Don't Forget Insulation
Thank you for publishing Leigh Marymor's article "Hot-Water Circulation" (12/10). It addresses a couple of my pet peeves: first, waiting for hot water to get to the tap; and second, the myth that a continuously circulating hot-water system saves energy. It seems that a circulating system can only save water, and - depending on the system - you will trade off energy use for time saved. With on-demand systems, you still have a slug of hot water left in the pipes after the tap is closed, just as you would in a noncirculating system. The energy it took to heat that water is wasted as it cools. In all cases, the shorter you make your hot water runs and the more you insulate them, the better.
I've insulated the water heater and all the accessible hot-water pipes in every house I've lived in. Insulating the pipes made a very noticeable difference; even 40 minutes after running hot water, if you used the tap again the water flowing from it was still warm - often warm enough that you didn't need to wait for "hot" water to arrive. I've also installed 3„8-inch-diameter tubing between the water heater and the kitchen sink. This cuts the wait time for hot water by about half. However, it also violates the plumbing code, last I checked. I don't suggest that readers should violate the code by running "undersized" pipes, but I certainly suggest changing the code: It's absurd to require pipe size adequate to deliver 5 gallons per minute while also requiring flow-restrictors on fixtures that limit output to 1.2 gallons per minute.
Thor Matteson, S.E.
Berkeley, Calif.
Thermal Solar Storage
Jon Vara's article regarding thermal storage tanks (Backfill, 12/10) overlooks another reason - besides storing summer heat for use during winter - for using thermal storage tanks. It's common to use solar collectors to capture daytime heat for use in radiant heating systems. The heat is gathered during daylight hours, though loads are highest overnight. Providing a storage tank allows one to install a larger collector system and store the excess heat energy for overnight use, radically reducing the need for backup fuel. Storage systems can provide sufficient capacity to carry heating loads for several days, even through a string of cloudy days.
Ed Van Petten
San Francisco
Time-Saving Sidewall Detail
On reading "EIFS Revisited" (12/10), I wanted to make a suggestion that may save some time and money down the road. When installing a wall cladding over an adjacent roof, wouldn't it make more sense to provide a removable, two-piece counterflashing that would allow for work to be done on the roof without disturbing the wall finish? Ideally, the termination for the EIFS could be high enough above the top of the step flashing's vertical leg to allow the flashings to be removed and reinstalled without removing any of the foam board.
The bottom of the termination - the "counterflashing receiver" in the sketch - should be a bit wider than the wall itself. Its hemmed lip would turn down just enough to facilitate the installation of a second vertical counterflashing, which would be inserted up behind the receiver's hem and pop-riveted. The hemmed drip at bottom should be kept clear of the finished roof surface by at least 1„4 inch to allow for water flow. Obviously, given the thickness of the wall shown on the detail, the step flashing on the roof might need to be installed over wood blocking, to bring it into the plane of the wall and make it accessible.
Harrison McCampbell, AIA
Nashville, Tenn.
