[DriveElectric]

I currently have an old gas water heater in my house. I am considering replacing it with this type of electric water heater.
link

There is no holding tank constantly heating water. This type of water heater only turns on when hot water is demanded somewhere in the house. So there will only be bursts of energy demand to heat water. I have always thought that heating water with natural gas all night and all day is a waste of energy.

Does anyone have any experience with this type of water heater? Features of the PowerStar Electric Instant Hot Water Heaters
95% efficiency rating – maximum efficiency
Solid copper heat exchanger
Electronic flow switch
3/4" brass NPT fittings
External temperature control knob
Activation rates of .6 gallons per minute (AE 115) and .8 gpm (AE 125)
Filter screen on inlet
Thermal cut-out for safety
No temperature/pressure relief valve necessary (check local codes)
Flow sensor to provide a constant output temperature
10 year warranty
No standby heat loss... saves on energy
Mounts almost anywhere Saves installation costs

[rerere]

$this->bbcode_second_pass_quote('DriveElectric', 'I') currently have an old gas water heater in my house. I am considering replacing it with this type of electric water heater.

[aahala]

You may want to change to a tankless system for some of the advantages
you listed.

Energy loss due to a tank should be well down on your reasons for
changing. It doesn't amount to that much, maybe 10% or less
of water heating costs. The temperature and amount of hot water one
uses is much more important.

[Dvanharn]

Americans waste a tremendous amount of hot water. That's why we can sell active solar hot water systems with two to three 4' x 10' flat plate thermal collectors and a 120 gallon solar storage tank in this country to individual families - for $5,00 to $6,00 installed!

If you have natural gas or propane on the property, they are still less expensive for heating of all types, including hot water. The ad for the electric tankless heaters at the beginning of this post don't mention that a 6 gpm electric tankless water heater requires two (yes, double runs) 40 amp, 240vac circuits, and the 8 gpm model requires three 40 amp circuits. (That's five big fat eight gauge wires from your main distribution/circuit breaker box for the 6 gpm model and seven of those wires for the 8gpm model.

If your current water heater is in good working condition (do drain it a bit to remove the sediment every year), set it at 125 degrees F, and add an aftermarket external "blanket" to conserve energy.

If I owned a house, and it needed a new water heater, I would install a gas or propane tankless type. I might also install a modest solar hot water system with "oversized" hot water storage. If you "oversize" hot solar storage and keep the average maximum temp below 140 degrees F, it will minimize losses and provide lots of usable hot water. Without solar, a simple Many people want to get the stored water as hot as possible, but the "standby losses" increase tremendously as water temperature rises.

The losses in stored and piped very hot water is also a reason why evacuated tube collectors are not as good as black-chrome coated flat plate collectors for everyday domestic hot water applications. Evacuated tubes are good if high water temperatures are required, but it's often a better idea to preheat water going to boilers with flat plate collectors and finish the temp rise with gas. Plus, in cold climates, ice and snow will not easily melt off of evacuated tube collectors, but will slide off flat plate collectors if they are mounted at a pitch of 30 degrees or steeper.

Dave van Harn

(I currently work part-time for Alternative Power Systems in Sebastopol, CA as their solar thermal specialist. For 3 years prior to that, I did inside sales and dealer development for Heliodyne of Richmond, California, now the oldest solar heating manufacturer in the U.S.

[Dvanharn]

Americans waste a tremendous amount of hot water. That's why we can sell active solar hot water systems with two to three 4' x 10' flat plate thermal collectors and a 120 gallon solar storage tank in this country to individual families - for $5,00 to $6,00 installed!

If you have natural gas or propane on the property, they are still less expensive for heating of all types, including hot water. The ad for the electric tankless heaters at the beginning of this post don't mention that a 6 gpm electric tankless water heater requires two (yes, double runs) 40 amp, 240vac circuits, and the 8 gpm model requires three 40 amp circuits. (That's five big fat eight gauge wires from your main distribution/circuit breaker box for the 6 gpm model and seven of those wires for the 8gpm model.

If your current water heater is in good working condition (do drain it a bit to remove the sediment every year), set it at 125 degrees F, and add an aftermarket external "blanket" to conserve energy.

If I owned a house, and it needed a new water heater, I would install a gas or propane tankless type. I might also install a modest solar hot water system with "oversized" hot water storage. If you "oversize" hot solar storage and keep the average maximum temp below 140 degrees F, it will minimize losses and provide lots of usable hot water. Without solar, a simple Many people want to get the stored water as hot as possible, but the "standby losses" increase tremendously as water temperature rises.

The losses in stored and piped very hot water is also a reason why evacuated tube collectors are not as good as black-chrome coated flat plate collectors for everyday domestic hot water applications. Evacuated tubes are good if high water temperatures are required, but it's often a better idea to preheat water going to boilers with flat plate collectors and finish the temp rise with gas. Plus, in cold climates, ice and snow will not easily melt off of evacuated tube collectors, but will slide off flat plate collectors if they are mounted at a pitch of 30 degrees or steeper.

Dave van Harn

(I currently work part-time for Alternative Power Systems in Sebastopol, CA as their solar thermal specialist. For 3 years prior to that, I did inside sales and dealer development for Heliodyne of Richmond, California, now the oldest solar heating manufacturer in the U.S.

[PlannerBee]

I have to replace a hot water heater soon. Anyone here have any experience with them?

[Devil]

If you are in a frost-free area, (night-time temps never below -3°C), you can install a direct hot-water solar system. The cost is <$500 and the payback time is <2 years. 96% of the houses here have them and they work fine with hot water for about 340 days/year (we have an immersion heater for topping up on cloudy winter days). The panel size is ~ 1½ m².

If you have frosts, then you need an indirect system which is less efficient and more costly, requiring a heat exchanger. I think you're now looking at a ~6-8 years payback time and you need ~3 m² of panels (possibly more in northern latitudes).

[BiGG]

I have an on-demand system linked here that works great and will never return to the antiquated tank style again. These things save lots of money no matter how you look at it!

This page shows lots of media coverage from Home & Garden Television, The Wall Street Journal, The Discovery Channel, Boeing, NASA etc. and is well worth looking through.

Product details here showing sizing & climate information.

[pea-jay]

Here is a question. I live in a part of CA that occasionally frosts (as low as -5C) every few years. For the most part, winter is a useless from a solar collection stand point anyways, since my valley is plagued with prolonged foggy and cloudy periods that cut solar insolation to pathetically low levels. From November to March we literally do not see much sun (one winter we were fogged in for 20 consecutive days).

My question is, can I get a direct system, drain it completely and not worry about frost/freeze conditions or does the collection assembly always have some water in it? I'd plan on using it from the beginning of March to the end of October and using gas the rest of the time.

[ubercrap]

I've heard that often the on demand systems are often being installed for pseudo-luxury reasons, supplementing regular hot water heating systems by heating the water right at the sink/tub because the house is so big/room so far away from the hot water heater and people don't want to wait a few seconds for the hot water to come out.

[Devil]

$this->bbcode_second_pass_quote('pea-jay', 'H')ere is a question. I live in a part of CA that occasionally frosts (as low as -5C) every few years. For the most part, winter is a useless from a solar collection stand point anyways, since my valley is plagued with prolonged foggy and cloudy periods that cut solar insolation to pathetically low levels. From November to March we literally do not see much sun (one winter we were fogged in for 20 consecutive days).

My question is, can I get a direct system, drain it completely and not worry about frost/freeze conditions or does the collection assembly always have some water in it? I'd plan on using it from the beginning of March to the end of October and using gas the rest of the time.

[SolarDave]

We had a Bosch - with the battery ignition. Worked as advertised.

Startup water was colder and took longer to arrive, because there was no warm water in the system at all. Once the water arrived, it was limitless. Our hot water bill declined by one third.

The batteries had to be replaced once a year and the incoming water screen/filter cleaned out once a year.

[NonToxic]

The NG models work well. Takagi has been a good performer for my brother. If your electric I might suggest one of the smart water tanks from ge. The tankless electric models take a lot of amps (100?)

[strider3700]

Ok I'm now eyeing up my electric hotwater tank as being the next offensive in my on going war against the electric bill.

My plans for the following year include

move the tank - this is needed to gain space in it's current location not for efficiency

Build a inulated box around the tank - basically I'm thinking 3 inches of foam in a box around the tank(with an access door) I'll then stuff the rest of the space with loose pink insulation

add heat traps to the plumbing - I have to do the plumbing when moving the tank so might as well. Apparently they stop the hot water from circulating out into the pipes when water isn't running.

insulate all of the pipes - cheap, easy and I don't have much to do thanks to a fairly efficient layout.

add a timer to the heater- basically I want to turn it on in the mornings off dduring the day on in the evening off at night during weekdays. Then turn it back on all day during weekends

add solar heating - a nice project to build a collector and heat exchanger this winter, we'll see.

Now my question is about the timer. I've had a hell of a time finding any timer for hot water tanks, and the one I found was ultra industrial looking, definitely not what I had in mind. I was looking for something more like a programmable furnace thermostat. Can anyone point me to one?

I have a 220V programmable thermostat at home. Could one of those be used? I'm assuming the issue is the amperage the water tank draws is probably much higher then the thermostat can handle spliced directly in.

What about using a relay and a thermostat? 220V relays can't be that uncommon are they?

Any other suggestions?

[Seadragon]

I've found timers readily available in the US at Home Depot or Lowe's. They are sort of crude looking, not like HVAC thermostats, but the one I had ran perfectly for 5+ years. Not sure what your sources are in Vancouver...

[aflurry]

I don't want to high-jack this thread, but in your research did you check into the relative cost/efficiency of in-line, or on-demand water heater units, as opposed to tank based ones?

http://www.plumbingsupply.com/index-tan ... aters.html

While I was travelling in Europe I noticed they used these almost exclusively. I haven't looked into it far enough, but they seem to have no down-side.

I guess there is a flow rate issue, but in the ones I used the water was so hot I had to turn on the cold pretty strong to cool it down.

smaller unit size, scalding hot water, no running out of hot water, no keeping 40 gallons of hot water for days at a time when you aren't using it.

can't understand why these aren't in wider us in the US. Regulations? What?

[strider3700]

I did a little bit of research but what I was finding was whole house electric instant on heaters draw a crap load of power all at once and that made for some heavy duty wiring requirements that my older wiring system would need a fair amount of work to make work.

I'll walk through that page some more. I don't use much hot water so one of the smaller units may work out better for me and save me the issue of needing to move the water tank to save space. I would be giving up on solar heating of water though.

[PeakOiler]

$this->bbcode_second_pass_quote('aflurry', 'I') don't want to high-jack this thread, but in your research did you check into the relative cost/efficiency of in-line, or on-demand water heater units, as opposed to tank based ones?

http://www.plumbingsupply.com/index-tan ... aters.html

While I was travelling in Europe I noticed they used these almost exclusively. I haven't looked into it far enough, but they seem to have no down-side.

I guess there is a flow rate issue, but in the ones I used the water was so hot I had to turn on the cold pretty strong to cool it down.

smaller unit size, scalding hot water, no running out of hot water, no keeping 40 gallons of hot water for days at a time when you aren't using it.

can't understand why these aren't in wider us in the US. Regulations? What?

[MonteQuest]

$this->bbcode_second_pass_quote('strider3700', ' ')Now my question is about the timer. I've had a hell of a time finding any timer for hot water tanks, and the one I found was ultra industrial looking, definitely not what I had in mind. I was looking for something more like a programmable furnace thermostat. Can anyone point me to one?

[strider3700]

$this->bbcode_second_pass_quote('PeakOiler', '
')
I learned that if the water one's heating is very hard, the heating elements of tankless water heaters have a shorter lifetime. (This is true of conventional electric water heaters as well.) Can any readers confirm this from their experience?

Strider, if I were you, I would make the solar water heater your top priority and add the timer afterwards if you think you would still need it.