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Balance Energy Expenditures for Maximum Return on Investment InspectAPedia®  -     How low should the BTU/hour loss be on an old, leaky wood frame house before adding solarizing with solar heat? How should the basement be insulated - around the perimeter or under the first floor? Questions & answers about how to prioritize spending on saving energy in buildings: priorities in reducing electricity bills, heating bills, cooling bills Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices

This article explains the basic priorities of steps to take in reducing building heating or cooling costs to obtain the maximum economic return when installing solar heating systems.

Readers should also see ENERGY SAVINGS PRIORITIES and see the collection of energy saving articles at ENERGY SAVINGS in buildings. Our page top photograph shows solar panels, both photovoltaic and domestic hot water heating systems, on a rooftop in Surprise, Arizona. The accompanying text is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

© Copyright 2012 InspectAPedia.com, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use page top links to major topics or use links at the left of each page to navigate within topics and documents at this website. Green links show where you are in a document series or at this website.

How to Maximize the Return on Energy Savings Retrofits & Solar Energy Systems

The link to the original Q&A article in PDF form immediately below is followed by an expanded/updated online version of this article.

• Q&A on Balancing Act - how to get the largest return on investment in energy efficiency - PDF version, Use your browser's back button to return to this page

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

Balancing Act - how to get the most return on energy efficiency investments

Question:

I understand the importance of insulating a house before installing any solar space heating system. (See INSULATION LOCATION - WHERE TO PUT IT).

How low a Btu/hour value should I attain in a 60-year old, leaky, wood frame house before solarizing? The house is 1900 square feet, has oil / hot water heat, and is located in Maryland (4000 heating degree days).

Also, how should the basement be insulated - around its perimeter or under the first floor?

Our photo (above left) shows a building insulation retrofit project in process where the owner was removing the original brick wall lining to install building insulation. Details of that project are at BRICK LINED WALLS.

Answer:

If you want to get the largest return on your investment in building energy efficiency, you should balance your expenditures on

• energy conservation
• solar energy
• auxiliary equipment

so that your economic return is equal for each.

Whatever analysis you use to make economic decisions

• Simple payback calculation on energy savings projects - how many years until the energy savings pays back the cost of the energy improvement
• Life-cycle costing calculation on energy savings projects - adds consideration of the costs of maintenance, repair, replacement of the energy improvement
• Return on investment calculation on energy savings projects - adds consideration of the alternative rate of return if the money spent on energy improvement were invested elsewhere

you should apply the method fairly to each part of the house. How much you want to spend in total will depend on what return on your money you find acceptable.

Law of Diminishing Returns on Energy Savings Investments

In general, the first dollars invested in energy savings will bring larger returns than later dollars due to the law of diminishing returns.See ENERGY SAVINGS PRIORITIES for details.

To be fair, you should apply your cost accounting only to the energy cost of a building part, if it serves another function (for example a window decoration, structure, or added living space).

In the case of an upgraded heating system, you should consider the added cost over the conventional equipment that you would otherwise install. There is a good deal of fudging and judgment in all this and plenty of room for common sense.

Placement of Basement Insulation

As for basement insulation, either approach will work. Of course, if you want a heated basement you should insulate the perimeter. Also, if you insulate the floor above the basement, you increase the risk of freezing pipes in the basement.

If the basement is mostly below grade and has no leaky doors and windows, this shouldn't be a problem in your climate.

See INSULATION LOCATION for BASEMENT for detailed suggestions about basement insulation. Also see INSULATION LOCATION - WHERE TO PUT IT.

The question-and-answer article about energy savings investment strategy when adding solar heat, quotes-from, updates, and comments an original article, (see links just above) from Solar Age Magazine and written by Steven Bliss.

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  ENERGY SAVINGS MAXIMIZE RETURNS ON

• Solar Age Magazine was the official publication of the American Solar Energy Society. The contemporary solar energy magazine associated with the Society is Solar Today. "Established in 1954, the nonprofit American Solar Energy Society (ASES) is the nation's leading association of solar professionals & advocates. Our mission is to inspire an era of energy innovation and speed the transition to a sustainable energy economy. We advance education, research and policy. Leading for more than 50 years. ASES leads national efforts to increase the use of solar energy, energy efficiency and other sustainable technologies in the U.S. We publish the award-winning SOLAR TODAY magazine, organize and present the ASES National Solar Conference and lead the ASES National Solar Tour – the largest grassroots solar event in the world."
  
• Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
  Excerpts with updates and annotations expanding the original Best Practices Guide text can be found in the online review and book summary at BEST CONSTRUCTION PRACTICES GUIDE and also at DECK & PORCH CONSTRUCTION, at INDOOR AIR QUALITY IMPROVEMENT GUIDE, and in other articles found at InspectAPedia.com such as HOUSEWRAP AIR & VAPOR BARRIERS, SOUND CONTROL in buildings, and other topics.
• Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. Thanks to Alan Carson and Bob Dunlop, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education including the ASHI-adopted Home Inspection Training Program (home study course), publications such as the Home Reference Book, report writing materials including the Horizon report writer, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
• Passive Solar Design Handbook Volume I, the Passive Solar Handbook Introduction to Passive Solar Concepts, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v1.pdf
• Passive Solar Design Handbook Volume II, the Passive Solar Handbook Comprehensive Planning Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v2.pdf [This is a large PDF file that can take a while to load]
• Passive Solar Handbook Volume III, the Passive Solar Handbook Programming Guide, in a version used by the U.S. Air Force - online version available at this link and from the USAF also at wbdg.org/ccb/AF/AFH/pshbk_v3.pdf
• The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the The Passive Solar Design and Construction Handbook, Steven Winter Associates (Author), Michael J. Crosbie (Editor), Wiley & Sons, ISBN 978-047118382 or 0471183083 is available at Amazon.com and via the InspectAPedia Bookstore
• "Passive Solar Home Design", U.S. Department of Energy, describes using a home's windows, walls, and floors to collect and store solar energy for winter heating and also rejecting solar heat in warm weather.
• "Solar Water Heaters", U.S. Department of Energy article on solar domestic water heaters to generate domestic hot water in buildings, explains how solar water heaters work. Solar heat for swimming pools is also discussed.
• "Heat Exchangers for Solar Water Heating Systems", U.S. DOE describes the types of solar water heater heat exchange methods between the sun and the building's hot water supply
• "Heat-Transfer Fluids for Solar Water Heating Systems", U.S. DOE, describes the types of fluids selected to transfer heat between the solar collector and the hot water in storage tanks in a building. These include air, water, water with glycol antifreeze mixtures (needed when using solar hot water systems in freezing climates), hydrocarbon oils, and refrigerants or silicones for heat transfer.
• "Solar Water Heating System Maintenance and Repair", U.S. DOE
• "Solar Water Heating System Freeze Protection", U.S. DOE,using antifreeze mixture in solar water heaters (or other freeze-resistant heat transfer fluids), as well as piping to permit draining the solar collector and piping system.
• "Scaling and Corrosion in Solar Water Heating Systems", U.S. DOE
• www.energysavers.gov/your_home/water_heating/index.cfm/mytopic=12850 is the base U.S. DOE website for these articles
• "Active Solar Heating Systems", U.S. Department of Energy, including
• "Radiant Heating Systems" U.S. DOE
• "Absorption Heat Pumps & Coolers", U.S. DOE
• "Solar Air Heating" U.S. DOE also referred to as "Ventilation Preheating" in which solar systems use air for absorbing and transferring solar energy or heat to a building
• "Solar Liquid Heating" U.S. DOE, systems using liquid (typically water) in flat plate solar collectors to collect solar energy in the form of heat for transfer into a building for space heating or hot water heating. The term "solar liquid" is used for accuracy, rather than "solar water" because the water may contain an antifreeze or other chemicals.

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

• Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
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