Introduction
There are so many reasons to reduce your energy consumption and then meet that consumption with renewable energy. Since we purchased our home in 2007, we added insulation, replaced windows, sealed leaks and installed a solar water heating system. We took these steps to insulate ourselves from rising energy costs and because it made economic sense; the solar water heating system we installed will pay for itself within 11 years, based on the energy saved, and is expected to last 30 years. Whatever your reasons, the following suggestions for prioritizing will help you decide where to begin.
The first and best way to reduce the energy footprint of your home is to design it to work with the environment instead of against it. If your house already exists, energy conservation yields the largest reduction of energy in exchange for your time and money. The next biggest bang for your buck comes from directly heating water with the sun. Ironically, the most excitingly appealing improvement, a system that generates electricity from the wind or sun, is the last thing to consider, based on return on investment.
In Kittitas County, people have done all of these things and, for the most part, what they have done is working. They have built passive solar homes, they have built energy efficient homes, they have retrofitted homes to be more energy efficient, they have installed solar water heating systems and they have installed systems that produce electricity from the sun and wind. The purpose of this article is to share information and resources associated with these options based on what they have learned.
Passive Solar Design
Based on the national average, heating and cooling constitute 44% of home energy use. This amount can be reduced by half or more (even in cold climates), with little or no increase in construction costs by building a well insulated, well designed passive solar home. The goal of passive solar design is to manipulate components of the home to use the environment to heat and cool your home, without motors. The latitude of Ellensburg is 47 degrees N. At this latitude, the winter sun rises in the southeast, is low in the south sky at midday, and sets in the southwest. The summer sun rises in the northeast, is high in the south sky at midday, and sets in the northwest. This means the winter sun can be utilized and the summer sun excluded. The following are the practices that constitute passive solar design.
1. Orient the south face of the home to within 15 degrees of true south and choose a building site with no obstructions to the low angle of the winter sun.
2. Maximize exposure to the south by running the long, narrow axis of the house east west.
3. Install enough south facing glazing (e.g. windows and glass doors), but not too much, and balance it with thermal mass. The south glazing should constitute between 7% and 12% of the floor area (e.g. the square footage of south glazing should be between 70 sq. ft. and 120 sq. ft. for a floor area of 1,000 sq. ft.). Glazing in east and north facing walls should not exceed 4% and west facing glazing should not exceed 2% of the total square footage. Note: Windows with a low solar heat gain coefficient (SHGC) are readily available, but look for windows with a high SHGC (at least 0.52) for the south wall.
4.Install thermal mass, a 4 inch thick slab or 8 inch free standing wall, matte-textured and dark in color is ideal. A rule is to allow 6 sq. ft. of slab floor available to the sun for each square foot of south glazing beyond 7% (e.g. A 1,500 sq. ft. house with the maximum recommended 12% south facing glazing of 180 sq. ft. would require 450 sq. ft. of slab floor available to the sun).
5. Properly size overhangs (e.g. roof eves and awnings) to fully shade south facing windows in the summer and fully expose south facing windows in the winter. Sustainable by Design provides a Window Overhang Design tool at http://www.susdesign.com/tools.php making sizing overhangs easy.
6. Insulate beyond code requirements and eliminate air leakage.
7. Ventilate because a well insulated house in which air leakage has been eliminated, also minimizes air exchange between the inside and outside, which may result in poor indoor air quality. Conventional vapor barriers, venting and exhausting may not be enough. In the summer, in the evenings, ventilation can be achieved by opening windows to allow for cross ventilation, but when it is cold, this is a poor option because you lose precious heat. An energy recovery ventilator (ERV) or heat recovery ventilator (HRV) are options, they are devices that keep heat in the house while moving stale air out of the house.
Passive Solar Home, East of KittitasOne local couple that now lives in their recently completed well insulated, passive solar house, located east of Kittitas, is very satisfied with its performance. Last summer, they reported an interior temperature of 70 degrees F, when the exterior temperature was 95 degrees F. Tools they found useful were Google SketchUp that they used to create a 3D model of their home, which they added to Google Earth. Using these tools they were able to track the movement of the winter sun and the summer sun through the windows of their 3D model home.
For more information on passive solar design, fundamental resources include The Solar House: Passive Heating and Cooling by Dan Chiras and The Sun-Inspired House: House Designs Warmed and Brightened by the Sun by Debra Rucker Coleman.
Energy Conservation
If your house already exists, energy conservation is the first thing to consider. One element of energy conservation is energy efficiency improvements, including reducing air leakage, adding insulation, and upgrading windows. However, before beginning, hire a professional to conduct an energy audit or learn how to do it yourself. An energy audit will help you prioritize energy efficiency improvements. According to the advertising of one local energy auditor, the cost to audit most homes is $135.00 per thousand square feet. For low income households, free energy auditing services are available through the HopeSource weatherization program. We hired an energy auditor after buying our home when we began to receive $400 electricity bills as winter approached. He did a field visit and created a report for us, in which he recommended a number of energy saving actions including sealing the opening below the tub (which we didn’t even know existed), sealing around the pipes and wires, adding a vapor barrier and adding insulation. He addressed my concern regarding adequate ventilation, as air leakage is reduced, by stating, “we can reduce air leakage of many old houses by as much as ½ and still have good combustion safety and ventilation, but that we should continue to use good spot ventilation to clear our kitchen and shower steam and minimize indoor toxins.”
Once you know where to begin, the choices can seem overwhelming. The Efficient Windows Collaborative (http://www.efficientwindows.org/) offers a free window selection tool to compare the U-values, SHGC, and energy costs for windows from various manufacturers. There are two cities in Washington for which calculations have been made, I suggest choosing Spokane. Regarding insulation, the Oak Ridge National Laboratory offers a free Whole Wall R-value Calculator (http://www.ornl.gov/sci/roofs+walls/AWT/InteractiveCalculators/rvalueinfo.htm) for direct comparisons of different wall technologies.
Other energy saving actions, our energy auditor recommended, included replacing standard bulbs with compact fluorescent lamps (CFLs, he said, are number one in the effort to control global warming) and purchasing energy efficient appliances when they need to be replaced. Based on the national average, lighting, cooking, and other appliances (including the refrigerator) constitute 42% of home energy use. Energy Federation Incorporated (http://www.efi.org/) is one leading residential distributor of energy efficiency related products that provides information about these products and sells them through their on-line store. The ENERGY STAR program (http://www.energystar.gov/) identifies products that have earned the ENERGY STAR label by meeting energy efficiency requirements. And soon TopTen USA (http://www.toptenusa.org/default.htm) will help users find and purchase the most energy efficient products in the U.S. marketplace.
The other equally important element to conserve energy is to be thrifty, like clipping coupons where you save money with a little bit of effort, by doing things around the house a little bit differently, you save energy. Things you can do to save energy include using the clothesline instead of the dryer, taking short showers, turning the thermostat down, turning off lights not needed, eliminating phantom loads and closing and opening windows and covering them to employ the sun and wind for heating and cooling.
Solar Water Heating
After energy conservation the next lowest hanging fruit is installing a solar water heating system. Based on the national average, water heating constitutes 14% of home energy use. Installing a properly sized solar water heating system can save 60% to 90% of the energy used to heat hot water per year.
The best resource to learn about solar water heating, especially if you plan to install your own system, is the book entitled Solar Hot Water Systems Lessons Learned 1977 to Today by Tom Lane. According to him, “only two types of active systems can survive in climates that experience freezes every year …: closed-loop drainback systems and closed-loop anti-freeze systems with well thought out heat exchange… systems...” More specifically, his favorite system is a double-pumped drainback system with a heat exchanger in the drainback reservoir. Another resource, that is free, is the Department of Energy’s 2003 Consumer’s Guide entitled, “Heat Your Water with the Sun” (http://www.nrel.gov/docs/fy04osti/34279.pdf).
Systems that have been installed locally include a double-pumped drainback system coupled with flat plate collectors, pressurized glycol system coupled with flat plate collectors and pressurized glycol system coupled with evacuated tubes. Their owners are pleased with their performance, each of these systems are designed in such a way that they are not adversely affected by our cold winters.
A comparison of solar water heating systems is provided in Home Power’s 2008 Solar Water Heating Systems Buyer's Guide (http://homepower.com/view/?file=HP125_pg92_Marken). If you want to compare thermal collectors, the performance of different flat plate collectors and evacuated tubes is listed in Home Power’s 2008 Solar Thermal Collector Guide (http://homepower.com/view/?file=HP123_pg66_Marken).
Flat Plate Collectors; Part of a Double-Pumped Drainback Solar Water Heating SystemI discuss our 2008 investigation into solar water heating in detail in the 04-22-08 entry of this blog.
Generating Electricity from the Sun and Wind
Once you have shrunk the energy consumption of your home as much as possible, you can consider installing a system that generates electricity from the sun and/or wind.
Wind and Solar Combined to Produce ElectricityTopics including evaluating a site for solar PV potential, photovoltaic system types, system components, putting the system together, system design considerations and cost considerations are covered in the free Washington State University Extension Energy Program publication entitled “Solar Electric System Design, Operation and Installation An Overview for Builders in the U.S. Pacific Northwest” recently published in October 2009 (http://www.energy.wsu.edu/Documents/SolarPVforBuildersOct2009.pdf).
Topics including practicality of wind energy, wind turbine sizing, basic parts of a small wind electric system, cost of wind systems, installation and maintenance support, energy production of wind systems, evaluating a site for wind and connecting a wind system to the grid are covered in the free Department of Energy publication entitled “Shortcut to Small Wind Electric Systems-Washington Consumers Guide” published in August 2007 (http://www.nrel.gov/docs/fy07osti/41391.pdf).
Another valuable resource are Home Power magazines regularly published Buyer’s Guides on different components including the 2009 PV Module Buyer's Guide (http://homepower.com/view/?file=HP128_pg78_Sanchez), 2009 Grid-Tied Inverter Buyer’s Guide (http://homepower.com/article/?file=HP133_pg58_Mayfield) and 2007 Wind Turbine Buyer’s Guide (http://homepower.com/view/?file=HP119_pg34_Sagrillo).
Home systems that have been installed locally include independent and grid-tied photovoltaic and grid-tied wind. The types of wind turbines include the Skystream 3.7 on 33 ft. and 45 ft. monopoles, Bergey Excel-R (7.5 kW) and Bergey Excel-S, (10 kW) on a 100 ft. free standing tower.
Bergey Excel-S, (10 kW) on a 100 ft. Free Standing Tower Photo taken by Eric IrwinThe latter wind system is large enough that it produces the power required to run the home and more. The owners are compensated by the State of Washington for the excess electricity they produce at a rate of $0.12/kWhr up to $2,000/year.
One important thing to keep in mind with wind systems is investments in increased tower height can yield very high rates of return in power production. Ground drag is a significant adverse factor affecting production when located less than 66 feet from the ground.
Incentives
Incentive programs can substantially reduce installed costs. To view current state and federal incentives the Database of State Incentives for Renewables and Efficiency (http://www.dsireusa.org/) is the best resource. There are four types of incentives for residential renewable energy in Kittitas County.
1. Residential Renewable Energy federal personal tax credit for 30% of qualified expenditures for eligible technologies including solar water heat, photovoltaics and wind. It is set to expire on 12/31/2016.
2. 100% exemption from Washington State sales tax for eligible technologies including solar water heat, photovoltaics and wind. It is set to expire on 06/30/13, but may have already expired for solar hot water.
3. Production incentive between $0.12/kWh and $1.08/kWh (depending on project type, technology type and where equipment was manufactured) up to $5,000/year for eligible technologies including photovoltaics and wind. It is set to expire on 6/30/2020. Northwest Solar Center (http://www.northwestsolarcenter.org) lists eligible technologies manufactured in Washington.
4. Net metering; utilities are required to allow homeowners to hook eligible technologies including solar and wind to the grid. If you have questions about Washington State's Net Metering Law, the Washington State University Extension Energy Program created a Q & A sheet about it (http://www.energy.wsu.edu/documents/renewables/netmeteringlaw.pdf).
Permits
Contact the appropriate permitting entity to determine if a permit is required for you project.
Resources
For more information on passive solar design, fundamental resources include The Solar House: Passive Heating and Cooling by Dan Chiras and The Sun-Inspired House: House Designs Warmed and Brightened by the Sun by Debra Rucker Coleman.
Sustainable by Design provides a free Window Overhang Design tool at http://www.susdesign.com/tools.php
Google SketchUp is available to download for free at http://sketchup.google.com/download/index2.html
Energy-10 computer software is geared toward the professional. It can identify the best combination of energy-efficient strategies, including daylighting, passive solar heating, and high-efficiency mechanical systems. It can be purchased form the Sustainable Buildings Industry Council at http://www.sbicouncil.org/storeindex.cfm
Publications such as Home Power and Solar Today are excellent resources that cover all of the topics discussed in this article in greater detail. Attention to K-12 School Libraries, Redwood Alliance is offering free subscriptions to Home Power for K-12 school libraries. To complete the short online application go to http://redwoodalliance.org. To access the Home Power articles referenced in this article you must become a subscriber.
HopeSource Weatherization Service http://www.hopesource.us/html/weatherization.html
Efficient Windows Collaborative offers a free window selection tool to compare the U-values, SHGC, and energy costs for windows from various manufacturers http://www.efficientwindows.org/
Energy Federation Incorporated is a leading residential distributor of energy efficiency-related products that provides information about these products and sells them through their on-line store. http://www.efi.org/
The ENERGY STAR program identifies products, separated into categories, that have earned the ENERGY STAR label by meeting the energy efficiency requirements set forth in ENERGY STAR product specifications. http://www.energystar.gov/
TopTen USA will soon help users find and purchase the most energy efficient products in the U.S. marketplace. http://www.toptenusa.org/default.htm
The best resource to learn about solar water heating, especially if you plan to install your own system, is the book entitled Solar Hot Water Systems Lessons Learned 1977 to Today by Tom Lane.
Heat Your Water with the Sun, a free 2003 Department of Energy Consumer’s Guide http://www.nrel.gov/docs/fy04osti/34279.pdf
2008 Solar Water Heating Systems Buyer's Guide http://homepower.com/view/?file=HP125_pg92_Marken
2008 Solar Thermal Collector Buyer's Guide http://homepower.com/view/?file=HP123_pg66_Marken
I discuss our path to solar water heating in greater detail in the 04-22-08 entry on this blog.
Solar Electric System Design, Operation and Installation An Overview for Builders in the U.S. Pacific Northwest, a free Washington State University Extension Energy Program publication recently published in October 2009 http://www.energy.wsu.edu/documents/renewables/SolarPVforBuildersOct2009.pdf
Shortcut to Small Wind Electric Systems-Washington Consumers Guide, a free Department of Energy publication published in August 2007 http://www.nrel.gov/docs/fy07osti/41391.pdf
Home Power Magazine 2009 PV Module Buyer's Guide http://homepower.com/view/?file=HP128_pg78_Sanchez
Home Power Magazine 2009 Grid-Tied Inverter Buyer’s Guide http://homepower.com/article/?file=HP133_pg58_Mayfield
Home Power Magazine 2007 Wind Turbine Buyer’s Guide (http://homepower.com/view/?file=HP119_pg34_Sagrillo)
Database of State Incentives for Renewables and Efficiency http://www.dsireusa.org/
Q & A About Washington State's Net Metering Law produced by the Washington State University Extension Energy Program http://www.energy.wsu.edu/documents/renewables/netmeteringlaw.pdf
Northwest Solar Center
http://www.northwestsolarcenter.org
