Letters: May/June 2009
Shower Faucets Frustration
I am in the energy contracting and consulting business and just built my own home. Needless to say, it is very efficient and very green, including solar hot water. I learned a lesson I would like to share.
We were sent to a large national plumbing warehouse—Fergusen—to pick out plumbing hardware and chose different manufacturers’ equipment for each of our three showers—a Moen, a Kohler, and a Hans Groehe. We moved in last August, when the solar water heater was putting out its maximum for the year.
We immediately noted that none of the three shower faucets had a volume control—they are on full blast at all times and all you can do is adjust the temperature. This uses more water than necessary—some of it hot water. The fact that this problem occurred across separate brands leads me to believe that it is a significant problem.
I spoke with each of the three manufacturers and they all suggested changing the valve inside the wall—to the tune of hundreds of dollars each and drywall repairs. Only Moen had an alternative solution—install a small quarter-turn shutoff valve just behind the showerhead so that you can reach up and partially turn off the water when needed. This is not a viable solution for children or short people.
None of the manufacturers were interested in marketing an old-fashioned volume-controllable shower valve as being “water friendly” or “appropriate for solar water heating systems,” and none of the three would offer me a discount on a replacement valve.
Maybe I am not paying attention here, but I have not seen this problem addressed in the efficiency world.
Energy Services Group
Author and Lawrence Berkeley National Laboratory researcher Peter Biermayer replies:
Typically manufacturers make two kinds of shower mixing valves (not part of the showerhead); valves that control the flow and temperature separately and valves that only control the temperature. The type that only allows for temperature control are often used by hotels and apartment buildings. To avoid thermal shock (a sudden change in temperature) and scalding, codes require shower-mixing valves to limit the change in temperature caused due to pressure changes in the cold or hot water line. Some of these mixing valves are pressure compensating and some (thermostatic type) regulate the flow based temperature changes in the water lines. These valves are tested for compliance at a flow rate of 2.5 gpm.
In your situation, you might consider a lower flow showerhead or installing a pressure-reducing valve upstream of the shower. Some shower mixing valves are designed such that you can install a different type of cartridge without having to remove the entire valve.
Which Whole-House Fan Is Best?
With summer right around the corner, I’m interested in having a whole-house fan installed to keep us cooler. There are a number of manufacturers, and Pacific Gas & Electric (PG&E) is offering a small rebate, but I’d like to find the best one to install. Any suggestions you can offer are welcome.
David Springer, author and president of the Davis Energy Group, replies:
In the mid-80s, we did a comparative test of whole-house fans for the Sacramento Municipal Utility District (SMUD), using my house as the test site. We purchased, I think, six of the most-popular brands at the time and tested them for air flow, noise, and power consumption (watts/CFM). Unfortunately, I believe that all the fans tested are no longer made. However, the preferred characteristics were large blade surface area and low rotations per minute (rpm). Lower rpm and less noise was provided by belt drive models.
Since the study for SMUD, a different configuration of fan has been developed by Tamarack, and others sell a similar design. They use two small- diameter fans with a motorized insulated shutter. The shutter is a definite plus. They don’t move as much air, but we have found from our studies of night ventilation cooling that moving about 0.6 CFM per square foot over the entire night provides more-efficient cooling than moving a large volume of air for short durations during evening and morning hours. They are also probably much quieter than the 24-inch or 36-inch fans commonly available. I definitely recommend a speed control, and a timer is also useful.
Seeking Info on Aeroseal
I would like to find out from you your opinion about the duct sealant product Aeroseal.
This is a quote from your Web site (www.homeenergy.org/archive/hem.dis.anl.gov/eehem/98/980113.html):
“The cost of sealing an existing duct system with Aeroseal is between $450 and $600, depending on what needs to be done, roughly the same as the cost of hand-sealing though less labor intensive. When sealing new homes, this product can be rolled into a total package of improvements provided to the builder, perhaps to qualify for the Environmental Protection Agency Energy Star Home Program.”
Since this information is old, I needed the latest update on this product. I especially want to know if there is any health hazard associated with this product.
Mark Modera, author and director of the Western Cooling Efficiency Center, replies:
I am the inventor of the process (the product already existed), and therefore I am not sure that I can give an unbiased opinion. That said, I still believe in the process.
The prices you found on the Home Energy Web site are lower than what current dealers are charging, at least in existing homes. I believe that most current residential dealers charge $1,000–$2,000 for an existing home. For new construction I have seen prices as low as $400–$500. There is a chance that the residential prices could drop based upon changes in how it goes to market.
We have never found a health hazard with the sealant over the 15 years that it has been in use. With more than 30,000 homes having been sealed over that time period, I fielded one complaint from a lady who said she smelled sealant continually after the job was done (as it turned out, she was running two ozone generators). I also had one contractor tell me that he found mold growing on the sealant; however, my take-away was that that must have been an existing problem and unique to that house, as we never heard of such a problem from anywhere else, and it was inconsistent with the UL testing that we had had performed.
I installed my present water heater in 2003. The copper pipes are connected directly to the water heater. One person said I need to use the special fittings to connect the copper pipes to the water heater or corrosion will occur. Another person said I could just run a wire from the input pipe to the output pipe, and that would short-circuit the electric charge that causes the corrosion. Is this correct?
Does it matter how close the wire is to the water heater? If so, how close does it need to be? Does the gauge of the wire matter? Does it matter if it is copper or aluminum wire (I have some aluminum wire I bought to ground my roof TV antenna)?
Thank you for your advice.
Technical Editor Steve Greenberg replies:
There should be some sort of insulating fitting (either a dielectric union or flexible connectors with integral insulators) between the copper fittings and the steel tank. Otherwise you’ll get corrosion. The jumper wire often seen at water heaters is to ensure that both the hot and cold water pipes are electrically grounded (this is an electrical safety issue). Installing a jumper between the pipes won’t stop the galvanic corrosion caused by dissimilar metals in solution (water) and in contact with each other.
Hope this helps!
Energy Use, Exposed
I liked your editorial “How Private Should Utility Bills Be?” (March/April ’09, p. 2). A few months ago I suggested to the Obama transition team at www.change.gov that the White House post its monthly energy consumption. Clinton, Bush, and Obama all publicized their intent to green the White House, but as W. Edwards Deming said, “In God we trust, all others bring data.” If the idea catches on it might be fun to see the household consumption for cabinet members, heads of various federal agencies, and so on.
On a related topic, are you aware that Madison Gas & Electric (MGE) offers average energy use and cost for any residential address via the Web? Here’s the URL, and if you want to look up my house, the address is 121 Leon St:
Customers can remove their consumption from the Web by opting out. However, the Public Service Commission of Wisconsin requires making high/low or average consumption available to the public, so this info would still be available by phone. Making consumption info Web-based saves our call center a lot of time. Madison is a university town with lots of renters who move frequently. MGE encourages renters to find out consumption history before signing a lease, so they’re not unpleasantly surprised.
An article in the Madison alternative weekly Isthmus used this Web page to publish the consumption of several local politicians and celebrities, but this didn’t ruffle any feathers as far as I know.
Another tool on mge.com calculates a home heating rating (if the customer has 12 months worth of gas consumption), but it’s password-protected: www.mge.com/myaccount/viewenergy.htm.
This tool allows customers to compare their homes to others of the same size, built in the same decade. We constructed the tool by merging data from the City Assessor (square footage and date built) with gas consumption.
We’re in the process of developing a similar comparison tool for electric consumption.
Here’s a screen shot of the rating for my house:
Another new site attempts to harness the power of social networking to reduce carbon dioxide emissions:
MGE created this site in cooperation with the University of Wisconsin’s Center for Sustainability and the Global Environment (SAGE) and 1000 Friends of Wisconsin. Unlike other carbon footprint calculators, gas and electric consumption is automatically pulled in for MGE customers. Users must enter the transportation consumption, however. Also, the electric emissions factors are specific to Wisconsin. For a story about co2gether.org, see: www.madison.com/tct/mad/topstories/315294.
Residential Services Manager
Madison Gas and Electric Company
In Steve Mann’s column, “Energy Efficient Mortgages” (March/April ’09, p. 10), the Figure 1 flowchart (p. 10), outlining a typical EEM workflow, was provided courtesy of Chris Cone, Chris Cone Consulting, and Jana Maddux, CHEERS.
In the article “Confessions of a Sinner,” (March/April ‘09, p. 18) the conversion of euros to dollars is wrong. At the time the article was written, the euro was worth approximately 1.38 U.S. dollars. In the article, for example, 800 euros was converted to 580 dollars, when it should have been converted to approximately 1,100 dollars. The editors regret the error.
I’m only now reading the Nov/Dec issue, and the thermostat story by Marianne Armstrong (“Thermostat Setbacks—Do They Really Work?” p. 38). On page 39 the author explains how the “sunny” and “cloudy” description refers to (1) a difference (inside/out) of 68°F and (2) a difference of 41°F. In both cases the article includes the centigrade equivalent: 68°F = 20°C, and 41°F = 5°C.
I agree that the degree conversions are correct, but the calculation is incorrect. The author’s point is to describe the magnitude (delta T) of the difference (in/out).
The equivalent to a 68°F difference between in/out is not 20°C. Rather, it’s the absolute value of what 68°F is, converted to °C. In the case of 68°F, it’s the absolute value of (20°C) plus (18°C) or a total of 38°C. In the case of 41°F, it’s the absolute value of (5°C) plus (18 °C) or a total of 23°C. Why the parentheses enclosing temperatures in the last two sentences?
Thanks. Keep up the good work.
Washington Electric Co-op, Incorporated
East Montpelier, Vermont
The editors reply:
Thanks for noticing this error, Bill, and sorry for the confusion it must have caused other readers. In fact, the author originally gave the information in degrees Celsius. We have a practice of converting into degrees Fahrenheit and then giving the Celsius temp in parentheses. So she meant a difference of 20 degrees Celsius and a difference of 5 degrees Celsius. We screwed it up by making a conversion that didn’t make sense. Some quick calculations show that a difference of 20 degrees Celsius is equivalent to a difference of 36 degrees Fahrenheit, and a difference of 5 degrees Celsius is equivalent to a difference of 9 degrees Fahrenheit.
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