I have to get a water heater for the shop bathroom shortly. Expected use is infrequent, but there is a shower. There’s a vanity and a toilet, and no other fixtures. The subpanel is 100A and it’s already in. We have a propane tankless for the house but I have no plans to run gas to the shop, and no interest in expanding our use of gas. My question is, does anyone have experience with an electric tankless that would be adequate for this application without dimming the lights and causing the tablesaw to stall? The only one I’ve seen was installed for a whole house and had (I think) three 60A breakers.
Backup plan is a small electric tank.
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I think it's gonna be tough to power a tankless that can handle a shower with your 100A panel.
Perhaps a tiny elec. tankless for the sink and a standard electric (40 gal or smaller?) for the shower. That way, you can turn off the 40 gal when not needed. Of course, you need to know ahead of time that you'll need a shower. . .
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Maybe a 30 gallon tank on a switch or a timer? All the electric tankless models I've heard of use a lot of power, and I don't think you'll get around that if you need the throughput to heat water for a shower and a tap at the same time. Or even just the shower, really.
zak
"so it goes"
I did a little reading and it seems you guys are right. The smaller units seem to use 2 x 40A breakers, which is most of the subpanel capacity. Maybe I'm going to have to rethink the gas and get another Takagi.
I don't know how legal they are here.... but a guy on ebay sells an electric instant hotwater heater that fits directly to your shower head.. ad claims they are used all over europe and down under... i think it was 120v 30amp sealed unit... that and a 4-6 gal undercounter unit would be cool...
p
>>>but a guy on ebay sells an electric instant hotwater heater that fits directly to your shower head.
Caveat Emptor.
I can't imagine a unit like that being either safe or effective. Besides, having that amount of electrical current sharing the shower with me gives me serious 'shrinkage'.
Scott.
Always remember those first immortal words that Adam said to Eve, “You’d better stand back, I don’t know how big this thing’s going to get.”
Edited 8/15/2006 1:47 am by Scott
having that amount of electrical current sharing the shower with me gives me serious 'shrinkage'.
LOL I thought about that but is it really any different than an electric water heater and it all plumbed in copper? your link seems the same...
p
I know the thing you are speaking of. Have you considered just how you'll plug it in? European? Sure... you want 220 volts hanging from your shower head? UL Listed for safety? Don't bet on it.
They have millions of them in the UK. When I was there some were rated at 8kw. This was just enough for heating cold water in the winter. They run on 240v and work like a small tanked electric heater.
It would take so much power to heat the water, the local power plant would shift into second gears and brown outs across the county.
thats why you have to take turns!!
Well, if the Brits do it, it must be OK. Of course, their entire electrical system is different, with entirely different wiring practices and materials. I cannot advise buying this thing and trying to make it work here. I'd rather try driving on the other side of the road, than have one of these in my shower.
There are a few things the US should adopt from the UK. I miss having a fuse on every thing you plug in. (fitted in the plug) sockets are wired on a ring method. Lights and sockets do not share circuits. But everything is 240volt, so less effect from volt drop.
Maybe it's time to upgrade the shop to 220v. Gives your tablesaw an extra "kick" too :)
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Nothing stopping me from using 220/240 breakers, it's just that the load of an electric tankless unit seems quite close to the capacity of the feeder wire. I think we're going to have to go with a tank.
A tankless system should be plenty to wash your hands with occasionally.
Why do you need hot water in the shower?
Not to hijack the thread, but I was told at a home show to steer clear of tankless water heaters (by a tankless water heater dealer) because I had a slighty high mineral content in my water supply...there's a valve that is apparently very expensive and/or difficult to change out that would need replacing fairly often if exposed to my type of water. FWIW
Thats why You install a water filter to remove the "junk" from the water. I have the bosch aquastar (five years now) very happy with it.