Letters: September/October 2009
Dear Weatherization Family,
It is with profound sadness that I share the passing of our friend and colleague Alex Moore. On Sunday June 7, Tammy lost her husband, Madeline and Emma lost their father, and this network lost one of its truest champions, and without a doubt one of our greatest friends. I can’t begin to express how profoundly sad it is to have to share this information with you. The cause is still not yet confirmed, but is believed to have been a massive heart attack.
It is a rare day that you find an individual of Alex’s caliber. Since 1991, he poured himself into making Weatherization Work! He has been the senior advisor on all technical matters for the federal staff during his tenure as a contractor. It is hard to name anyone who has helped this network more with the incorporation of computerized energy audits, the development of core competencies, and the training and development of advanced technical skills in state and local staff. His technical proficiencies are unquestioned, but what was most remarkable about Alex was his ability to engage each and every person exactly where they are. He engaged us each in a way that made each of us better at our jobs, because he was so exceptionally good at his.
Today we grieve his passing. Today we know there will never be another with his unique abilities, his incomparable sense of humor, and his positive, can-do attitude. Today we mourn the loss of our friend. Tomorrow we will celebrate the pleasure we have had in knowing him. Tomorrow we will laugh as we remember the first time he showed us his “dance moves” or the way he put each of us at ease making jokes that only he could make. Tomorrow we will recognize that we will continue and be part of his legacy.
Jean M. Diggs
Energy Technology Programs Specialist
Office of Weatherization and
Weatherization Assistance Program,
Blocking Chimneys for Twenty-Four Years
Regarding the article on The Chimney Balloon (Mar/Apr ’09, p.14), I appreciate that there is a commercial product available for blocking old chimneys. The article states that a British engineer, David Woodman, developed the idea in 1989. A similar product was developed and tested in 1985 in Canada. Canada Mortgage and Housing Corporation (CMHC) published field test results on the product in 1988 under the title Davic Heat Barrier and found it quite successful at blocking old chimneys. The Davic product was sold for several years under different names.
Ottawa, Ontario, Canada
I have a small home in a ranch where there is no electricity and a generator proves to be quite expensive and noisy. I would like to know if there is someone out there who builds a rechargeable battery that I could use to provide energy to my vacation home. I need a battery that can store at least 2,000 kWh. Size is not a big issue as long as two people can carry it. If you know of a company that builds something like this, I would very much appreciate you pointing me in the right direction.
Technical Editor Steve Greenberg replies:
I think there's an order-of-magnitude error in the energy storage requirement you mention, as this is enough energy for 50 to 500 days in a residence, depending on a range of factors.
There are a variety of sources of batteries for such applications; for example (and this is not an endorsement), Real Goods. (See www.realgoods.com/product/id/1009479.do, a 370 AH (ampere-hour) battery that weighs 113 lb. This is a lead acid battery, which is the dominant technology for such storage, and lead is heavy.) Ignoring what voltage level, charging system, and so on would be used (and assuming they have zero losses, which isn't, of course, quite accurate), and assuming that for decent battery life only 50% of the nominal capacity is used in each discharge cycle, then (volts x ampere-hours = watt-hours) this battery will provide 6 x 370 x 0.5 = 1,100 Wh or 1.1 kWh. Call it 1 kWh for round numbers. For 2,000 kWh, you'd need about 2,000 of these, which would weigh over 220,000 lb or over 110 tons.
I suggest you find a local consultant for the design and installation of such systems. Remember that even more than in grid-connected homes, energy efficiency can be very cost-effective in off-grid homes, where wasted watts and watt-hours add up to big capital costs for the systems to serve them.
MPG for Homes
I just read your article “MPG for Homes” (May/June ’09, p. 28). I enjoyed it and agree that a standard assessment of MPG for homes would be great to see. My question is on the home heating index (HHI), and whether or not the heating system efficiency should be thrown in the mix. Tell me if I am right when I say that when you use the total number of gallons consumed of oil per year, you are looking at the efficiency of the building shell as well as the heating system efficiency, but if you multiply the number of gallons used times the heating system efficiency, you are looking at just the shell? Or is it ever done that way? I hope I am making sense. Thanks.
Author Allen Zimmerman replies:
I appreciate your kind words about the article. In response to your question regarding HHI calculations:
When the total seasonal energy (Btu) required for heating (obtained based on gallons of fuel oil consumed) is used in the calculation for HHI, the numerical result is the actual HHI of the home. This number accounts for both building envelope (shell) thermal performance and furnace system efficiency (combustion and distribution). If a value for the average overall furnace system efficiency is available, then this percentage can be used to calculate the gallons of fuel oil (and thus Btu) that are “lost” due to the inefficiency of the heating system. The remaining gallons of fuel oil (converted to Btu) can then be used to calculate the envelope (shell) HHI. As I note in the article, the envelope HHI can also be estimated via calculations based on design parameters such as R-values and air leakage rates.
Pure Energy Location Correction
We are a BPI Affiliate and employ certified Building Analysts and offer BPI-recognized training. The BPI ad in the July/August 2009 issue of Home Energy (pp 27–30) has the incorrect location of our company, Pure Energy. We are listed as number 62 in the list and on the map, but our actual location is in Eastern Pennsylvania, where you have Performance Systems Development located. It appears these two companies were reversed on the map.
A. Tamasin Sterner
Shower Faucets Frustration
I am writing in regard to Ed Minch's frustrating situation he has experienced with his new home solar system powered shower systems (“Shower Faucets Frustration” Letters, May/June ’09, p. 3).
I used to be in the decorative plumbing industry, and a manufacturer's representative for Hansgrohe. I suspect one of two things has happened here. Either Mr. Minch did not inform the salesperson of his solar powered shower systems or the salesperson was not properly trained. It is very rare for someone to have a solar powered water system for a complete house, so I am not pointing blame at the salesperson. In fact, in the 11 years I was in the industry, I never came across a whole-house solar powered water system, unfortunately.
All three of the manufacturers, Moen, Kohler, and Hansgrohe offer volume control valves. I always instructed all my customers (plumbing wholesalers) to include a volume control for all points of water exit on a shower system. There is the additional cost, but this is not the place to cut corners.
I would suggest the wholesaler, a plumber, a drywall repair contractor, and the customer sit down and work out a way to resolve this. For example, I would give the customer the valves and trim at our ultimate bottom line cost. This situation could probably be resolved if all parties agreed to give a little.
From Steam to Hot Water
I write in reference to Steve Greenberg’s article “Converting from Steam to Hot Water” (July/Aug '09, p. 6).
Mr. Greenberg’s treatment of the subject was incomplete. First, he left out two important points which argue against this type of conversion:
- There are many radiators out there that cannot be used with hot water at all. They were designed only for steam. If you try to run these on a hot water system, you'll get much less heat than you need, since the water cannot circulate through them properly. The job won’t work.
- Residential steam heating systems were designed to operate on a maximum pressure of 2 lb, and some of these were designed for maybe 8 oz—and this is on the coldest day of the year! Hot water runs at a minimum pressure of 12 lb in a two-story building, 18 lb or so in a three-story building, and if you get much higher than that, you can exceed the boiler's maximum working pressure.
This vastly higher pressure will do a great job of finding any weak spots in the piping and radiation. The resulting leaks will damage the building and possibly injure someone.
Mr. Greenberg also failed to mention two drawbacks of condensing hot water boilers:
- Some of these boilers have experienced total failure of their heat exchangers after only five years or so of operation. So the consumer pays much more for a unit that doesn’t last and leaves them without heat when they need it.
- Condensing boilers cannot be exhausted into a standard chimney, so typically they are exhausted out the sidewall of the building. This sidewall exhaust must maintain certain code-mandated clearances from windows or other penetrations, publicly accessible walkways (subject to local interpretation), snow line clearance, etc. In many cases, these clearances cannot be met without major alterations to the building.
All of these will put you on the wrong end of the customer’s lawyers, and are some of the reasons my company does not recommend or perform these conversions. Another reason is that we have a very good track record of fixing steam systems and cutting their fuel consumption.
Mr. Greenberg asserts that “hot water heating systems are more efficient than steam.” On what numbers does he base this statement?
Condensing boilers? Well, if you have to replace one of these after five years, you won’t save anything and will probably lose money. And maybe he doesn’t know that 90%+ efficiency is possible in a steam boiler. They don’t use condensing technology, of course. It’s been done elsewhere, but American boilermakers are dragging their feet in this.
Delta-T between the flame and the water? The higher delta-T in a steam boiler is made up by the higher delta-T at the radiators.
And don't forget, a gravity-return system does not need a pump. So a gravity-return steam system uses less electricity.
As far as I know, there has never been a scientific, apples-to-apples comparison of the relative efficiency of transferring BTU by steam as opposed to hot water. So any assertion that one is more efficient cannot be based on fact, but is instead based on that person's bias. Our readers deserve better.
Frank Wilsey, Vice President
All Steamed Up, Incorporated