best solution for energy efficiency is a reflective white metal roof:
After reading this article and numerous others, I painted my metal roof with Kool Seal® Premium White Elastomeric Roof Coating which I purchased at the local hardware store (ACE Hardward has it here in Richmond, VA).
Additional Metal Roof Information
Roof Costs and Energy Savings: According to the Metal Roofing Alliance, white-painted metal roofing has the highest solar reflectance value of any roofing product available and can save you up to 40% of your annual energy bills.
According to statistics from McGraw-Hill Construction Research and Analytics®, the number of homes with metal roofs has more than tripled over the past decade, moving metal from 3% of the overall U.S. market to 10%.
Some homeowners’ insurance programs allow discounts for homeowners with specific weather-resistant metal roofing products. Contact your insurance agent to determine if your home qualifies.
Photo taken after the 1991 Oakland, California firestorm. Burning embers destroyed all of the homes in the neighborhood, except the masonry home that was roofed with Stone-Coated Steel Roofing. While all of the neighbors fought (without success) to save their homes by watering down their asphalt roofs, burning embers did not ignite the steel roof. The house with the steel roof survived while all others around it were destroyed. (SOURCE: Metal Roofing Alliance: Lower Your Insurance with Weather-Resistant Metal Roofing)
Kool Seal® Premium White Elastomeric Roof Coating
FEATURES AND BENEFITS
(SOURCE: Provided by the manufacturer, see product description, surface prep, etc. here – PDF)
- Energy saving up to 35%
- Reflects 90%+ of the sun’s rays
- Designed to be durable in any climate
- Higher solids for better coverage
- Forms a thick rubber-like blanket of protection
- Expands and contracts – clings to your roof in all temperatures
- Protects against moisture
- Cured elastomeric film is mildew and algae resistant
- Helps to absorb sound
- Environmentally compliant
- Soap and water cleanup – while wet
Energy Efficient Roofing Video by Tod Miller
Other Useful Articles Pertaining to White Roofs:
- Metal Roof Retrofit on a Hurricane Damaged Home by: Dave Chasar, PE. A before/after energy comparison of shingle roof verses white metal roof replacement; includes monitored data collected at the home over several years.
- Metal Roofing Alliance – www.metalroofing.com
- The Cool Metal Roofing Coalition – www.CoolMetalRoofing.com
- Energy Star – www.EnergyStar.com
CPV systems are poised for significant growth thanks to the confluence of several factors: Renewable Portfolio Standards (RPS) requiring up to 33% renewables by 2020 in key US states, higher efficiency CPV systems, and lower CPV system costs. In the last year alone, over 300 MW of CPV projects have signed contracts with utilities and are now awaiting regulatory approvals and financing.
Thanks to these large projects, CPV technology companies may be approaching the critical mass needed to cost-effectively manufacture their systems and compete head-to-head with non-concentrating PV.
Date: Tuesday, September 27, 2011
Time: 2:00 p.m. EST/11:00 a.m. PST
Speaker: Dr. Jan-Gustav Werthen, Senior Director of Photovoltaics, JDSU; Moderator: Brett Prior, Senior Analyst, GTM Research
Can’t make the live event? Register and the presenters will alert you when the on-demand version is available.
Register to the webinar to hear about the technologies and new breakthroughs that promise continued improvement, including multijunction cell design and high-volume manufacturing techniques. At the end of the event, audience members will be able to ask questions of the panelists and moderator live!
On another note – here are a few helpful links for those interested in solar:
State and Federal Rebates and Incentives: www.dsireusa.org
Improving your building’s energy efficiency:
Join thousands of fellow supporters in a historic call for clean energy: www.repoweramerica.org/wall/#
For those interested in PV systems, GTM Research and Dupont are presenting a webinar. It is for system developers, system designers, EPCs, installers, financiers, engineering firms, and others who specify, recommend, or influence the selection of PV equipment and components (cells, modules, etc.) for PV installations. The event is sponsored by DuPont.
Over the next five years, photovoltaic (PV) systems will achieve grid parity in many major global markets with low-cost, high-efficiency systems that have 25 or more years of system life. A driving factor in achieving grid parity is the quality and durability of materials in PV cells, modules and other system components. This seminar will explore the crucial role of materials in determining the efficiency, reliability and cost of PV systems. Discussion will focus on key considerations, and provide guideposts for those who specify or influence the selection of PV components.
Date and Time: Thursday, July 28, 2011 at 2PM (ET). For additional info and to register for the PV Systems webinar visit Greentech Media here.
Overall, 2010 was a good year for the PV industry. But, the global PV industry is getting complex as it becomes more and more competitive. What’s the outlook PV technology, production and cost for the next five years?
You can find out what Greentech Media’s Senior Analyst Syyam Mehta thinks during an upcoming webinar. Mehta will discuss findings from the third edition of GTM Research’s PV supply chain report, PV Technology, Production, and Cost Outlook: 2010-2015. The webinar will cover topics such as: Read more
Organized by Greentech Media, the upcoming Networked Solar Conference will highlight the convergence of renewable energy and the smart grid. Industry experts from both fields will be on hand to answer questions such as:
- How is the Smart Grid evolving, and what values will it bring to utilities and consumers?
- How are innovations in solar tech and systems enabling the convergence of solar and smart grid?
- What impact does renewable energy have on the utility grid today, and tomorrow?
- How is solar a critical part of utility renewables portfolio?
- How will this convergence of solar and smart grid enable jobs growth?
The conference will be held on January 25-26, 2011, in Jersey City, NJ. What can you expect? Insights from Wall Street financial experts, policy makers of New Jersey, and leading industry research analysis of GTM Research.
What is the future of the convergence of renewable energy and the smart grid?
Will Federal incentive programs help change the agriculture industry by encouraging more farms to install solar energy systems? Reports suggest they will for some firms in Virginia.
A federal incentive program could forever change the face of Virginia’s agriculture industry by encouraging more farms to install solar energy systems.
That’s the hope of Blue Crump, owner of Fan-based Cityspace Construction and Cityspace Solar. Crump recently started pitching solar installations to local farms using government grants and credits as a tasty carrot.
Cityspace’s first agricultural project is the new wine-tasting room at Cooper Vineyards in Louisa County. Fifty-five percent of the cost for the facility’s 5.8 kilowatt solar array will be covered by federal incentives.
That’s because the federal stimulus bill extended a renewable energy incentive program to businesses and provides a 30 percent grant or tax credit toward the cost of wind, solar or other systems. In addition, a grant offered by the USDA through the Rural Energy for America Program offers agriculture-based business a 25 percent credit.
“The idea of renewable energy and sustainable agriculture just go hand in hand,” Crump said, adding that the investment pays off in seven to 10 years. (Read Al Harris’ full article at Richmond Biz Sense here)
The U.S. Dept. of Energy is another resource for funds and the Virginia Department of Mines Minerals and Energy is seeking $15 million plus in stimulus funds for renewable energy grants and rebates for both households and businesses.
Reuters is reporting that the world’s largest solar power station will be located in Australia. Here’s an excerpt and link to the full story:
SYDNEY (Reuters) – Australia plans to build the world’s largest solar power station with an output of 1000 megawatts in a A$1.4 billion (US$1.05 billion) investment, Prime Minister Kevin Rudd said on Sunday [May 17, 2009].
The plant would have three times the generating capacity of the current biggest solar-powered electricity plant, which is in California, Rudd said during a tour of a power station.
Tender details will be announced later in the year, and successful bidders will be named in the first half of 2010. Rudd said the project was aimed at exploiting the country’s ample sunshine, which he called “Australia’s biggest natural resource.” [FULL STORY HERE]
Task Force Focuses on Green Jobs as a Pathway to a Strong Middle Class
The White House Task Force on Middle Class Families, led by Vice President Joe Biden, held its inaugural meeting on February 27 in Philadelphia at the University of Pennsylvania. The Task Force has a simple mandate: to find, highlight and implement solutions to the economic challenges facing the American middle class. With President Obama announcing last week more than $20 billion for investment in a cleaner, greener economy – including $500 million for green job training – the Task Force’s first order of business is to evaluate what investing in green jobs will mean for middle class families.
After VP Joe Biden presented at the Middle Class Task Force Meeting and discussed the $19 billion of the American Recovery and Reinvestment act that is dedicated to renewable energy. Solpower Jobs, a green web recruiter, believes Biden’s plan lacks foresight (Source: PRWEB and Solpower jobs).
Vice President Biden said,
“We all know that the existing electrical grid today is inadequate, insufficient and outdated. For example, of all the wind power that we’re talking about being able to create in the Midwest and North Dakota, South Dakota, Iowa and other plain states, (has) significant potential. But it cannot carry that energy right now to population centers that need the electricity most without a new transmission superhighway.”
Solpower jobs remarked on Biden’s meeting the next day saying,
“there is no doubt that smart grid technology is an improvement over the current electrical grid but… The current administration has not recognized the self sufficient decentralized energy sector.” Solpower jobs continued to bash the plan and proposed that building self powered homes was a better use of the budgeted funds.
Vice President Biden’s proposal would spend $11 billion of the $19 billion to build “The Transmission Superhighway” which the US Energy Department believes could provide the US with 20% wind energy. Additional information is available at the U.S. Department of energy website.
Additional Background on the Task Force
The Middle Class Task Force, chaired by Vice President Biden, is working with a wide array of federal agencies that have responsibility for key issues facing the middle class to expedite administrative reforms, propose Executive orders, and develop legislative and policy proposals that can be of special importance to working families. One of the things that makes this task force distinctive is it brings together – in one place – those agencies that have the most impact on the well-being of the middle class in our country. For more information, visit www.AStrongMiddleClass.gov.
Is VP Biden’s focus on the transmission superhighway a wise use of the money? Or, is more critical thinking and brain power needed to address our nation’s power dilemma?