Is it time to switch my hot water to electric and leave indirect oil hot water?

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Old 02-25-14, 08:45 AM
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Is it time to switch my hot water to electric and leave indirect oil hot water?

Over the past four years I have used 120 gallons of oil for oil indirect hot water, from mid-May to mid-Sept, as per oil tank fills (fill up in mid-May and mid Sept). That is @$4.50 a gallon current prices to be $540 or $135 a month figuring 30 gallons a month or one gallon a day of oil for hot water for a family of four. Recently a friend converted to natural gas and gave me a six month old high efficiency electric hot water heater. I have sketched out an installation where I can either go all electric with hot water, or stay with oil indirect hot water Mega-stor, or use the electric hot water heater to temper (set temp to say 100 degrees) incoming well water and then put that into the indirect tank.
My goal is saving money.

I know the hot water costs when heat is off. When heat is on, I do not. I have heard the argument that cooking a hot dog over a fire does not take away the heat from the fire and this is the same thing with winter indirect hot water. No one can tell me how much indirect hot water costs with a Peerless boiler during the winter. I can’t see exactly why it would be less than the summer but let’s say it is. Would I be using .5 gallon then a day for hot water? Who knows?

Every time a mouse farts in Nigeria or Venezuela, oil goes up. I think it will be $5 next season. If I am using 120 gallons of oil for hot water over four months and I extend that to 12 months, it may be 360 gallons for hot water and another 300 gallons for heat (we use a woodstove to help heat the house so annually we are using about 660 gallons of oil). I know everyone says “more BTUs in oil than electric” but I am looking at costs. I have .079 kwh locked in for 1.5 years and a delivery rate around .10 so figure .18 an hour. The electric hot water heater label says the unit uses 4260 kwh but I am using 5000 as a baseline. 5000 x .18 = $900 estimate or $75 a month. If I switch to electric hot water, am I saving money? I think I could to the tune of $60 a month. My concerns are turning off the Peerless boiler for five months (leak potential when things cool down?) and the indirect tank coil corroding inside (yes we have a water softener and yes I know I should drain the tank if not in use) so that is why I am thinking of running the electric hot water heater to temper water into the indirect hot water tank during May through September and leaving the boiler on. If the boiler is off for five months, it is not using oil and that is attractive.

If I use electric hot water all year, I may be getting off the oil tit for 260-360 gallons and I can spread the electric costs monthly onto a budget plan instead of spending $1100 to $1600 for a tank and a quarter of oil at once. If oil goes up, my hot water costs stay relatively stable. I have plenty of wood, cut and split it myself, and if I can get oil for heat being the only oil then 300 gallons for oil even at $5 a gallon is doable.

Recommendations? Stay with indirect oil hot water? Turn off the boiler for four-five months and there won’t be leaks? Drain the indirect tank during the summer? Or leave it full and temper incoming water via the electric hot water tank? Stay with indirect oil hot water during the winter? Shut off indirect oil hot water for the year? Has electric hot water cost tipped against oil hot water cost so it is now cheaper? I am trying to save money here. I forgot to mention I can install everything. Thanks in advance everyone for looking at this and recommending options/positions. The way I have it sketched out for the installation is to valve it and checkvalve it so I an either use all electric hot water, or use only oil indirect hot water, or temper incoming well water through electric hot water heater over to the indirect hot water tank.
 
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Old 02-25-14, 09:08 AM
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hello...

First off before suggestions are made, what boiler make and model do you have? ( For BTU reference)
What size megastore do you have?
What are the hi lo and differential settings in the aquastat, and what is the megastor t stat set at?

Is there a mixing valve?

Im not sure electric may be the answer here because you have an indirect.

Putting in a faster recovery indirect may be better suited and tweaking the temps some...

But I dont know until I review the data.

Oh additionally there are controls out there that will take the residual heat of the boiler and run the circ to the indirect. Meaning after a call for heat the hot boiler will not sit there. The circ to the indirect say will run for 10 minutes so the heat is not wasted...
 
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Old 02-25-14, 03:33 PM
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I know the hot water costs when heat is off. When heat is on, I do not. I have heard the argument that cooking a hot dog over a fire does not take away the heat from the fire and this is the same thing with winter indirect hot water. No one can tell me how much indirect hot water costs with a Peerless boiler during the winter. I can’t see exactly why it would be less than the summer but let’s say it is. Would I be using .5 gallon then a day for hot water? Who knows?
If you stick something cold into a fire, of course it takes heat away from it! How can it not? It's just that little weiner isn't taking much compared to what the fire is producing.

BTUs are what heats the water. It takes 1 BTU to heat 1 pound of water 1 degree F. Water is 8.33 pounds per gallon. To heat 1 gallon 1 degree it takes 8.33 BTU. To heat 40 gallons of water from 60 to 120 takes almost 20K BTU. It doesn't matter if it's summer or winter, if you use the same amount of water, and the temperature of the water stays the same, it will take the same amount of BTUs to heat it. BTUs don't care what the season is.

There will be probably less STANDBY losses during the winter due to the fact that space heating calls are pretty much keeping the boiler warm anyway... whereas during the summer the boiler might only fire every couple hours to reheat the water in the tank. The in-between periods the heat that remains in the boiler goes up the chimney as it cools and radiates into the home putting more load on your A/C system.
 
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Old 02-25-14, 04:09 PM
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The electric hot water heater label says the unit uses 4260 kwh but I am using 5000 as a baseline. 5000 x .18 = $900 estimate or $75 a month.
Check that label again - I'm pretty sure it says kW, not kWh. kWh depends upon the time the heater is on, which the heater's label would not know.
 
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Old 02-25-14, 04:56 PM
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The electric hot water heater label says the unit uses 4260 kwh but I am using 5000 as a baseline. 5000 x .18 = $900 estimate or $75 a month.
I missed that Gil, good catch... that ain't right ciphering!

It's a 4500 Watt element. It doesn't run 100% of the time. Turns on, turns off.

If it runs for one hour, that's 4.5 KWH

My electric WH costs about $40 a month to run. It's on a separate meter.

I know everyone says “more BTUs in oil than electric” but I am looking at costs.
Not everyone... you'll never hear me say that because it's comparing apples to persimmons.

You need to arrive at a COST PER BTU.

You can do that by knowing your electric cost per KWH ... AND the fact that ONE KWH = 3410 BTU

Also, the fact that OIL contains 140,000 BTU / GALLON.

And don't forget that it's probably only about 80% or so of that heat actually going into the home.

So, 80% of 140,000 is 112,000 ... so dividing this by 4.00 means that you are paying $0.000036 per BTU of oil heat.

I'm going to use 10 cents a KWH for the electric example, and electric is 100% efficient, you will put (nearly) all the BTUs you pay for into heating the water:

0.10 divided by 3410 = $0.00003

So, you can see that Oil at 4/gallon and electric at .10 / KWH are nearly the same cost per BTU, right?

Run some numbers of your own with what you actually pay .

I actually pay a little less for oil and a little more for electric so I think I'm sorta break even on that.
 
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Old 02-25-14, 05:00 PM
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Has electric hot water cost tipped against oil hot water cost so it is now cheaper?
No, not too likely in your area - maybe in the Northwest where there is hydropower?
 
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Old 02-25-14, 05:06 PM
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The way I have it sketched out for the installation is to valve it and checkvalve it so I an either use all electric hot water, or use only oil indirect hot water, or temper incoming well water through electric hot water heater over to the indirect hot water tank.
Do you disinfect (chlorinate or UV) your well water supply?

If not, I highly advise against creating domestic plumbing 'dead ends'. The water that sits in the unused portions of piping is a perfect place for things like Legionella, Giardia, E-Coli, etc to breed.

If you do create dead ends, provide a means of flushing the lines out ... maybe weekly or so.

Even on city water I would recommend " NO DEAD ENDS! "
 
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Old 02-27-14, 07:26 AM
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Everyone-thanks for replying and for the questions. For some reason, I thought I would get notices when there were replies but I must have missed asking for these. I just checked and saw everyone's posts. Sorry I took so long getting back. The boiler is a Peerless Model WBV-04-150-WPC and Aquastat is L8148A. Mega-stor is model MS-40. Boiler is rated at 178,000 and BTU is rated at 155,000. Aquastat is set at 180 degrees. I think it has 15 or 20 degree low setting meaning I link at 160 degrees boiler water, the boiler fires to heat the water in the boiler when thermostats are shut off. I've seen the high get to 190 degrees when it shuts off but mostly it seems to stay around 180 on gauge. The Mega-stor is set to 130 degrees (its own aquastat). There is no mixing valve.

I checked the electric hot water heater label and it definitely says 4622 kwh is rating.
 
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Old 02-27-14, 08:02 AM
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I checked the electric hot water heater label and it definitely says 4622 kwh is rating.
Are you possibly looking at the YEARLY ESTIMATED ENERGY USAGE? I believe that you are.

The heating elements used in electric residential water heaters are 4500 watts.

A heating element can't be rated in KWH, only in KW.

KWH is a time dependent number.

If you run a 4622 WATT ( aka 4.622 KiloWATT ) element for ONE HOUR you will have used 4.622 KWH.

In order to use 4622 KILOWATT HOURS, you would have to run that element for 1000 HOURS! That's 42 days without the heating element turning off at all... (or, if it's a yearly energy estimate, which I believe that it is, that 1000 hours of run time spread over 1 year makes sense)
 
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Old 02-27-14, 08:05 AM
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I've looked around for btu cost oil vs. elec and I see different things. At one site, it said the heat content of one gallon of oil =40.6 kwh in electricity. Oil @ $4.50 a gallon and (40.6 x.18 cents)elec=$7.31. This tells me oil indirect hot water in the summer is still cheaper than elec. In the winter, who really knows how much indirect hot water costs (same as summer months or less?).

Yet...the label kwh usage 4622 x .18 cents kwh=$832 or $69 monthly and I know at least in the four months I have no heat on, I use a gallon a day or $135 monthly. I know these numbers are not set in stone but for the sake of this conversation, these are what I am using. If there are more BTUs in oil and less in electric and it costs more to heat water with electric as per the first paragraph, I can't get the monthly cost different in the second paragraph. It seems to cost more to use electric to heat hot water following the BTUs but following the label, it seems to cost less.

I don't know what to believe.
 
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Old 02-27-14, 08:09 AM
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Yes, I am looking at yearly estimated energy usage. Should I look at it differently?
 
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Old 02-27-14, 08:28 AM
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the heat content of one gallon of oil =40.6 kwh in electricity
That's fairly close... given that the heat output of a gallon of oil can actually vary somewhat. The 140,000 BTU figure that I used is a close estimate. ACTUAL heat output may be somewhat lower, perhaps 139,000 BTU.

SO, if you take 139,000 BTU and divide by the 3410 (actually 3413 I believe) you come up with 40.76 KW ... and NOT KILOWATT HOURS ... it would only be kilowatt HOURS if you burned that one gallon of oil in ONE HOUR. If it took TWO HOURS to burn that gallon of oil, you would be using the energy at the rate of 20.38 KW HOURS.

And you still need to know the EFFICIENCY of the oil burning appliance... HOW MANY of those BTUs that are being produced are actually being USED AS HEAT and how many go up the chimney.

As mentioned, virtually all the electricity you pay for is being used... 100% efficient... (the small exception is any heat lost to the resistance of the wiring, which is quite minimal and doesn't make sense to even consider it)

So, that 40.6 KiloWatts of oil heat energy is really more like 32.5 KiloWatts with the efficiency factored in at 80% (which is a 'ballpark' number that should be close enough to give reasonably accurate estimates).

Your cost of oil at $4.50 a gallon seems HIGH... last price paid here a couple weeks ago was $3.60 and electricity cost here is about 12 cents a kilowatt hour.

My figuring is that electricity is only SLIGHTLY more expensive than OIL at this time, for the prices that I pay. Oil will definitely be more expensive as time goes on... so will electricity, but probably not at the same slope of increase.

As I mentioned earlier, it costs me about $40 a month to run my 40 gallon electric water heater.

Even at $4.00 a gallon for oil, that's only TEN gallons a month...

A gallon a day seems pretty extreme to heat water, you might think about getting that tank checked for leaks!
 
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Old 02-27-14, 08:30 AM
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Yes, I am looking at yearly estimated energy usage. Should I look at it differently?
No, that's fine... as long as you understand that it is an ESTIMATE ONLY and that your mileage may vary. I actually use LESS electrictiy on mine than the yellow label on the heater says...

And also be careful about mixing the terms KiloWatts and KiloWattHours, because they most definitely are not the same thing!
 
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Old 02-27-14, 08:38 AM
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Dont forget troop he is running a 160 low setting... Also if he is over radiated he may not need a 180 hi...

Also he may be better suited as a cold start???

Im sure he can tweak and get the oil consumption down... As well as nozzle choice for that huge boiler...
 

Last edited by lawrosa; 02-27-14 at 11:06 AM.
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Old 02-27-14, 08:44 AM
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Thanks for the info. Here in NY in the mid-Hudson valley, I can call around and get $4 a gallon. Full service companies are $4.40. Electric from Orange and Rockland is about 10 cents delivery and from my supplier 8 cents for electric supply. In South Jersey where I have a rental property, I just paid $4.10 a gallon for oil there. Where are you getting oil for $3.60? I will come fill up! I had my indirect Mega-stor set for years at 140 degrees so that when it went 40 feet or more to the other side of the house, I could run my dishwasher and washer without having to let the water run in the sink for a few minutes. I also like to be sure nothing is afoul in the tank and 140 degrees seemed to be a good setting. I only just lowered it to 130 degrees when I put in the new aquastat control a few weeks ago. Our washer runs at least two loads every other day, our dishwasher runs daily, and we have two adults showering and two kids showering so it seems we use close to a gallon a day.

You mentioned electric at 10 cents. Are you excluding delivery costs?

It is starting to look like elec hot water may be viable for me at least during the summer months. What about shutting down the Peerless completely-recommended or not? I am concerned about leaks from contracting parts, etc. Thanks again for your time and comments.
 
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Old 02-27-14, 08:53 AM
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The nozzle on the Peerless is 1.25 80 degrees B. I get the unit serviced annually and the probes, tests etc. they do afterward with stack temp etc. always returns about 85-85% efficiency. In the late March time, I used to dial down the aquastat temp to min of 150, lowest setting until about late November to try to save. I put a new aquastat on a few weeks ago and in another thread it was determined it was cold start. I tested this by shutting off all thermostats and lowering hot water from 140 degrees down to 130 degrees. Yes, the water temp dropped to about 150 degrees before it fired. Troop figured this out. Since I have indirect hot water now, I had the temp up to 140 degrees and that kept the boiler water hot all the time with the aquastat set to 150 degrees. In other words as a lay person, if I didn't have indirect hot water I would say if my aquastat was at 150 degrees and my water went down to 130 degrees in the boiler until it fired (and this was Sept-Nov or so) then yes, I would see savings. I can't see how a cold start boiler helps save money when there is an indirect hot water tank attached but I guess that is for another thread.

Do you have a recommendation for a smaller nozzle? The house is finished basement, and two stories = 3200 square feet. Colonial style-built in 2001. 650 gallons of oil a year isn't that much for heat and hot water thanks to the wood stove but I am thinking about oil going through the roof next year and it pisses me off to leave the boiler on in the summer to heat its water plus the indirect...knowing standby heat is being lost plus what is going up the chimney. So this is why I am exploring elect hot water
 
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Old 02-27-14, 11:03 AM
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You mentioned electric at 10 cents. Are you excluding delivery costs?
Just an example to make 'head math' easier. I think that 'all in' I'm looking at about 13 cents / KWH.

Where are you getting oil for $3.60?
I don't use the 'Mega Suppliers'... I buy from independents.
 
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Old 03-02-14, 09:38 AM
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For the cold start understanding help. Cold start on boiler means NO lower limit (only one dial (unless digital) in aquatstat on boiler- if there is no call for heat from a thermostat (either water heater or house) the boiler will not turn on even if it gets down to room temperature or colder.

Warm Start has lower limit- (2-3 dials (or digital) in aquastat on boiler)- Boiler doesn't care if there is no call for heat from thermostat. When temperature reaches low point(plus differential) it will turn on to reheat. Doesn't care if your in another country not using hot water and you disconnected thermostat of house. it will still go 160-180 or whatever you set at.

I have a Superstor now, old house had Boilermate. Standby temperature loss was 1/2 degree per hour, t-stat had 10 degree differential. basically boiler would fired once every 20+ hours IF i didn't use the hot water. The more showers/water used the more it fired to reheat (just like an electric will). 200 gallons would go 6-7 months maybe more during April-November at old house, still working on this one.

I also have a WBV-04 with Riello head and it is a 1.0 x 80. Previous owner had a .75 I might go back at some point. I just added the Superstor, removed tankless coil and made it cold start. You can help your standby loss by possibly insulating water heater better. Both houses I also added a Field Oil Vent Damper Patriot Supply - 46561706 which reduces the standby heat loss of the boiler when not running.

Many threads here at Doityourself with both sides but for some (myself included) some of the heatmanagers (Beckett, Intellicon, I think Hydrostat) might also reduce usage. 650 per year on that size house where you are and water demands is not bad IMO. I can only go by old house as not enough info here yet. Old house went from crappy warm start boiler with tankless coil to weil mclain with boilermate. Old was 1400 gal/year, new was 1000 gal/year, added Intellicon dropped to 700 gal/year, added Oil vent damper dropped to 650 gal/year. Didn't get to all the air sealing and better insulation everywhere but did some.

I'm on Long Island, last delivery was on 2-16-14 for $3.799 for 200 gallons. I use smaller independent COD. They and ALL the mega places get it from same supply depot 2 towns over.

Electric water heater MIGHT be option in future. Many around are getting solar which might make that more attractive PSEG is outrageous now I can't think to add more electric demand.
 
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Old 03-03-14, 03:22 PM
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Sequoiasoon, thanks for the reply. I saw the video on the field oil damper. It looks interesting. I have looked at the Intellicon unit and I think I am going to look again. Was it easy to install? Regarding the Field Oil Vent Damper...does that replace an in flue damper? I have a weight-balanced one. Does that get taken out? The Field Oil vent damper wiring is easy enough?
 
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Old 03-03-14, 04:04 PM
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Regarding the Field Oil Vent Damper...does that replace an in flue damper? I have a weight-balanced one.
I think you mean the 'Barometric Damper' ? If so, no, that stays.

The Field Oil vent damper wiring is easy enough?
Not overly complicated.
 
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Old 03-03-14, 10:11 PM
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Like NJ Trooper said,
Your weighted Barometric damper would stay. The Field OVD installs on your flue pipe somewhere between the Baro damper and where the pipe enters your chimney. You need to cut/remove about a 12" piece of your existing flue pipe. Wiring is pretty easy if you have done any and can follow a wiring diagram. The part that is nice to see and you know has to help, is on a windy day (when your boiler is off) you see the baro damper swinging wide open as the draft pulls heat out of your home and boiler. The OVD closes 3 minutes after the last burn cycle, when this closes you see the baro damper close and stop swinging and you know all that heat is now staying in. It does have a high temp safety sensor that installs on boiler side so if heat rises to fast or certain temp it will kill power to the burner presuming that something is blocked/defective.

Intellicon is also pretty simple to wire up again following wiring diagram. A little more to read as it has wires for line voltage and 24V for gas valves etc. Definitely not hard to install and if your boiler is oversized like many out there could save a bunch. Mine showed avg 30% savings and oil usage showed roughly that. Close enough that it paid for itself within 2 months of use in my case.
 
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Old 03-30-14, 07:10 PM
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Life's a funny thing

The top part of the hot water nipple on the indirect started leaking; it turned out to be rotted away. So, I did have to cut in the electric hot water heater. Now I have at my leisure the project of getting the rusted nipple out of the indirect. Meanwhile, when it rains it pours. The circulator pump died yesterday and it was that and a transformer to get the boiler back on. I will see what the first month's electric bill is for the elec hot water heater. I do want to get the nipple out of the indirect and get it back in working order. When power goes out, the generator runs enough for the wife and kids to be happy...heat, lights, fridge, etc. The bad thing is without the indirect, there will be no hot water during an outage. So, I am getting my hack saw blade to slowly cut inside and try to get the pieces of the nipple out of the threads. For this job, I'd pay real money. Anyone want to come over for a case of beer and some money to get the nipple out?
 
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Old 03-31-14, 03:15 PM
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My guess is that electric would probably be cheaper for the non-heating season and here is why. Assuming 139K btu/gallon and 3.42K btu/kwh let's assume a down the line price of $4 for oil and 25˘ for electricity.

A buck will buy you either 35K BTUs of oil energy or 14K BTUs of electricity in raw form. Assuming 80% burn efficiency* that 35K drops to 28K. So you are getting roughly twice the "energy" buying oil than electricity.

What messes up the equation is what you are actually having to "energize".

With the electric water heater, you're heating 330 pounds of water plus the insulated tank's mass which would most likely be most of its 100 pound weight. Let's assume 70 pounds so total load is 400 pounds.

With oil you have that same 400 pound load plus a good chunk of a 600 pound boiler, plus another 125 pounds of boiler water, plus whatever weight of water and piping connecting the boiler to the indirect. In addition, this mass works against you to some degree if you air condition much over the summer.

I think both tanks makes sense. In the winter, all that extra load is actually negligible of course because its heating the house - but in the summer time it just kills the power to weight ratio if you care to look at it in those terms.

Note: Not even sure if a boiler gets 80% efficiency if it tests at 85%. It depends on how long it takes to get the boiler up to that 85% and averaging that over each heating cycle.
 
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Old 03-31-14, 03:48 PM
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25˘ for electricity.
Good grief! Is electricity THAT expensive in Cali?

I think 'all in', including delivery and service charges I'm around 12˘ a Kwh here in Joisey.

Yes, it's going to go up, everything does, but oil will escalate faster than electricity.

Given these numbers, at this point with the price of each, here at MY location, it's pretty much a break even between the two, with electricity becoming more economical as oil rises faster than electric.
 
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Old 03-31-14, 06:23 PM
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Those are future "down the line prices" and I made electricity worse on purpose to show that even at twice the price net per BTU it still might be more expensive if you're heating roughly 3x the mass to end up with the same 40 gallons of hot water.

I think the price here is in the 15-18˘/kwh range.
 
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Old 04-01-14, 12:26 AM
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I haven't searched yet but maybe somebody has.

Do any of the manufacturers make a hybrid or dual stage type indirect water heater even if larger size? Something like Electric elements to maintain and heat the water from 120-140F but if it drops less than 120 the boiler kicks in and gives more rapid recovery.

Thinking the just one person showering scenario and maybe electric keeps up but 2 showers at the same time (as I often have in my house) and more BTU's needed.

Many of my neighbors are doing the Solar Panel lease deals which might make the electric water heater a more enticing option also if I go that route.
 
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Old 05-16-14, 05:25 PM
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Here is an update. The indirect hot water nipple started leaking due to corrosion and it was replaced under lifetime warranty. I have had it out of use since beginning of March. It looks like the 80 3 inch foam electric hot water heater I cut in is costing about $50 a month @ 16.5 cents a kwh and with a family of four. This looks like it is about half the cost of oil @ 30 gallons of oil a month times $3.50 a gallon of oil now that things have calmed down in the oil market a bit. Oil is about $105 a month for hot water based on my usage.

So...what I have learned is no one on the planet knows how much indirect oil hot water costs in Dec-March. From April to Nov, yes ... because my heat is not on (woodstove where necessary) and I get a fill up in April until late Nov. In the summer, how much oil it takes to heat hot water vs. the rest of the heat going up the chimney (standby loss) is not known. A gallon of oil a day has heated water and standby loss attached. It is still a gallon a day in my case but what parts of a gallon go to heating water and to standby loss...well, that is anyone's guess.

In the winter, the boiler is running and maybe more heat from the boiler is circulating around the house and maybe there is no standby loss. There is heat up the chimney but some folks have discussed adding a Tekmar boiler control and a draft control to handle that 365 days a year.

So, while a gallon a day in summer is what is spent on hot water + standby, no one seems to know on the planet what hot water actually costs in the winter. If there is less standby loss, is it less than a gallon of oil to heat hot water per day? All I know is if I use 600 gallons a year previously, I may use 450 gallons a year if I go with electric hot water for six months. If I want to dream and guess *maybe* a winter savings of .25 gallons a day or .75 gallons a day across six months because of less standby then maybe I am saving 45 gallons of oil over the six other months (Sep-March) for a rounded off total of 200 gallons. 150 gal + 45= about 200 gallons in savings. That brings me down to 400 gallons a year and yes, I recognize I am paying more in electric for electric hot water but it is still less than what oil indirect hot water costs.

So, if I use 350-400 gallons of oil a year @ $3.50 along with the woodstove most days in the winter...that is doable. I am planning on using elec hot water for this upcoming winter just to see the oil consumption from Jan-March. For heat and hot water for 3500 square feet and 2.5 bathrooms and washer, dishwasher, I was doing 80 gallons a month this past winter. Without oil indirect hot water, maybe it will be 60 gallons or less per month in those months. Maybe it will be less. With an electric hot water tank that is cool to the touch everywhere and with R-24 insulation and at .16 a kwh, $600 a year in hot water sounds better than $528 for six month with oil and who knows how much for oil hot water in the other six months (same, less?).

I will put back in the replacement indirect hot water because if the power is off for days at a time, the generator does a great job for well water, lights, heat, etc. but not for hot water unless the indirect is online. I still have to figure out how I can keep it "ready" but not let water sit in it and go stagnant. Any ideas or comments on this would be appreciated (oil hot water cost in Jan-Mar, standby loss, etc.).
 
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Old 05-16-14, 06:08 PM
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Pipe the water so it goes through the indirect first and then into the electric. Basically using the indirect as a cold water storage. Use a switch on the thermostat leads to indirect. No power to tstat on indirect, no call for heat but water will flow through it. If/when you need it, turn switch on for indirect and boiler will kick in. Flip breaker off for indirect so no power demand there.

Pipe in some ball valve/bypass at the same time so the hot from indirect does NOT go into the electric but right to hot water supply. Otherwise you'll have all the hot going into the electric with no heat to maintain it. If that happens and you need hot you'll need to fully empty the electric before you get hot water out to faucets.

Side notes:
Oil currently by me is $3.259/gal for 200 gallons. Looking at the Aquasmart history with the warm days I have had multiple times of 700+ minutes of "off" time when no hot water demand. That is mixed in with many of the shorter cycles as it reheats water.

I have noticed on a couple occasions that my hot water is not as hot as I'd like. This has happened at end of warm day with nobody home most of day. One kid showers for pretty long and I didn't hear boiler fire. Right after I jump in shower and other kid jumps in othershower so now 2 at the same time demand. Aquasmart still wants to keep temps low instead of firing to limit so Indirect does not get the full BTU input recovery. I still need to look at that some more. Maybe somehow trigger the DHW lead on aquasmart at the same time?
 
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Old 06-10-14, 06:11 PM
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Electric Hot Water and indirect oil wrap up

It looks like approximately $55 a month for electric hot water (very hot, too) for 80 gallon tank with three inches (R-24) foam around it. Tank is cool to the touch. Replacement indirect tank coming soon (under warranty, horray!). After doing lots and lots and lots of Googleing, the best I can come up with regarding oil heating costs at my locked in $3.52/gal price (also horray!) is for five months (May-Sept) hot water with indirect oil tank = 150 gallons. Oct-April (estimated) = 95 gallons. So for the year, I figure 245-250 gallons of oil for indirect hot water. My best guess: oil @ $3.52/gal costs me $105.60 a month) and electric hot water is about $55 a month. During Oct-April, maybe oil indirect hot water is 95 gallons or about 14 gallons of oil a month or $48.24. So while there is a savings of about $50 a month during May-Sept, in other months maybe there is a cost of $7 extra a month to use electric. I won't sweat that.

Why do I want the indirect hot water back in? Power outage and my generator won't handle the electric hot water tank. What will I do in the winter with two tanks. Don't know yet. What am I happy about? Even though I am paying about $660 for hot water via electric for the year, I am blowing off a tank of oil. Last year, prices were ugly. I am locked in for this year but imagine all these oil price and usage calculations with oil @ $4.35 or so. NY has lots of taxes on everything including home heating oil that must be sulfur free. Bottom line: very happy with (free) electric hot water heater someone gave me. Even happier to be using maybe 400 gallons only for the year to heat my basement and two floors along with my woodstove.
 
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Old 06-15-14, 03:02 AM
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Might not be fun to pipe (but with a enough valves all is possible), if you could use the electric as a tempering tank in the winter and the indirect as a tempering tank in the summer, there will be some marginal yet real gains in efficiency... and neither tank sits idle.
 
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Old 06-15-14, 06:07 AM
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Here's a question. Would money be better spent on increasing fuel savings on what you have. For instance outdoor reset. Now you can save money all winter to help offset the summer cost. A timer on the water Hester. I put one on my oil fired water heater, only oil appliance in the home. I used to get 100 gallons once a year. Just me and my wife. Put a timer on and the heater is on 2 hours in the AM, 4 hours in the evening. Saturday only day it is different is from 8AM to 2PM and again from 6-10 PM. I now get 100 gallons every 17 to 19 months. I usually order when tank is down to 20 a 25 gallons (measured on stick and looking at a tank chart).

I also added a timer to a friends IWH and he claims savings but I have no real info.

Also many jobs I am suggesting not using DHW priority unless needed for large waster demands. Only one so far had to turn it back on. When a heating system is zoned you never need all boiler btu's when all zones are not calling and boiler is probably oversized. The boiler operates more efficiency when more load is on it. Higher heat transfer when water temperature is lower and burner run time is longer. Shorter cycles reduces boiler efficiency.
 
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Old 06-15-14, 08:18 AM
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Looks like the cost of oil will go through the roof this coming winter and therefor your suggestions to increase efficiency should have a short pay back , more comfort , and a quieter system
 
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Old 06-17-14, 06:52 PM
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Outdoor reset

I was thinking of an Intellidyne because the refurbished aquastat only goes as low as 180. However, when I read the prior posts it looked like this topic was a spirited discussion and I decided not to ask. I am still looking into this. As for the timer, RBeck that is a thought. I don't know what the voltage would be for the aquastat wire on the indirect. I will have to check that. Thanks for the idea.
 
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