Runs with Bison
Member
Yeah, I've had "issues" with the president of EcoInnovation's sometimes overzealous marketing (and his screaming about his competitors), which is why I'm awaiting 3rd party test results to show up on the NRCan list.
This seems to be pretty common with small vendors. I'm of the opinion that it is best not to oversell something. It is better to over deliver than under deliver. It doesn't do anyone any good to sell somebody something that doesn't fit their application. My personal numbers might come out wrong at times because I missed something, but it isn't intentional or an attempt to misrepresent.
Full disclosure: I went with a 4" x 4' PowerPipe in my system. I haven't instrumented it to verify effieciency, but it presents far less head to the DHW flow than a tankless HW heater(!). I'd have gone with a taller one if I had the space.
I used the GFX data to work up heat transfer coefficients and create estimates of the maximum I might expect to recover from the two showers it could be connected to. With my low flows and short showers it works out to only about 30 ccf/year with a 60" G3 GFX in the 3" drain size. It wouldn't surprise me if it was 5 ccf/year less due to dead volume/lag effects--this is a large relative effect for our short duration shower habits. The 60" S3 would yield about 28 ccf/year but would allow for three simultaneous shower operation.
The 60" would be a bit tight, but should fit my application. Failing that I would drop down to 40".
That's a good point about taking less pressure drop than a tankless.
The typical target market for these is pairing with electric water heaters since the energy cost for heating water that way is about twice as great. I can't support much capital at $25-30 year savings...but at $50-60/year I could make a case for it. If we took 10-15 minute showers and/or 2.5 gpm showers then it would also greatly improve the economics. DWHR makes a fair bit of sense for the colder climates with several months more per year of very cold supply water.