kwh compared to therms? (gas or electric hot water)

[mikeyny]

Since I preheat my domestic hw with a home brew heat exchanger I wonder if I would be better off using an electric water heater. Presently I have a separate 50 gal tank that the cold water enters, when the wood boiler is running it makes hot water thru my heat exchanger. (5 ft of 2inch black iron pipe with 1/2 inch finned copper running thru it) and that feeds into my gas water heater. My nat gas bill varies from 5 to 17 therms per month. 17 therms is about 38 bucks. I was wondering if it would be better (cheaper) to use an electric water heater, since there would be no standby looses. When I googled a therms to kwh calculator it says 17 therms equals 498 kwh. Is that correct? IF it is gas is much cheaper in my area. Any thoughts.
Mike

 

[ewdudley]

Check out hearth.com fuel cost comparer, it normalizes each popular fuel to dollars per million btu:

https://www.hearth.com/econtent/index.php/articles/fuel_cost_comparison_calculator/

It lets you take efficiency into account, but I don't think there's a way to specify a constant rate of standby loss, you may have to type it all into a spreadsheet for that.

(Yes 17 therms is 498 kWh.)


--ewd

 

[woodsmaster]

I believe in most places gas is currently cheaper than elec. Not so a few years ago and who Knows what the future holds.