@Robert... That's cool. Like I said I don't know the math and I'm sure the tech has come a long way since I last looked into them. Still though if someone can afford a small PoU unit at the end of a long run obviously that solves the whole problem. Far more environment friendly too. I think the code problems back when I was thinking of buying one was the circuit stuff... at least for the big ones. They just had such a draw you had to install a special line and breaker for it all. Is that still the case or can they run on 220 lines?

Electric water (resitive element) heaters are effectively 100% efficient at transferring the heat to the water, so better insulation etc. is the only difference between them in that regard. The price is mainly due to the cost of materials and construction-a more expensive heater may last longer (or not).

Gas heaters can be designed so that less heat is lost up the flue, but the cost may not reflect that. 

An "instantaneous" heater (gas or electric) in which the cold water flows through heated coils does not lose heat when not in use and offers a significant energy saving in most cases. But it requires more power or combustion when active so the heating elements/exchanger are more expensive to make. 

If you live in a warm climate, a heat pump (reveres air conditioner) unit can save substantial energy, but the cost is much more than other water heaters, and there is probably going to be more maintenance (repair) cost over the life of the unit. If your water heater is sitting in a really cold place, then the efficiency drops to the point that many of these units are made with auxiliary electric heating coils that take over when the garage is too cold to provide the temperature difference the heat pump needs to function. The energy efficiency specifications of these units need to be interpreted carefully. A unit in a Florida shed will have quite different actual savings than one in an unheated Minnesota garage in winter. If you put one in a heated area, then you are actually paying for the heat that is transferred from the room to the water, so the real efficiency is much less.

dmbaer

RobertB

Even in an extremely large home, at worst, you will waste a quart of unheated water.

My home certainly isn't huge ... ~2000sq. ft.  The kitchen sink is at one end of the house and the water heater at the other.  I have to run close to 1.5 gallons of water before the water coming out the tap is actually hot.  But the worst part is that when done washing dishes, or whatever, I've heated close to 1.5 gallons of water that will just sit in the pipes and cool off.  What a waste of energy.
 
I'm looking at installing one of those small tank 120V heaters to put under the kitchen sink.  Doing dishes rarely uses more than a gallon of hot water anyway.  99% of the time, the convenience of having instant hot water would outway the inconvenince of only having a limited amount available.

Now that I've seen places with this type of heater (the small, by location type) I completely agree.  Plus, there's always the laziness issue that it's nice not to have to wait to get that hot water.

dmbaer

RobertB

Even in an extremely large home, at worst, you will waste a quart of unheated water.

My home certainly isn't huge ... ~2000sq. ft.  The kitchen sink is at one end of the house and the water heater at the other.  I have to run close to 1.5 gallons of water before the water coming out the tap is actually hot.  But the worst part is that when done washing dishes, or whatever, I've heated close to 1.5 gallons of water that will just sit in the pipes and cool off.  What a waste of energy.
 
I'm looking at installing one of those small tank 120V heaters to put under the kitchen sink.  Doing dishes rarely uses more than a gallon of hot water anyway.  99% of the time, the convenience of having instant hot water would outway the inconvenince of only having a limited amount available.

True enough.
I thought about that after I wrote it. That's what I get for trying to think after a 15 hour day.
Depending on how the house is plumbed (size of pipe/length of runs) there is a variable on how much water has to be purged before hot water gets to the point of use.

Kalle Rantaaho

Jeff Evans


I am assuming then you guys don't have gas as well as electricity. The ultimate way to go is a gas heater that only turns on when you need the water and it heats it on the go. You never run out then. But this is only good of course where gas is available. 

How many gallons of hot water per minute can those systems nowadays  produce? I've seen such long ago (in the UK) but the ones I saw were tiny ones - one unit for the bathub, one for kitchen etc. and they were ridicilously inefficient. It took an hour to fill the bathub, and then the water had already cooled down.
 
How reliable are they in the long run nowadays? I remember reading about the amount of maintenance they require and how dangerous they can be in case of failure.
LATE ADDITION: I've never seen one in Finland, and we have a rather cold climate. So I assume there's a reason no-one uses those here.

Kalle, we have one unit which services the whole house, including taps, shower/bath & central heating.

As long as they are serviced regularly the modern units rarely suffer from failure, and the entire family can take back to back showers with absolutely no temperature roll-off.

yes, - not the rust itself but the reason for the rust, which would be a leak causing the rust.  water is conductive.  that much rust means there's a fairly significant leak which could cause an electrical fire.

disclaimer:  I'm not an electrician nor a plumber.  But I would not want to continue to use that system in my house until I got it fixed.

Janet





My son sent me this picture of the water heater the other day...he'd like to know if he needs to be concerned about the rust.  I figured someone here could tell us. :)

It's looking pretty ragged, I'd say replace it beofore it starts leaking.

Beagle

djwayne

Janet





My son sent me this picture of the water heater the other day...he'd like to know if he needs to be concerned about the rust.  I figured someone here could tell us. :)

It's looking pretty ragged, I'd say replace it beofore it starts leaking.

where did the rust come from if not from a leak?

The rust can come from age, heat, and moisture... likely a combination of all 3. If the rust is dry surface rust, it's probably OK. Surface rust on sheet metal is no big deal. There looks to be some surface rust on the tank but not much... most of it looks to be on the sheet metal for the thermostat. 


The terminal screws appear to be rusted a bit and the wire looks to be secured improperly. The electrical connection should be clean and have no corrosion or rust on it. Corrosion and rust impede the flow of current and will cause heat that will burn the terminal screws off and damage the copper wire. Turn off the power and clean them up with a soft wire brush. Wrap the wire tightly and secure the screws firmly but not overly tight. 


The most concerning thing to me is the white powdery stuff around the heating element. It looks like there is or has been a leak and the minerals have deposited there and below the element. If it is leaking and allowing minerals to deposit, that needs to be resolved. 


If you go to the effort to remove the elements to clean up that corrosion, and the heater is in good condition other than that, I'd place new heating elements in it. 


I'm not a plumber although I have worked on and replaced the elements in more than my share of water heaters.... a water heater is expected to live about 10 years...give or take.  With proper maintenance , it can go much longer than that. Flush them out periodically, and the heating elements on the bottom will last longer.  I've seen some that are 15 years old and inside  the covers look as new as the day they were installed. It depends on the environment where they were installed. Most that are installed inside a house stay pristine. Garages, basements, utility rooms have higher temp variations and humidity and rust is common in those. 

If it springs a leak you may get more than a puddle, it could start raining in your house !! If it's more than 7 years old, I'd replace it, as it looks like it could start leaking anytime. A small leak can turn into a big spray in no time. You can replace heating elements and temperature controls, but once the tank springs a leak, it has to be replaced. It all depends on how big of a mess you want, it also could start spraying at a very inconvient time. So it's better to replace it BEFORE an emergency situation occurs.

I agree.

Well it's not that bad...you can get a new tank at Lowe's or Home Depot for under $300. Any home remodeler worth his salt can replace it for you fairly reasonable.

Oh, I know it's not that bad.  (the cumulative effect of a little something every month gets me though..)  Anyway, it seemed like the ones we looked at last week were either $249 or $549--no in-between, and I didn't take the time to figure out the difference (well, I couldn't tell by what they said on the side.)  I had no idea there were so many choices, having never shopped for one in my life.  :)  

Yep.  And then there's the landscaping. 

By hand. 

Hot...for sure!