"So, Which Is Cheaper - Gas Or Electric?"

As a home inspector I get the question all the time about appliances - we'll be looking at the dryer or water heater and they will ask, "So, which is cheaper, gas or electric?"

There are many places and sites that you can go to in this investigation.  And it depends on where you live! 

Electricity in some regions is much cheaper than in others.  And gas overall has come down over the years.

One place I saw the bureaucrat actually said to check to see if you live in an all electric house or neighborhood before you purchase a gas appliance!  Uh, um, okaaaay...

And, when this refers to gas, it means natural gas.  There was no where that looked specifically at liquid propane gas appliances, although the propane market does vary somewhat in price like natural gas.  But overall, the natural gas price usages would likely apply to LP.

One place that seems to investigate everything energy related is a fellow named Michael Bluejay.  I don't know if that's his real name, but his site is complete.  I include him here so I don't get accused of ignoring the environmentalists!

Water Heaters

You have to look at water heaters in terms of Btus (British Thermal Units).  A gallon of water weighs 8.33 pounds.  If the water coming into the house is 60F and you want to raise it to 125F, that's a 65 degree F rise.  So how many Btus does it take to do that?     8.33 x 65 = 541 Btus per gallon.

So, an electric water heater averages 93% efficiency.  So 541 Btus divided by 93% efficiency = 582 Btus to heat a gallon of water.

One kilowatt hour is 3413 Btus, so one Btu is .000293 kilowatts.

Then 582 Btus x .000293 kilowatt hours = .17.  Further, if you have a 50 gallon tank then .17 x 50 = 8.5 kilowatt hours to heat a 50 gallon tank of gas.

My electricity costs me $.09 per kilowatt hour, therefore it would cost me .09 x 8.5 or $1.45 to heat 50 gallons.

The typical gas water heater is 59% efficient.  And doing the same math it takes 890 Btus to heat a gallon of water.  Using the same formulas as above and using my gas cost of $1.032 per therm, it costs $.60 to heat a 50 gallon tank of water.

Comparison:  ELECTRIC costs $1.45 to heat a 50 gallon tank vs. GAS which costs $.60 to heat 50 gallons.

Your costs will vary if your electric or gas rates vary from this example!  But still, gas water heaters cost less than half.

Interestingly he also compares the tankless water heaters.  He says the same thing I said in a blog about them over two years ago!  His words:  "the energy savings are meager, and the payback time could easily be 20 to 40 years."  (Remember, they don't last that long.)  Further, "tankless water heaters promote water waste, are more likely to break down and are more expensive to repair when they do break."  So there!  A little more, "Electric tankless units cost as much or more to run than large gas tanks."  He calls the tankless heaters "hype," and I called them "fabled."

Dryers

Consumer Reports compared a typical household large-load electric dryer to a large-load gas dryer.

That would mean a 22000 Btu dryer for gas versus a 5.4KW dryer for electric.

Their numbers?  Using national averages for gas and electric usage, they determined this:

Comparison:  ELECTRIC costs $.95 per load vs. GAS which costs $.23 per load.

Once again, your rates may vary, but gas dryers cost around 1/4 of an electric dryer.

Kitchen Ranges

Using Energy Star information, which ranks appliances depending on energy savings, they compared typical kitchen range costs using gas versus electric.

They compared cooking time of one hour at 350 degrees F.  An electric oven needs 2 KW to do that, and a gas oven 0.112 therms.  Using the same national averages for costs they arrive at this:

Comparison:  ELECTRIC costs $.14 per kilowatt hour or $5.94 vs. GAS at 100 Btu which costs $2.34.

And even if your rates vary, a gas oven costs less than half of electric.

My recommendation:  do your homework!  If I can do this you can.  Go to different sites and see what you can see.  But when you make your decision, remember, with current information and technologies, the United States alone has enough natural gas to last 92 years.  And in the world another 100 years above that.  So, your gas appliances are likely to have fuel for a while...