Hot water, electric vs. natural gas.

[Volvo farmer]

I recently got an almost free 20 gallon electric hot water heater. It has a single 1500W 120V element in it. I heard natural gas might go up as much as 40% this winter and was thinking about putting this electric unit in the crawlspace and plumb it in before our natural gas unit. My thought is that I could delay the gas unit coming on for the first ten gallons or so of hot water but I'm having a hard time figuring out at what point it becomes cheaper to heat water with electricity.

We have a time-of-use meter and I would only be heating water with electricity at $.04/kwh with no rate increases projected in the near future. Natural gas is currently $.82/ccf, but will likely be up over $1.00 in the coming months.

I've called the electric company, called the gas company, looked on the internet, etc but can't really figure out a way to calculate this. Is there a way to compare a KWH to a CF of gas in terms of how much water you can heat with it?  I realize this is going to be imprecice because of heat up the gas chimney, etc, but I have been unable to find any ware to compare the two sources of energy so that I can do a dollar to dollar comparison.

Any ideas?

 

[pwr]

A CF of natural gas has an energy content of about 1030 Btu.  That translates to 0.3 kWh.  How much heat from the gas will be lost up the chimney is a quess, but maybe 50%, so assume 6-7 CF of gas will do the same as a kWh.

[jomoco]

Hey Volvo Farmer,

.04 cents per KWH sounds pretty reasonable to me. I pay over 3 times that here in California, I'd go for it!  I know that doesn't answer your question but .04 cents per KWH man that's cheap!

jomoco

[henjulfox]

Volvo,

My thought is to go down to the local home improvement store and look at those big

yellow stickers on the front of the water heaters. Compare a gas and electric model

of similar capacity. I believe the stickers have the price per KWH and therm so you

can adjust for your actual rate.

I did the math many years ago - gas was a lot cheaper but electricity hasn't gone up

much since then and gas has.

-Henry

[pyrocasto]

$.04 /kwh? That's half of what I pay and I thought mine was pretty decent. I'd stay electric that way, because gas seems it will be a bit more.

[Volvo farmer]

Thanks everyone.

$.04/kwh is only at certain times of day with a TOU meter. the rest of the time I pay $.12. And I didn't figure in the $12/mo it costs me even if I don't use a single KWH. Gas is no better, $10/month just for the privilege of having a meter in my yard.

Hoping to get out of here and into the off grid house in about 12 months. Then somebody else can pay the $12 and I'll have an extra $144/year to invest in solar!

[wooferhound]

We are discussing this subject in the  2005 / 2006  timeframe. But if we were talking about this in 10 years, I believe that Gas prices will increase very much more than Electricity prices.

I moved into this house a year and 2 months ago. At the time I was quite happy that I had Gas heat here, But now it scares me . . .

[GaryGary]

Hi,

This is just a thought.

If you take your extra hot water tank, put it inside of an insulated box that is glazed on the front, and put it outside facing south -- you end up with a batch style solar water heater.  Free fuel!

Batch solar water heater plans here (also free!):

http://www.builditsolar.com/Projects/WaterHeating/water_heating.htm

Look for "Batch Water Heaters"

Gary

[Gary D]

Here in Pennsylvania, natural gas prices are going up 48% this weekend. Since most peak power electric plants are gas fired, I'm sure we'll get hit with a fuel surcharge that matches... so it wouldn't matter if an electric or a gas unit was used, they'll get you in the end. (no natural gas here except man/ dog made 8-/)

[elvin1949]

My experence

elvin

[elvin1949]

My experince is that it depends on how you use hot water.

 I live alone so electric is cheaper for me.

.06 cents a kwh for electricity , $2.25 cents a gallon for propane.

pilot light uses 5 gallon's of gas a month.

that is $11.25 plus tax just to be ready to heat water every month.Only $6.00 for the meter for electric.

 Louisiana is hot in the summer [92 degree's today].

Only cool in winter [most of the time].

 I put a blanket on the electric heater and end up

paying about 1/3 as much for hot water as on gas.

later

Elvin

[henjulfox]

I had a 40 gallon batch heater as you describe in a previous house plumbed as a pre-heater for my electric tank. Would get over 100 degrees on a sunny day. I bought the tank new and still calculated the payback as around a year. Best investment I've made. Current house has no southern exposure or I'd build another.

-Henry

[nothing to lose]

"$2.25 cents a gallon for propane. pilot light uses 5 gallon's of gas a month.

that is $11.25 plus tax just to be ready to heat water every month"

 I have to disagree with you on that, unless somethings wrong with your pilot light.

I use a 20lb propane tank to run my cook stove, stove has 3 pilot lights, 2 on top, 1 for oven, and we do allot of cooking durring the month. We never fill the 20Lb tank more than once a month and I think that is actaully less than 5gal of propane in that tank. Depending how much we cook I think it's about 5 weeks or much longer between fills. Longer durring hot summer when we cook less and about 5 weeks maybe when we cook allot more in colder winters.

If for sure you are using 5gal amonth just for a pilot light then you should see if it needs adjusted down, perhaps it's burning like a torch?

[nothing to lose]

The more insulation on your tank the less heat it will loose. Reheating water that has cooled while sitting over night etc.. is very wasteful. Electric tanks you can pack around all you want, gas you need to be careful of, do not restrict airflow to the burner or get it too close to the fire under or vent above.

I don't know why I don't see much insulation on hot water pipes? Insulate those suckers too. If you run hot water and the pipe gets hot to the touch you are losing heat there!

 Most people mix hot and cold water at the sink or tub anyway, so the hotter the water is when it gets there the less hot you can run and the more cold you can run, cold water does not cost anything to heat.

Adding a stripped down tank in the water supply before the hot water tank almost always helps if you have the room for it. Room tempature water is almost always warmer than that from a well or city mains so it takes less to heat it.

If you have both an electric tank and gas tank then you can choose which to run when

If durring the winter propane sky rockets turn off the gas water tank, well insulated it should hold heat for a very long time so it can be extra storage of the electrically heated water. If electric goes up and gas falls come summer, fire up the propane heater and shut off the electric one. The electric tank can then just sit in the line before the gas heater doing nothing.

Install a bare tank before the other 2 as a preheater.

I often wonder why I never see any copper tubing on the vent pipe above a gas water heater? There is allot of wasted heat going up that pipe, why not wrap a copper water pipe around it to colect what ever heat you can before the water enters the tank.

 Don't restrict the vent causing fumes to build in the house, but I don't think stealing a bit of heat would cause any problems either.

 Most the time when I get scrap water tanks the only thing wrong is they were never cleaned and full of sedimant. Most never leak, though I have had a couple and it's rare. I take all the free tanks I can get normally and sometime even buy them from the scrap yards. Most have fittings, valves, pipes, and brass hardware still on them.

Sort of a small gold mine for $3

Cleaned out the tanks are useful for many things including preheaters when striped down. If clean the fiberglass insulation wrapped around them is great for insulating around hot water tanks in closets, pipes, and other things.

[elvin1949]

NTL

 The pilot was as low as it would go.

After i got rid of the water heater,

i made a change to the cook stove to.

 Like you my stove had 3 pilots,5 gal would last 4 to 5 weeks. I took it out and put in a 3 burner

counter top unit from a camper,no pilot's no oven.

I use a coleman camp oven to do what little baking i do [on said stove ].

 It was installed march 01/05 with a fresh 5 gal bottle of gas. It ran out last night-7 months and 4 day's.

BIG difference between with and without pilot's.

later

elvin

[nothing to lose]

Yea I agree pilot lights are a waste of gas. I hate them too because you basically have 3 candles burning creating heat while running the air conditionare to cool the house.

 If I could do away with my pilots I would, but I don't think a tank would last us that long still any way. We had a stove without pilots before and a tank lasted a bit longer, but then again the oven did not work and we did not cook as much then either as we do now. I think then a tank might have lasted 3 months for us perhaps.

Still, though wasting gas I don't think a water tank pilot light itself should use much all by itself.

[energydoctor]

Your time of day meter is excellent.  What I tell you no environmentalist or utility will tell you.  I am an electrical engineer.  Install a capacitor bank at your main breaker panel.  You can save up to 22% on your total electric bill.

They are called Power conditioners because no one knows what a capacitor bank is.

They improve the Power Factor which lowers the electric bill. You can buy one at

www.abetpower.com  Advanced builder energy technologies.

Also install a Powerkuff for less than 20 dollars.  It will save you an additional

10%.  Buy them at Energybuddy.com

Lastly whether you have gas or electric hot water tank you can turn off both of them and hook up a heat pump addon heater that attaches to the plumbing line and heats your water from the ambient air in the basement and stores in your existing non working tank.

An electric hot water tank uses 4500 kilowatthours a year.  A addon heat pump for hot water uses 1485 kilowatt hours a year.  The capacitor bank and the powerkuff  will lower that an additional 30% to 1039 kilowattshours per year.

Add on low flow showerheads and faucet aerators at Bricor.com and USALandlord.com

and you will lower it even more.

The addon heat pump water heater is available at Nyle Special Products and is called the Nyletherm 110 and uses 110 volt oulet, 240 volts is not needed. Lastly for 2006 and 2007 get a 300 dollar tax credit if you buy one off your federal taxes.

Do what I say and you will never want gas again.

Don't forget to change the anode rod on either tank to stop them from rusting.

Cost about $21 per tank