> > But I just did a little calculation for my house. To support 140F water
> > (Yes, I like my hot water hot) and potential simultaneous use of 2
> > showers/tubs; a dishwasher; a clothes washer and a single
> faucet, I would
> > need somewhere around 130 kW ! At 240v, that's over 500 amps !
>
> That's a *huge* amount of simultaneous water usage.
True, but it accurately describes "worst case" in my own home. And it also
describes a situation that my current hot water system can handle reasonably
well, as long as the showers and faucet usage are short.
> We went tankless because I wanted the space where the water
> heater was. Tankless let us put the water heater in the attic, out of
> the way.
Very reasonable, but tanks can also be hidden away. Around here, they're
commonly placed outdoors, but attic installations are also possible. The
downside of an attic installation is what happens when (not if) it starts to
leak. A catch pan is mandatory of course, but I've seen leaks spray water
all sorts of places. Had one spray it straight up the flue, so the first
thing I noticed was hot water running off the roof !
> As for the professional installation, they're mostly not difficult for a
> DIY installer, I bolted ours up and it worked fine.
No argument, but the site I looked at said the warranty was void if not
professionally installed.
> In our case the biggest single 'Whoops!' comes if you've got two showers
> going and someone starts the clothes washer. The washer pretty much
> sucks all the hot water out of the house. Of course, since there's only
> two of us, that doesn't happen often...
As long as you know of the limitation, I guess it's OK. But when the wife
is cooking breakfast, it's entirely possible for her to decide it's time for
a load of dishes, while me & a kid (or guest) are each taking a shower. And
I have been known to decide I need a load of laundry done right now, before
taking a shower (which is why I went with a 50 gallon rather than 40).
> Problem is, once it's gone, it's gone, and you're waiting a good long
> time to get *any*.
Actually, the rise through my gas-fired tank heater is enough that I can
actually shower in it with only the shower running. Not 140F obviously, but
not ice cold either. The hot water never goes away entirely. In effect,
once the tank is cold, the heater functions as a 50k Btu tankless. I tested
this theory once, after learning the kid had turned the gas valve off the
day before & I had to shower for work.
Randall
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