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RE: Tankless whole-house water heater

To: "shop-talk" <shop-talk@autox.team.net>
Subject: RE: Tankless whole-house water heater
From: "Randall" <tr3driver@comcast.net>
Date: Wed, 1 Mar 2006 11:45:06 -0800
> FWIW, I belong to Gold's Gym.  They moved to a new location a few
> years ago
> and remodeled the building to suit their needs.  They installed three big
> tankless units on an outside wall opposite the two locker rooms.  So far
> they seem to work fine, plenty of hot water.

Whatever flow rate & rise they will supply, they will supply indefinitely.
So you never "run out" of hot water like with a tank.

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 !

Ok, so do it with natural gas (which is far cheaper for me anyway) ... the
biggest unit I found just now is priced at $2200 + professional
installation, and will handle less than half my estimated requirements.

Granted my requirements are on the high side, but I really hate having my
shower suddenly turn cold when someone turns on a faucet.   My current 50
gal hot water tank won't support all that for long either, but at least it
degrades gradually.

And all this to save perhaps 10-20% of my natural gas bill.  I pay roughly
$100/mo for nat gas, so the projected savings is $20/month.  $2200/20 = 9
years just to break even, ignoring interest I would have earned if I'd kept
the money in the bank.

Randall




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