Any HVAC guys here, I have question

[Gun guru]

I am thinking that with high cost of Propane, Prebuy is $2.50/gallon according to the woman at my propane supplier. Would an electric water heater be the way to go?
My Kilo-watt rate is 11.4 cents per kilowatt hour that is with all taxes and fees included in the bill, I had the wife look up our Edison account and it gave us all the power used for the last several months and every month works out to 11.4 cents/kilowatt hour.
I am thinking that if I have an electric water heater I will likely use $1.60 per day in electicity that is for 4 showers per day and running the dishwasher.
My main question for an HVAC guy is---Is an electric water heater more efficient then a Propane one when Propane is $2.50/gallon. And how much propane does a water heater use in a given day if it runs for 1 hour?
Thanks.

 

[JDemaris]

You're at the break-even point. Not much gain or loss either way.

Electricty gives around 3400 BTUs of energy per 1 KWh. That comes to .00003 of a cent per BTU.

Propane gives around 91,500 BTUs per gallon.
That comes to .000027 of a cent per BTU - but the propane has some heat loss out the vent pipe.

 

[RobMD]

I know a lot of people would go tankless these days if they had the money for the system. The engergy savings by using tankless systems heated by propane are phenomenal. An electric heater has to continually maintain 120* or whatever setting its on - no matter if the unit is being used or not.

 

[Gun guru]

2 other things that would maybe make the electric water heater better is that I wont have to waste propane to keep 50 gallons of water ready for use and I wont have to listen to the high eff. water heater that I have now.
thanks for the input.

 

[Gun guru]

2 other things that would maybe make the electric water heater better is that I wont have to waste propane to keep 50 gallons of water ready for use and I wont have to listen to the high eff. water heater that I have now.
thanks for the input.

 

[Anonymous-0]

Propane = 91300 BTU per gallon.
Assume 80% efficient water heater
73040 BTU of water heat per gallon
or 73040 BTU per $2.50
Therefore 29216 BTU per dollar

Electricity = 3413 BTU per KWH
100% efficient

3413 BTU per 0.114 dollar
Therefore electric gives 29938 BTU Per dollar

A propane water heater will have slightly worse
heat loss (than electric) when not running, due to to the flue running up through the tank. This isn't a huge effect, maybe another 5%. Propane would allow a smaller tank size, due to its faster recovery rate, so the smaller tank could compensate somewhat for the flue loss.

Bottom line is the cost of water heat is about the same either way, with perhaps a slight advantage to electric.

In my opinion it does not yet make economic sense to buy an electric water heater to "save money". Your payoff for the capital investment would be very long at the nearly insignificant difference in operating costs.

 

[JDemaris]

A tank heater - if it's well insulated - doesn't use much at all keeping itself warm.

I know of many tankless installations, and the gains if any were minimal. The one big advantage to a tankless - is in a house with several places that need hot water that are far from the one cental tank heater. In that situation, there's a lot of heat loss through long runs of pipe. In that sort of case, several small tankless heaters at each location can make a difference.

 

[HENRY E NC]

As an HVAC Man I would advise you to investigate the instant hot water heaters that heat on demand by electric.Some of these programs have rebates from the power companies. Check on that. Propane prices are tied to oil as it is a product of oil fracking. As the price of oil goes up so will the price of propane. Electric power has the better chance of stabilizing due to wind, solar, coal and nuclear power. Just my own theory. Henry

 

[RobMD]

They make a water recirculating pump to bring hot water to the furthest run of pipe. I imagine this is only to save water, not energy costs.

 

[Anonymous-0]

Think of this --- Quality of Water is very important -- if the ph is less then 7 -- how are you going to keep the tankless system clean ??

 

[buickanddeere]

Even if the costs are break even. With electric there is no LP tank sitting in the yard to look at. And no risk of gas leaks. No flue, no birds nests, no flame/combustion in the house and no carbon dioxide or carbon monoxide worries.

 

[Anonymous-0]

Additionally the HW tank has a thermostat and you don't need boiling water or 180 degs to be comfortable, in OZ they are telling people to reduce the temperature in the HW taps so as to avoid Children being scolded.
We also have an off peak rate[reduction] for heating during the early morn.

 

[dave guest]

As an electrician in Mich., I get dept of energy letters. Last one I saw stated 50% more money would be spent heating water with propane. Check latest numbers with your state.

 

[dave guest]

As an electrician in Mich., I get dept of energy letters. Last one I saw stated 50% more money would be spent heating water with propane. Check latest numbers with your state. My furnaceman buddy says electric hot water no brainer and forget tankless.