# Domestic Hot Water.



## Enzo's Dad (Jan 20, 2014)

Ok now that i am using a stove to heat the house, I am beginning to realize how much a hot shower costs me. Between the baseboard heat, and domestic hot water if figure I am going through 15-20 gallons of oil a week. Id say 50% of the oil consumption is for hot water. I"m in the camp that home heating oil will continue to go up and I have propane for a gas cooktop. Will I save money by switching to a propane hot water heater, or do i have spend several $1000's and switch to a rennai system to save money in the long run?

Im sure this idea has been discussed but i am looking for ideas.


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## Dakotas Dad (Jan 20, 2014)

A tankless is not for everybody. There is a lot more to consider than operating costs with them, although you won't ever hear that from a salesperson. I know 3 families here who have put them in, not a one says they would do it again. Among other things, we have really hard water, and they scale up just like any other water heater. Oil, electricity,  or propane, you are captive to a supplier. 

Which, historically is the cheapest and/or most reliable in your area? That is about all the criteria I can think of to base the decision on. Can you reduce the amount of baseboard heat the house is calling for? Electric WH's can be put on timers so they don't maintain hot water all day when nobody is home, can that be done with oil, and/or would it work for your lifestyle?


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## firefighterjake (Jan 20, 2014)

Dakotas Dad said:


> A tankless is not for everybody. There is a lot more to consider than operating costs with them, although you won't ever hear that from a salesperson. I know 3 families here who have put them in, not a one says they would do it again. Among other things, we have really hard water, and they scale up just like any other water heater. Oil, electricity,  or propane, you are captive to a supplier.
> 
> Which, historically is the cheapest and/or most reliable in your area? That is about all the criteria I can think of to base the decision on. Can you reduce the amount of baseboard heat the house is calling for? Electric WH's can be put on timers so they don't maintain hot water all day when nobody is home, can that be done with oil, and/or would it work for your lifestyle?



Would love if you could elaborate some more on the tankless hot water heaters DD . . . we are going through maybe 3 gallons each week of propane which is only used for cooking and hot water (conventional heating tank with power vent). I've thought some about switching to a wall mounted on-demand unit to save on propane usage/expense.

I should mention that we do have hard water, but so far that doesn't seem to be a real issue with the conventional heating system.


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## velvetfoot (Jan 20, 2014)

We put in an inexpensive electric water heater instead of the oil indirect.  If you're using an indirect and heating with oil during the winter, it might pay to run the indirect in winter and electric in summer.


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## Enzo's Dad (Jan 20, 2014)

3 gallons of propane sounds good to me! Im thinking about having a second heating system for hot water.
And for the record we are in a household of 3


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## DougA (Jan 20, 2014)

If I were doing it all over, I would put in a very small (5 gallon) electric WH in th ebathroom and one supplying the kitchen/washing machine.  Most clothes can now be cleaned in cold water but there are many people saying you need to clean underwear, etc, in hot water because soap alone will not clean the germs in underwear.  If you are using a brief shower instead of a bath tub, 5 gal. is plenty. I know that we waste a lot of hot water because the WH is farther from the kitchen than it should be.


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## johnny1720 (Jan 20, 2014)

I have had a tankless for about 6 years and I love it.  Before I preheated my water with my heat pump I was using 180 gallons of propane per year.  Now I am using about 120 gallons of propane per year.  That being said if this thing stops working I will turn the breaker on for my electric backup. An electric hot water tank is $350.  A tankless setup is $1400 but about 1/3 less to operate than an electric.

The propane company charged me $3.59 for 80 gallons last fall because I don't use enough propane.  Because of this I will probably switch to electric next time around


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## woodgeek (Jan 21, 2014)

When I had an oil boiler that I was just using for DHW I was burning ~1 gal/day of HHO ($1000/yr), but >75% was standby losses !  In fact, I was paying twice in the summer, b/c half my AC load was the parasitic losses from the boiler.  

Bottom line, any fuel in a DHW system with lower losses will be cheaper to run.  A conventional electric tank will be cheap to install, have maybe 5-10% parasitic losses, and would cost $500-$700 a year to run, with no 'maintenance'.  I would get (and in fact I did) get a Heat Pump Water Heater, HPWH.  which costs me ~$200/yr to operate with a fam of 4, you might be $300/yr with more expensive elec.  Upfront is a little higher, but many utilities have rebates.  The fed rebate for HPWH (I think) expired in 2013, but you might check to see if it was renewed.

Lots of threads in here about switching from oil DHW to HPWH, pretty much free money, if you search.  One issue is to check that you can shut down the oil boiler in the summer and leave it cold.  Prob 90% of old boiler are aok with this, 10% might have small leaks.  IF you can't shut it down in the summer, you are stuck, and no new DHW heater will get the oil monkey off your back.


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## Highbeam (Jan 21, 2014)

If they could only make the HPWH quiet. From teh specs, it is much louder than the refrigerators.


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## woodgeek (Jan 21, 2014)

Mine is a 7' tall monster, and it is louder than a refrig, but quieter than an AC window unit.  In bedroom, not ok, in garage, aok.


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## velvetfoot (Jan 21, 2014)

Garage?  These things seem better suited to the warmer climates.


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## woodgeek (Jan 21, 2014)

velvetfoot said:


> Garage?  These things seem better suited to the warmer climates.



attached garage tucked under....insulated, seldom goes below 50°F.


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## maple1 (Jan 22, 2014)

The 80gallon electric I got last year: $300 to buy & $30/mo. to operate.


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## jebatty (Jan 23, 2014)

A reminder: a regular resistance electric hw heater, super insulated, pipes insulated, and effective heat traps on both the cold and hot water ports, can be very efficient. By super insulation I mean at least 6" of fiberglass or similar, sealed for air leaks, on the top, around the sides, and underneath, plus the hw htr raised off the cold floor. I did this for our electric hw heater years ago, hw heater on a separate meter, and electric usage dropped 50%. Our electric bill for hot water is about $4.00/month, maybe $5.00 if we have lots of family visiting during a month. 

And I second 





> If I were doing it all over, I would put in a very small (5 gallon) electric WH in the bathroom and one supplying the kitchen/washing machine.


 Our kitchen is a long way from our main electric hot water heater, and I disconnected the supply to the kitchen and dishwasher from the main supply and put in a separate 5 gallon heater just for the kitchen, super insulated as above. Now immediate hot water, and no longer does anyone let the hot water run continuously while washing/rinsing dishes. Turn it on and turn it off. No waste, plenty of hot water.


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## ironpony (Jan 23, 2014)

my personal choice electric.


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## maple1 (Jan 23, 2014)

Might as well talk both ends of the specturm - tankless coil in an oil boiler has to be the absolute worst.


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## Enzo's Dad (Jan 23, 2014)

maple1 said:


> Might as well talk both ends of the specturm - tankless coil in an oil boiler has to be the absolute worst.


 
Thats what I have, I hate it this summer I am going to change. Leaning twoard a propane 60 gallon. I was just seeing what others had done.


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## woodgeek (Jan 23, 2014)

Enzo's Dad said:


> Thats what I have, I hate it this summer I am going to change. Leaning twoard a propane 60 gallon. I was just seeing what others had done.



NG and Propane tank heaters are also low eff due to flue losses, and propane can be higher $/BTU than oil.  Might want to compute a cost of operation using your local cost for propane and kWh.  My guess is that HPWH will be cheaper to operate than propane in your area...if you have a basement spot for it.


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## Circus (Jan 23, 2014)

I'm not suggesting solar but thought someone should mention it.

For five years I've had a 80 sq. ft hydronic solar collector, siphon feed, tank/exchanger, propylene glycol system that supplies all my hot water for 9 months a year. The roof that the collector is mounted to is too shallow for reliable hot water from Dec through Feb so it feeds 80 or 90 degree water to a electric water heater. The rest of the year the electric water heater is turned off and stores excess hot water from the solar tank/exchanger.
Glad I built my system but it could be a royal pain if you don't know what your doing.

As to which type, LP or Electric, is best. For low consumption electric is best because of low standby loses. For high consumption gas is best because of lower fuel cost.


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## Highbeam (Jan 23, 2014)

I have an old resitance tank heater buried in a built in cabinet that surely is half full of mud from our well. I plan to replace it for several reasons and will most likely use a marathon tank heater. This company does all of the super insulation for you plus the tanks are plastic so they are supposed to last forever or at least until the market allows technology to produce a heat pump water heater that does not pollute my home with noise or cold air.

The super insulated tank heater simply eliminates the stand by loss. You still need to pay for the electrons to raise the temp from 50-120 at least once.


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## Highbeam (Jan 23, 2014)

Circus said:


> . For high consumption gas is best because of lower fuel cost.


 
This is certainly not true in my location. Propane at 2$ per gallon doesn't beat electric at 10 cents per kwh. Perhaps you meant piped natural gas like in the city?.


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## Enzo's Dad (Jan 23, 2014)

I hate my boiler running in the summer, however i started reading about Indirect water heaters tied to the boiler, This may be the best use of money.
Electricity is expensive in ct Right now we are at 18 cents per kilowatt.


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## woodgeek (Jan 23, 2014)

Enzo's Dad said:


> I hate my boiler running in the summer, however i started reading about Indirect water heaters tied to the boiler, This may be the best use of money.
> Electricity is expensive in ct Right now we are at 18 cents per kilowatt.



Unless you have a cold-start, low mass boiler (unlikely if you have a DHW coil), then an indirect will do little to reduce your bill.  And I was figuring you for 18 cents/kWh on the HPWH heater expense.


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## dougstove (Jan 24, 2014)

+1 on solar domestic hotwater.
I heat the house with a woodstove.
We get all our hotwater from the solar panel ('Thermodynamic') for ~7 months a year, and a substantial boost for 2-3 more.
In Connecticut you would do even better.
We put the water tank in the basement so the waste heat warms the basement, which is beneficial all year in my climate.


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## peakbagger (Jan 25, 2014)

Many experts are shifting away from recommending solar hot water panels. The current consensus is to install a heat pump hot water heater and some solar panels set up with net metering.  If you do want to look at SHW, you need to look at evacuated tubes versus conventional flat plate. Flat plates at best raise the water temp 70 degrees which if you have well water at 40 degrees yields 110 deg hot water. Evac tubes are far more expensive but they can boost water 140 degrees so 40 degree well water yields 180 degree water so they can cover you in the winter unless you get a stretch of cloudy weather.


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## Circus (Jan 25, 2014)

peakbagger said:


> Many experts are shifting away from recommending solar hot water panels. The current consensus is to install a heat pump hot water heater and some solar panels set up with net metering. .


No authority has say over solar thermal. Getting the OK for a grid tie PV is becoming a nightmare. Not to mention the cost.


			
				peakbagger said:
			
		

> If you do want to look at SHW, you need to look at evacuated tubes versus conventional flat plate. .


We get at least one hail storm per year and they don't make tempered glass or polycabonate evacuated tubes.


			
				peakbagger said:
			
		

> Flat plates at best raise the water temp 70 degrees. Evac tubes are far more expensive but they can boost water 140 degrees so they can cover you in the winter.


The costs of boosting water temperature for 3 months from a flat panel is trivial.
Top performance isn't everything. DIY flat panel based systems sheds snow, cheap, tough, no monitoring needed and seldom need repair.


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## woodgeek (Jan 25, 2014)

Enzo's Dad said:


> I hate my boiler running in the summer, however i started reading about Indirect water heaters tied to the boiler, This may be the best use of money.



Again, I think that 90% of indirects on oil boilers *increase* standby losses, which are currently prob 75% of your operating costs.  I wouldn't trust your oil company or techs to give reliable info on this.  The exception would be if you had a very fancy modcon boiler, which do not seem very common in the US; nice tech but expensive fuel.

This 'standby' thing is not well understood or appreciated.  In the summer, your DHW is not what is driving your oil usage.  I put a timer on my boiler, and was using about 1.3 gallon of oil per day.  When I went on vacation (no DHW), the boiler still used 1.1 gallons/day!!  Its a double whammy...not only is oil a really expensive fuel, but you are wasting 3 gallons for every gallon you use to heat water.

Even at 18 cents, a properly insulated (2" foam) electric tank heater, and shutting down the boiler in the summer will likely reduce your DHW costs from >$1000/yr to more like $500-600.  While 18 cent elec is maybe 70-100% more $ per BTU than oil, the low standby makes it cheaper.

A HPWH like the geospring will cost maybe $500 more than a conventional tank at purchase (less whatever rebates you can find), but will cost half as much as the conventional electric to operate, prob less than $300/yr.

Commercial solar DHW can easily run $5-10k installed, and will have an operating cost not much better than the HPWH (on the East Coast), like $200-300/yr, for conventional electric backup in the winter.  I can't see why anyone would choose that over a HPWH.


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## woodgeek (Jan 25, 2014)

Circus said:


> No authority has say over solar thermal. Getting the OK for a grid tie PV is becoming a nightmare. Not to mention the cost.
> 
> We get at least one hail storm per year and they don't make tempered glass or polycabonate evacuated tubes.
> 
> ...



Um.  The OP didn't say anything about spending thousands on solar, thermal or PV.


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## velvetfoot (Jan 25, 2014)

My cold start boiler was going cold for long stretches during the winter, (note, I said WAS, as in last winter), and so, it would have similar wasteage to the summertime.  I figured the cheap water heater was worth a shot.  If my utility dangled a big rebate, then I'd think about a hpwh more I guess.  I've insulated the walls in my basement and the joists already had insulation, so I am not sure how the thing would work down there.


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## Enzo's Dad (Jan 25, 2014)

velvetfoot said:


> My cold start boiler was going cold for long stretches during the winter, (note, I said WAS, as in last winter), and so, it would have similar wasteage to the summertime.  I figured the cheap water heater was worth a shot.  If my utility dangled a big rebate, then I'd think about a hpwh more I guess.  I've insulated the walls in my basement and the joists already had insulation, so I am not sure how the thing would work down there.


 
I have spray foam in the basement and its finished, so i am not sold on the HPWH yet.


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## woodgeek (Jan 25, 2014)

how big is the boiler room?


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## Enzo's Dad (Jan 25, 2014)

woodgeek said:


> how big is the boiler room?


 
I really need to take pictures of that. the guy that built the house had the concrete pored so that there is a room under the back porch. 4 ft by 20ft


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## Circus (Jan 25, 2014)

woodgeek said:


> Um. The OP didn't say anything about spending thousands on solar, thermal or PV.


 


Circus said:


> I'm not suggesting solar but thought someone should mention it.


 
Enzo's Dad needs to shut down the oil fired boiler in non heating seasons. Any other water heating scheme is preferable.


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## Enzo's Dad (Jan 25, 2014)

Circus said:


> Enzo's Dad needs to shut down the oil fired boiler in non heating seasons. Any other water heating scheme is preferable.


 
Thats my thought, just need to figure out the best alterative. On paper solar and hphw look good, but i would be 8 years before i would recoup the cost.....if money were no object i would go geo thermal


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## Dave A. (Jan 25, 2014)

Trying to follow this discussion about indirect DHW with oil boiler, and it sounds like some may be conflating indirect with tankless coil.  They are two different systems. Indirect oil systems usually use a small well insulated 2" foam SS tank on a separate priority zone.  The boiler fires to circulate water in the coils in the tank in the non-heating seasons only when the water temp in the insulated tank drops, mostly only when HW is used.  If no HW is used the boiler eventually cools to room temp with a cold start boiler set up.

With tankless coil, the boiler is maintained to appx 160F year round and fires to maintain temp from standby losses in the boiler and when HW is used.  With this type of system an electric resistance DHW tank may save energy in the summer vs. the tankless coil.

With indirect, if the boiler is efficient, there's generally no savings with a separate electric resistance DHW tank in the summer, though HPWH might be different.

Still according to this http://energy.gov/energysaver/articles/tankless-coil-and-indirect-water-heaters

With a cold start efficient boiler, indirect may be the least expensive option.


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## velvetfoot (Jan 25, 2014)

Dave A. said:


> the boiler eventually cools to room temp


Metal and circulating warm up, then cool down, stack loss.  It adds up.


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## Enzo's Dad (Jan 25, 2014)

velvetfoot said:


> Metal and circulating warm up, then cool down, stack loss.  It adds up.


 
My last two houses had an indirect hot water heater. Looked just like the diagram on the energy .gov web site This is a coil, the minute I start a shower the boiler kicks on . and if multiple zones are calling for heat ..good luck getting any hot water.  It would be 899 plus install for this system


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## velvetfoot (Jan 25, 2014)

You can set the water heater as a priority zone, so that it gets satisfied first.


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## boomhour (Jan 25, 2014)

Not sure if any have come across this water heater , suppose to come on line in May

http://www.kickstarter.com/projects/1132758406/heatworks-model-1-your-next-water-heater


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## woodgeek (Jan 25, 2014)

Can the oil boiler be set up to be cold-start?  Make, model and year?


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## Clarkbug (Jan 26, 2014)

boomhour said:


> Not sure if any have come across this water heater , suppose to come on line in May
> 
> http://www.kickstarter.com/projects/1132758406/heatworks-model-1-your-next-water-heater



First I have seen it, thanks for sharing!

Interesting idea, but Im not sure how I feel about the "heats via the resistance in water".  I could see issues if you had really pure water without any "stuff" in it to create resistance.  I also think that unless you hook it to a 220 30 amp breaker, you wont get the full output, which will make some people grouchy if they think they will get the same results with a 120v 15A circuit.  (Not people here, but general buyers).

I would like to see one in action once they hit the market.


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## Highbeam (Jan 26, 2014)

boomhour said:


> Not sure if any have come across this water heater , suppose to come on line in May
> 
> http://www.kickstarter.com/projects/1132758406/heatworks-model-1-your-next-water-heater



That is nothing more than an on demand electric wat e r heat e r. A wall kettle. Don't be fooled.


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## woodgeek (Jan 26, 2014)

boomhour said:


> Not sure if any have come across this water heater , suppose to come on line in May
> 
> http://www.kickstarter.com/projects/1132758406/heatworks-model-1-your-next-water-heater



I'm pretty skeptical that those graphite electrodes will 'never plate up or rust' and will last 'forever'.


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## Seasoned Oak (Jan 26, 2014)

I have a 30 Gallon electric water heater with 5 people on it for the last 20 years. I dont even notice a change on my light bill as i switch from boiler hot water to electric in summer. I  imagine  the 30 Gal is only using as much as the fan and motor on the boiler so its a wash.


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## boomhour (Jan 26, 2014)

Clarkbug said:


> First I have seen it, thanks for sharing!
> 
> Interesting idea, but I'm not sure how I feel about the "heats via the resistance in water".  I could see issues if you had really pure water without any "stuff" in it to create resistance.  I also think that unless you hook it to a 220 30-amp breaker, you won't get the full output, which will make some people grouchy if they think they will get the same results with a 120v 15A circuit.  (Not people here, but general buyers).
> 
> I would like to see one in action once they hit the market.



I, too, have some reservations on its performance capabilities.  My well water is about 49 F and I would think it would be using most of that 30-amp breaker at shower time. But the 120v 15A heater would do well in the R V and boat market would be at the top of the list for my boat.  The 15 amp model could be used in small business.  i.e filling hot tubs, pressure washer, etc.  I hope to see it on line soon. I wonder if Home Depot would pick something like this up?


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## Highbeam (Jan 27, 2014)

boomhour said:


> I, too, have some reservations on its performance capabilities.  My well water is about 49 F and I would think it would be using most of that 30-amp breaker at shower time. But the 120v 15A heater would do well in the R V and boat market would be at the top of the list for my boat.  The 15 amp model could be used in small business.  i.e filling hot tubs, pressure washer, etc.  I hope to see it on line soon. I wonder if Home Depot would pick something like this up?



Seriously? They do. On demand electric water heaters of many wattages and voltages have been available for many years.


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## boomhour (Jan 27, 2014)

Yes they have, and I have looked into them about 5 years ago, but were not recommended for my area . We have a heavy snow cover right now and my water temp is up, has been as low 44 F.  Seriously.


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