Suggestions for Hot Water?

[jcleary47]

So having put in a pellet stove in my house, I have just about near ended my need to use the furnace and subsequently oil for heating my house other than a single bedroom above the garage.

My hot water is also heated by the furnace via oil burner, and now that I am not using oil to heat my house, it pains me to see the oil guage go down from using hot water so I'm considering other options.

I have developed a moderate interest in the GE GeoSpring Hybrid water heater, but wasn't sure if the cost of running that would be lower than the cost of using oil to heat my hot water. I guess it would certainly be more efficient in the summer, but less so in the winter (I live in Maine).

I don't know if it's an accurate assumption or not, but I would think in the future the cost of oil is more likely to increase than the cost of electricity, so limiting my oil requirement in my home further seems like a no brainer.

Anyone have any experience with hot water heaters like this?

 

[velvetfoot]

No, but I figured a regular electric water heater would be cheaper than oil.

 

[Chain]

Funny you ask this question as I'm in exactly the same boat. Well, almost. I pre-heat my water with my oil burner before it's moved to my electric hot water heater. I'm at the point where I should replace the well over 10 year old electric hot water heater and thus am considering my options. I think I should just buy a new hot water heater and leave it completely removed from the oil burner as I too believe electricity will remain cheaper than fuel oil for the foreseeable future.

All this has made me wonder about the possibility of utilizing liqufied natural gas as my back up heat source and method for heating hot water. One of my local energy companies has recently begun advertising this new heat source but I have yet to check into the cost of installing it, converting the boiler, etc....Does anyone have any experience with this new form of Natural Gas?

 

[jcleary47]

Not much experience with natural gas here as it isn't available in my neighborhood.

I'm terrible with math but I've been trying to figure some things out with this electric hybrid heater.

So it says on average it uses 1830 kWh / year which works out to around 152.5 kWh / month (less in summer, more in winter because it can use warm air to heat the water which will work better in the summer months).

Right now I get charged $9.41 for the first 100 kWh's and then .065831 for each additional kWh.

I'm guessing on average it would cost me about $13-$15 / month to run this hybrid water heater.

Now I believe that 1 gallon of #2 Oil is equal to 40.5 kWh, which means the equivelent is 45 gallons of oil to equal the 1830 kWh the hybrid heater would use.

45 * 3.50/gallon is $157.50 / year in oil and the $13-$15/month if correct is about $180/year so is the oil actually cheaper? I don't know the efficiency rating for a furnace using oil to heat water but maybe 1 gallon generating 40.5 kWh is a stretch.

Then again I might be doing all of this wrong because I am horrible at calculating things.

 

[velvetfoot]

All this has made me wonder about the possibility of utilizing liqufied natural gas as my back up heat source and method for heating hot water. One of my local energy companies has recently begun advertising this new heat source but I have yet to check into the cost of installing it, converting the boiler, etc....Does anyone have any experience with this new form of Natural Gas?

I hadn't heard of that. Do you have any specifics?

 

[Jags]

No, but I figured a regular electric water heater would be cheaper than oil.

I think VF hit the easy and cheapest (short term) solution.

 

[Seasoned Oak]

No, but I figured a regular electric water heater would be cheaper than oil.

Exactly,in fact if you dont turn it up too high, say just hot enough to use all hot when taking a shower ,your power bill will hardly budge. We have a 30 gallon electric hot water heater supplying 7 people and never run out of hot water. Kick the oil habit completely.

 

[maple1]

Not much experience with natural gas here as it isn't available in my neighborhood.

I'm terrible with math but I've been trying to figure some things out with this electric hybrid heater.

So it says on average it uses 1830 kWh / year which works out to around 152.5 kWh / month (less in summer, more in winter because it can use warm air to heat the water which will work better in the summer months).

Right now I get charged $9.41 for the first 100 kWh's and then .065831 for each additional kWh.

I'm guessing on average it would cost me about $13-$15 / month to run this hybrid water heater.

Now I believe that 1 gallon of #2 Oil is equal to 40.5 kWh, which means the equivelent is 45 gallons of oil to equal the 1830 kWh the hybrid heater would use.

45 * 3.50/gallon is $157.50 / year in oil and the $13-$15/month if correct is about $180/year so is the oil actually cheaper? I don't know the efficiency rating for a furnace using oil to heat water but maybe 1 gallon generating 40.5 kWh is a stretch.

Then again I might be doing all of this wrong because I am horrible at calculating things.

Standby losses & efficiency differences make comparisons based just on unit fuel energies & costs pretty well useless.

I would go electric - either heat pump or resistance - and get rid of the oil all together. If you still might need something for backup heat, either some portable electric ones or some baseboard rads.

 

[JDenyer236]

We installed the geospring for just this reason. In heat pump only mode it runs us about $20/month for a family of
three. In straight electric mode it runs us $50-$60 month. Oil was costing me $116/month in the summer with no space heating. Our electric rate is 14 cents/kwh. Before buying one of these you need to understand the installation requirements, and their limitations. You will need an area that is at least 700sqft of unobstructed space, ie an area 10X10X7. This area does not need to be a separate room, so for example you can put it in your basement or garage. The geospring will use the heat pump until the ambient air is 45F, after that it uses the electric elements, so if this is going into an unheated garage then you will likely be using it as a straight electric heater in the winter, which is fine but your savings will be less, although I still save about $56/month even on straight electric. Fan noise is something to be considered, they are not loud but the fans do make some noise, they are about as loud as a dehumidifier. We really like ours and have not run out of hot water yet, and wifey likes her long hot showers. Jcleary, don't forget to substract standby and stack loses of having a boiler being hot all day just incase someone needs hot water. These losses could be as high as 50% depending on how often and how much you use the hot water. The less hot water you use the more $$$ goes up the chimney. Think of it as gas mileage, if you are driving at 50mph and get 30mpg you are pretty efficient because you are using that energy to do useful work. If you idle in the driveway all day long you get 0mpg because you are wasting all that energy because you are doing nothing useful with it. With oil fired boilers and tankless coil water heating, the less hot water and heat you use the more inefficient it becomes. If you have your boiler on while you are away on vacation for a month then your standby and stack losses are 100% for that month, if you burned ten gallons during that month then you literally sent $35ish dollars up the chimney.

 

[jcleary47]

Excellent information. From what I can see, I don't have any sort of storage for the hot water, so I'm assuming my furnace heats it on demand?

Not sure what that does in terms of efficiency but from what you said, it sounds like the oil burner isn't that great efficiency wise.

There's only 2 of us in the house, and we don't take particularly long showers or anything. Maybe 15 minutes on weekday mornings, 20-25 on the weekends. I do have a dishwasher, but that only gets run at night once a week.

My basement is very wide open and quite large and it seems to stay pretty warm even in the winter so maybe this hybrid thing would be a good option.

I just feel like I'm using way too much oil just on heating hot water alone and its getting old.

I mean, I filled up my oil tank for about $700 on 10/03 and at the end of November I've used about 1/4 of a tank on basically just heating the water I've used alone. That doesn't seem right to me.

 

[velvetfoot]

Warm in the winter? I wonder why? Could it be the oil boiler?

 

[jcleary47]

Probably

 

[Ehouse]

Exactly,in fact if you dont turn it up too high, say just hot enough to use all hot when taking a shower ,your power bill will hardly budge. We have a 30 gallon electric hot water heater supplying 7 people and never run out of hot water. Kick the oil habit completely.

I was just thinking about this today. If I turn the boilermate ( propane ) way down, (even lower than you're suggesting) and put a small electric on demand at each shower, what would the savings be? Sort of a storage/preheat on demand hybrid. Keep the propane for outages rather than going all electric. Don't really need piping hot except for showers.

Ehouse

ng hot water alone and its getting old.

 

[woodgeek]

To the OP....on paper ~50 gallons of fuel oil has enough energy to heat a years worth of DHW. But typical standby oil usage is 200-300 gallons/year. IOW, you can burn 4-5 gallons of oil on standby for every one that heats the shower. Hard to believe, but that is the tech from the days when oil was <$1/gallon.

Any electric tank that is reasonable eff (get a tank with 2" of foam) will save you a bundle on oil (e.g $500/yr). The HPWH will save you maybe $200/yr more than the resistance, so it will be cheaper after 5-6 years. IF you go that route....look for rebates. I got $300 for my 80 gallon Voltex, which I like a lot.

 

[sesmith]

Right now I get charged $9.41 for the first 100 kWh's and then .065831 for each additional kWh.

I'm guessing on average it would cost me about $13-$15 / month to run this hybrid water heater.

Now I believe that 1 gallon of #2 Oil is equal to 40.5 kWh, which means the equivelent is 45 gallons of oil to equal the 1830 kWh the hybrid heater would use.

45 * 3.50/gallon is $157.50 / year in oil and the $13-$15/month if correct is about $180/year so is the oil actually cheaper? I don't know the efficiency rating for a furnace using oil to heat water but maybe 1 gallon generating 40.5 kWh is a stretch.

Then again I might be doing all of this wrong because I am horrible at calculating things.

Based on the electric rates you stated, I can't imagine that oil could be cheaper for you than even a standard electic resistance water heater. Are the rates you stated just the cost of electricity or does it include all the other b.s. in the bill (delivery charges, taxes, etc). For comparison's sake, I just take my total month's bill and divide it by the # of kwh billed.

Here's a link to some info on heat pump water heaters that may help you:

http://www.greenbuildingadvisor.com/blogs/dept/musings/heat-pump-water-heaters-come-age

 

[maple1]

Excellent information. From what I can see, I don't have any sort of storage for the hot water, so I'm assuming my furnace heats it on demand?

That sounds like you have a tankless coil (coil inside the oil boiler). That isn't on demand - the boiler maintains a certain temperature 24/7, and it is the most inefficient way to heat hot water there is, that I know of. That's the way mine used to be. I now have a regular resistance electric hot water tank and burn no oil at all anymore.

 

[jcleary47]

I know that when I turn my water on, it takes a few minutes and I'll get the hot water, and after a few minutes of running it, I hear the furnace kick on. I'm assuming this is because it ran out of the small amount of water it had ready to go that it's been maintaining and needing to heat more. It doesn't necessarily kick on right away when I call for hot water that I can tell anyway. There's a small water expansion tank thingy right above the furnace, not sure if that's a mini water storage thing or what.

 

[Chain]

I hadn't heard of that. Do you have any specifics?

Scrap that idea....Liquified natural gas is not available for residential use, only as a means of shipping huge quantities of natural gas overseas. Picture large ocean going vessels with huge round containers on board filled with liquified natural gas. See here:

(broken link removed to http://www.naturalgas.org/lng/lng.asp)

 

[velvetfoot]

That's what I thought. It's too bad this whole fracking thing couldn't lower the cost of propane.

 

[woodgeek]

I know that when I turn my water on, it takes a few minutes and I'll get the hot water, and after a few minutes of running it, I hear the furnace kick on. I'm assuming this is because it ran out of the small amount of water it had ready to go that it's been maintaining and needing to heat more. It doesn't necessarily kick on right away when I call for hot water that I can tell anyway. There's a small water expansion tank thingy right above the furnace, not sure if that's a mini water storage thing or what.

The boiler itself contains a considerable mass of hot water, with channels through it for the hot gasses from the oil flame to transfer the heat. There is a big copper coil immersed in that water mass that your DHW flows through. At the faucet it starts cold cuz the pipes in wall are not heated. The boiler is hot all the time, usually very poorly insulated (and you can't safely add a blanket either), and will burn 150 gallons a year even if you use no DHW or space heating. The exp tank does not store any heat.

While the 'waste' heat is helping you heat your house in the winter, it is also heating your house in the summer, potentially making things less comfortable. Even in my warmer climate more than 50% of my AC bill was actually pumping this waste heat out. My neighbor has a similar house and still has his boiler, and I hear his AC coming on when it is 60°F outside. Oil boilers suck.

 

[jcleary47]

Great information. So if I were to install an electric hot water heater, would I typically want to shut the furnace down in the summer when I definitely don't need it?

I'd probably want to keep it on in the winter unless I find another option for heating the room above the garage, but like I said I try to just keep it at 45 since it isn't used.

But I guess if I'm leaving the furnace on in the winter for the purpose of heating that one room up to 45 degrees, it's still wasting energy because it's keeping water warm even when it isn't needed as long as it's on.

 

[woodgeek]

It gets worse....most older boilers are made out of cast iron....and cast iron can rust. This is seldom a problem if the boiler is hot...the flame side stays dry and the wet (inside) surface has no oxygen. If you shut it down, it might corrode, shortening the life or causing it to spring a leak.

You might have thought a pressurized water filled boiler would be a welded steel tank....nope, usually just hunks of cast iron hammered together (essentially press fit) until they don't leak (much) and then bolted. Those joints in the cast iron can be unreliable when thermal cycled, corroded, or left cold for long periods. IMO a lot of small leaks are sealed by little more than water 'lime'.

OF course, maybe I'm a worry wart. Lots of folks turn their old cast iron boilers off all summer. And a small number of those boilers fail prematurely, sometimes by flooding the house--they are hooked up to your cold water supply to 'auto refill' if there are small leaks, this will be like running a faucet on your floor if your boiler fails.

So, unless your boiler is stored next to your priceless art collection....turn it off for the summer, and turn off its water supply while you are at it. And then keep an eye on it.

 

[woodgeek]

Great information. So if I were to install an electric hot water heater, would I typically want to shut the furnace down in the summer when I definitely don't need it?

I'd probably want to keep it on in the winter unless I find another option for heating the room above the garage, but like I said I try to just keep it at 45 since it isn't used.

But I guess if I'm leaving the furnace on in the winter for the purpose of heating that one room up to 45 degrees, it's still wasting energy because it's keeping water warm even when it isn't needed as long as it's on.

For one room over a garage, you could just put in electric baseboard. Whether that would be cheaper to operate on a cast per unit energy basis is hard to say.....but in my parts the annual maintenance on an oil boiler is close to $200, which is alot for an appliance that just heats one room.

Of course, you might still want to keep the boiler for backup on the pellet stove, to use when you go out of town for awhile and can't feed the pellets, for when the pellet stove can't keep up, etc.

 

[jcleary47]

I don't know if 7 years is old for furnaces but I'm hoping it won't cause any issues. I'd probably have my buddy who's a furnace guy help me out with installing this if I end up pulling the trigger on a water heater so maybe he can take a look and let me know if there could be any implications with mine. I appreciate all the advice!

 

[maple1]

How much oil do you burn in a year now?