Should I Switch From Oil to Electric HW

traderfjp · Post by **traderfjp** » Thu. Jun. 05, 2008 7:17 am

I have a Channing 3 stove and it heats most of my house. I already have a large coil inside my stove that runs through the boiler and heats a basement very well. Currently I'm using about 25 gallons a month of oil which is about 100.00 for hotwater. I have a Bock oil fired hot water heater. I love the reovery rate and we never run out of HW. I have 4 people in my home (3 adults, 1 teen). I was thinking about installing a 40 gallon electric HW heater instead. I live on Long Island with the highest rates in the nation. Would I save any money doing this? Any advice.

CoalHeat · Post by **CoalHeat** » Thu. Jun. 05, 2008 9:05 am

I don't know exact numbers, but heating water with electricity is the most inefficient method. The recovery rate is very slow, I can say with 100% certainly you will run out of hot water on a regular basis with an electric HW heater. I switched from electric to an Aero oil-fired in 2002. Huge difference. At the time my electric bill dropped $50/month.

Also, if there is any Calcium Carbonate (hardness) in the water the tank with begin to accumulate deposits on the elements which will slowly fall off and begin filling the tank. Once the lower element is covered it's good bye. I had the electric unit before I installed a water softener, every few months I had to drain the tank, clean the elements, and stick a thin pipe into the tank through the element mounting point to try to suck out the deposits with my shop vac.

There's a long run from the heater to the kitchen sink, I do have a 5 gal. electric heater under the sink connected to the hot water line which provides instant hot water at the faucet. It doesn't operate very much since hot water feeds it. That's about as far as I will go heating DHW with electricity.

My vote is to heat DHW with coal, either 100% or with a loop or coil in a coal stove/boiler.

Sting · Post by **Sting** » Thu. Jun. 05, 2008 9:32 am

Boy I really hate to stick my toe in front of a tenured poster but may I please disagree that electric DHW is the MOST inefficient!

There is no energy lost in electric DHW production as the resistance heaters are submerged directly into the vessel and no energy is lost " up the stack"

Usually a therm of resistance produced heating energy is more expensive - but that simply a fact that purchased watts of power aren't as cheep as therms of heat produced via other fuel.

Standing a 40 gallon tank of DHW only costs a few dollars a month.

Its the cost of raising the temperature of street water to 120 degrees that takes money (energy). If you DHW use does not decrease - your cost of any DHW production appliance will also not decrease. Switching only makes "cents" if you can increase appliance efficiency by replacing an old inefficient unit.

traderfjp · Post by **traderfjp** » Thu. Jun. 05, 2008 10:40 am

I agree that electric HW heaters are not the best for recovery. OIl is the best for recovery and then NG. I'm sure someone could design an electric HW heater with a good recovery rate but it would probably cost a fortune to run. If the showers are staggered I don't think we would run out of hot water. My mom has electric in Florida and we do sometimes run low on HW but her tank is 15 years old, has never been drained and is on a timer to save energy. With a 40-50 gallon tank I think we would be OK. I just want to be off oil. An electric heater is about 200.00 and my Bock oil fired tank is about 16 years old so I'm due for a replacement. If it was costing you 50.00 a month for electricity in NJ it'll probably cost me about 75.00 in NY. To save 25.00 - 30.00 a month I would rather stay with oil but if prices go much higher I guess I'll look at this again.

Right now I use coal for most of my heating. I have a custom coil that runs boiler water through it. I keep the aquastat at its lowest level and the water form the coils run into a storage tank and then into the boiler where it makes a giant loop and heats my basement-the coal stove does all of upstairs. I use a bronze circulator to move all the water around. The coil was custom made and has about 48 feet of pipe coiled in it. This system works well and the boiler rarely turns on unless it gets really cold. I was thinking if I could somehow steal the HW that is feed from the coils into the storage tank which then feeds the boiler I could save some money. We only shower twice a day so it isn't a big draw. The problem is that you are not suppose to let air into a heating system. Is there anyway to do this. I also filter all my water so any sediment, etc would be filtered out. Thanks

billw · Post by **billw** » Thu. Jun. 05, 2008 10:51 am

What I did was put the electric water heater in series with my DHW coil from my oil boiler. The input to the electric water heater was already hot. We never ran out of hot water even when all three of my kids were teenagers. That was when energy was inexpensive so I wasn't to concerned about costs. With my new coal upgrade this summer I'm not sure how I'm going to handle my hot water needs. I thought of replacing the electric water heater with a boilermate but those things are really pricey. The payback for that purchase would be to long. I may just keep what I've got.

Yanche · Post by **Yanche** » Thu. Jun. 05, 2008 12:16 pm

Heating almost anything with electric resistance is close to 100% efficient. It however is not economical. Don't confuse efficiency with economy, they have very different meanings.

traderfjp · Post by **traderfjp** » Thu. Jun. 05, 2008 12:58 pm

What is a boiler mate?

I have coils in my boiler that aren't being used I thought about running my oil fired HW heater's water through those coils. 1. The hotwater heater which is more effecient to run then my boiler would help to keep the boiler up to temp and any extra heat would be used to heat the hotwater in the tank for domestic. I would also be keeping the domestic and boiler water seperate.. I'm not really sure if I would gain much doing this. The water in my boiler never gets hotter than 140 degrees unless the heat is off downstairs (boiler and coil only run the basement heat) and then the water gets to about 160 but usually the heat is on constantly since the water coming from the coils only gets the inside of the boiler to around 130.

Post by **Richard S.** » Thu. Jun. 05, 2008 1:20 pm

There's a digram and description of using a hot water loop combining your coil and hot water heater. Basically the hot water heater will become a glorified storage tank unless you use a lot of hot water.

https://coalpail.com/coal-heating-encyclopedia/do ... water-coil

This article could use some help, I believe Yanche mentioned using a specific type of check valve... Could probably use a few other setups as well, some have used pumps instead of letting it naturally flow.

Matthaus · Post by **Matthaus** » Thu. Jun. 05, 2008 1:23 pm

traderfjp wrote:What is a boiler mate?

http://www.amtrol.com/boilermate.htm

As you said the oil fired DHW heater is better to run than trying to keep the boiler hot plus the losses that would be incurred with a heat exchanger.

CoalHeat · Post by **CoalHeat** » Fri. Jun. 06, 2008 7:14 am

Yanche wrote:Heating almost anything with electric resistance is close to 100% efficient. It however is not economical. Don't confuse efficiency with economy, they have very different meanings.

Thanks for the explanation, I agree.