Misleading domestic hot water recirculation numbers
The June 2017 PM article by Anthony Tosco, “Heat up your bottom line with DHW recirculation,” claims it saves an average of 12,000 gallons per year. Philadelphia reports average total water use per household is about 54,000 gallons per year, and that includes exterior use such as landscaping and car washing. Many other water suppliers report similar total consumption. Of course, only some fraction of that is hot water.
To claim that hot water recirculation can save 12,000 gallons per household per year seems much too high, especially without any measured or metered data. Maybe one-quarter to one-third of the total water use is hot water, so hot water may amount to 13,000 to 18,000 gallons per year.
One of my friends in Montgomery County meters his hot water at 15,000 gallons per year. To claim that recirculation “can save an average of 12,000 gallons of water each year” does not pass the red-face test, nor does it leave much hot water for bathing, washing, or cooking. Such claims should be fact checked and verified before publication.
Bala Cynwyd, Penn.
Thoughts on installing sump pumps
In regard to your excellent article, “Tips for Installing Sump Pumps,” in the October 2017 issue, I wanted to chime in with a couple of thoughts.
First, tough to tell from the picture on page 75, but it appears the discharge piping utilizes PVC DWV ¼ bends. DWV fittings meeting ASTM D2665 are rated at zero psi and should not be used in this application; rather, Schedule 40 pressure fittings meeting ASTM D2466 would be the appropriate choice.
I wanted to also mention that PVC “foam” or “cellular” core meeting ASTM F891 likewise is not designed for any pressure service, no matter how low the head and solid wall pipe should be utilized. I can’t tell you how many times over the years I’ve observed either the incorrect fittings, pipe, or both installed in this application.
I enjoy all of the BNP plumbing- and piping-related publications, as I like keeping current on products and issues.