New member/DHW questions

[johnnh]

Hello All,
I have frequented this website for the last 4 months and have ingested tons of information. Yes. it took me this long to sign up, but your fingerprints are already in my house. I have succeeded in replacing my oil fired 26 year old Weil Mclain boiler with an Enviro M55 steel two months ago. The boiler is still there and very healthy, but it will be used only when the pellet stove for one reason or another is not functional (hopefully never). Holy God, what a machine. The oil boiler heat hasn't kicked on once since I bought it. But, now I have a question on DHW choices.

Some background:

House built 1988, I bought it in 1992. 2220 sq. ft. cape cod style.
Original setup was 100KBTU Weil Mclain boiler with internal on demand coil in an unfinished basement.
In 1996, got sick of the on demand coil due to garbage performance, and replaced it with a separate 32 gallon oil fired John Wood JWF307 tank. The boiler was set up to preheat the water going into the DHW tank. Oil was cheap then.
Two children, ages 17 and 14, along with my wife. The laundry goes non stop. The dishwasher goes non stop.

My John Wood is now 18 years old, still going, but is sucking too much oil and is a ticking time bomb. It has been an unbelievable performer. Never have I been without hot water. The recovery time must be good on this thing due to the jet engine underneath.

I would like to replace it now before trouble starts. It has treated me well, and I have got my money's worth.

Thoughts/Concerns: No more oil, although I realize that none of us can predict future prices on anything. I do not have the option on natural gas. Propane, as far as I'm concerned, is oil. I do not want any on demand DHW set up. I will not spend up front costs that will take decades to pay back, along, with what I believe, is suspect performance.

My thoughts are to just go electric with a larger tank (66 or 80) and call it a life. Electricity is $.1678 here. I have looked at the hybrids, but I am worried that the 50 gallon GEO just will not be enough, especially with recovery time. Hybrids also scare me with the potential breakdown concern that I have read about . After reading about them, I don't trust them. Maybe you guys can convince me. Overall, I want hot water, and plenty of it without thinking about it. . I will value anything you have to say. Thank you,

John

 

[maple1]

Go with your thoughts.

 

[rkusek]

80 gal electric tough to beat. I have used all the water before though. 4 showers while laundry has been running and the dishwasher but 99% of time not a problem.

 

[mustash29]

I'd look into a hybrid "solar" storage tank.

You can get something like an 80 gal tank, with an upper electric "backup" element, and one or 2 heat coils (solar, oil boiler, wood boiler, etc) and then hook up a Nyletherm (220 volt) or Geyser (120 Volt) heat pump.

You get 80 gal of storage, low cost heat pump hot water most of the time, electric back up when needed, can run the oil for backup as well. The coil would function just like any other indirect fired tank. Heat pump set to 130, electric set to 120, oil set to 110.

 

[johnnh]

Go with your thoughts.

Hi Maple1,
I'm glad you posted because I wanted to ask you something. Some time ago you posted this:

Our 2 year old 80 gallon electric hot water heater uses about 6kwh/day on average. Family of 5.

If my math is right, that comes to ~2160kw/hr per year. I don't doubt you, but that is far less than the sticker of "average" use of ~4773 kw/hr per year. This isn't a vacation home, is it? Are Energy guide stickers usually that far off? I would be so happy if that were my bill.

Thanks,
John

 

[maple1]

No, that's a house. Family of 5.

I'm not sure how long ago I posted that estimate, but when I took a second look at my most recent power bill a couple weeks ago, and looked back at the past years use, it said the two months that we used just the electric tank (July & august) averaged only 4 kWh/day more than the other 10 months a year. So I feel quite safe in saying it uses between 4 & 6 kWh/day.

I've been very surprised by all that. I'd always had the impression that electric was more expensive - until I got off the oil & saw for myself.

 

[BoilerMan]

Remember that the electric is directly related to what you use. Maple's family of 5 may use less hot water that someone else's family of 2............

John, welcome aboard!

It's going to be tough...near impossible to bat what you have currently for an oil setup. Thats why everyone went with oil DHW, .85gph (average fireing rate) is a LOT of heat almost 94,000 btu/hour @ 80% efficient. There is no recovery like that in electric, so you need the storage to make upthe difference.

I think Mustash29 hit it right on how I'd do it! I actually have a "solar" tank with the two coils in it. Lower is on wood, upper on oil, and HPWH t'd into drain and returning in a tapping half way up the tank. 115gallons is plenty for anyone.

TS

 

[johnnh]

No, that's a house. Family of 5.

I'm not sure how long ago I posted that estimate, but when I took a second look at my most recent power bill a couple weeks ago, and looked back at the past years use, it said the two months that we used just the electric tank (July & august) averaged only 4 kWh/day more than the other 10 months a year. So I feel quite safe in saying it uses between 4 & 6 kWh/day.

I've been very surprised by all that. I'd always had the impression that electric was more expensive - until I got off the oil & saw for myself.

If I go electric, I'm hoping it errs on the positive side like you. According to Energy Guide sticker, 4773 kw/hr/yr X .1678 = $801. That's approx. what I spend now with the oil. I'm not going to argue over +/- 200.00. It's not going to break me. I just don't like to be taken, whether it be Middle eastern oil or Public Service of New Hampshire. Decisions......

 

[maple1]

Do you know how much oil you use for DHW now with the JW?

Also, you said above 'no more oil'. What kind of shape is your oil tank in? You also mentioned not wanting to use propane - but do you have propane now that you use for other things?

After weighing everything at my place, I decided to get rid of all my oil stuff all together. Factors for me were next to no need for backup oil heat (as long as I'm able to feed wood to a fire), an oil tank that was almost due to be replaced (mandatory per insurance - seemed like a racket to me but that's another issue), freeing up of space & chimney by getting rid of the oil boiler & oil tank, and elimination of any potential oil 'accident' risk and liability. We now have an electric hot water heater for when I don't want to burn wood for DHW, and electric boiler for backup heat (relatively cheap & easy install, takes up next to no space, and doesn't need a chimney).

I guess my point is, evaluate everything.

Also, BoilerMan has a good point about how much hot water would actually be used. We have 3 kids, 14, 17 & 19. The oldest started college this year but is now back for the summer. Only one of us doesn't shower every day (the youngest, must be an age & boy thing). Our dish & clothes washers don't go non-stop, but the dishwasher runs every couple of days, the clothes washer (18 year old top load likely not that efficient) maybe a half dozen loads a week (usually all on the weekend). Maybe not super heavy use, but I don't think I'd consider it abnormally low. I did turn the temp down on the heater from it's factory setting of around 140 to somewhere around 125.

 

[johnnh]

Do you know how much oil you use for DHW now with the JW?

Also, you said above 'no more oil'. What kind of shape is your oil tank in? You also mentioned not wanting to use propane - but do you have propane now that you use for other things?

After weighing everything at my place, I decided to get rid of all my oil stuff all together. Factors for me were next to no need for backup oil heat (as long as I'm able to feed wood to a fire), an oil tank that was almost due to be replaced (mandatory per insurance - seemed like a racket to me but that's another issue), freeing up of space & chimney by getting rid of the oil boiler & oil tank, and elimination of any potential oil 'accident' risk and liability. We now have an electric hot water heater for when I don't want to burn wood for DHW, and electric boiler for backup heat (relatively cheap & easy install, takes up next to no space, and doesn't need a chimney).

I guess my point is, evaluate everything.

Also, BoilerMan has a good point about how much hot water would actually be used. We have 3 kids, 14, 17 & 19. The oldest started college this year but is now back for the summer. Only one of us doesn't shower every day (the youngest, must be an age & boy thing). Our dish & clothes washers don't go non-stop, but the dishwasher runs every couple of days, the clothes washer (18 year old top load likely not that efficient) maybe a half dozen loads a week (usually all on the weekend). Maybe not super heavy use, but I don't think I'd consider it abnormally low. I did turn the temp down on the heater from it's factory setting of around 140 to somewhere around 125.

My boiler has not run for heating purposes for exactly two months since I put the pellet stove in. In that time, by extrapolation of the oil gauge on the tank, it looks like I have burned ~35-40 gallons. Thats' all I have to go by. I have propane for my cooktop, but that only gets filled once in a blue moon. Once a year maybe. The latest bill came yesterday by coincidence. $5.40. Holy God.

Yes, I said no more oil only because I feel that it's time to break from it. It makes me feel good that my money isn't flowing over to the Middle East. Judging by how much oil I am burning minus heat purposes, I may come out ahead even though electricity is high here. We can't predict future prices of commodities, so who knows, oil may drop big time soon. I lived through the 70's, but by 1983 oil prices eased and went on a great price run.

I laughed about the showers and the 14 year old. Same here. They're all the same.