utility costs.

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looking at the gas water heater vs.elecrtic WH thread -- utility costs are a large factor in people's decision.one poster states he pays 17.7c/kwh. for hydro. what are the utility costs in different regions ? i pay 19.9 c/cu.m. for gas; 5.8 c/kwh. for hydro; 26.6 c/cu.m. for water. thanks for any replies.
 
It will be a tough conversion. We sell it by the cubic foot here in the states...

$0.62577 per cubic foot for natural gas this month, it varies widely.
 
Eastern Iowa, US currency:

Natural gas, 65 cents per 100 ccf, conveniently this is also almost exactly 100,000 btu for purposes of calculations.

Electricity, 11.18 cents per KW. With 3413 btu per kilowatt, this would cost $3.27 to produce 100,000 btu of heat.

Of course the efficiency of the appliance could vary greatly - ground source heat pumps are effectively more that 100 percent efficient, gas water heaters have quite a bit of loss up the center chimney and none of the forced induction water heaters seem to use a condensing cycle, so are not much better than the cheap ones.

Does anyone know of a water heater with a secondary condenser? the specs for gas water heaters seem to indicate that none are above 70 percent? Electric water heater efficiency is close to 100 percent - and there are heat pump models. They would be great in Florida when you are using free heat and even taking the load off your central air, but up north they just pick up heat that you are already paying for!!
 
Quote:
gas water heaters have quite a bit of loss up the center chimney and none of the forced induction water heaters seem to use a condensing cycle, so are not much better than the cheap ones.

Does anyone know of a water heater with a secondary condenser?


Help me out here. Are you talking about some "economizer" to recover more of the waste heat?

Run the cold water supply through a coil inserted into the exhaust plumbing.
 
Yes, you have it exactly. All the new high efficiency furnaces use a secondary heat exchanger, the exhaust gas is cooled to nearly room temperature. Of course this results in LOTS of condensation, the secondary exchanger puts out lots of water that is sent down your drain. I know of no water heater doing it though.

Sending hot exhaust up the chimney seems stupid, but there is lots of water in the exhaust due to the combustion. Remember hydrogen and oxygen combine to form water!! Furnaces with secondary recovery are about 20 percent more efficient than standard flue exhausts. The downside is of course you must use a very small "inducer fan" to push the air through the system, as the cool exhaust will not make a chimney draw.
 
Originally Posted By: fsskier
Eastern Iowa, US currency:

Natural gas, 65 cents per 100 ccf, conveniently this is also almost exactly 100,000 btu for purposes of calculations.



There isn't much of a cost savings to be had for a small family.

There are only two people in our home, so ratio these numbers to fit....

During the summer we use natural gas for clothes drying, hot water and cooking. Our house heat is off for about 5 or 6 months. Our natural gas consumption runs 12-14 therms/month during that time. A therm is 100,000 BTU so it's about 12-14 x100 cu ft. Let's guess and say 10 therms of that is for water heating. At your rates, that's $6.65/month for hot water. A more complex and expensive water heater with a secondary heat exchanger might save 20% of that, or only $1.33/month.

That's likely why there aren't more uber high efficiency water heaters on the market.
 
A quick search of water heaters shows that condensing units are now available! That shows how long mine has lasted, there were no condensing units when I put it in, well over 10 years ago.

Yeah, the payback would be slow, our summer (gas water heater and gas dryer) bills range from $4 to $ 9 a month. If the "best" water heater ran for free and cost $1500 installed it would take 20 years to pay for itself!!

I have always done everything myself, even though installing the last gas water heater took about 6 hours as I was changing from electric to gas. Thankfully, while the wife was complaining about having no water for half a day, a letter arrived from our daughter, living in a remote jungle village in Africa. It seems the elephants had come through and trampled the water pipes further up in the mountains, and she would have no fresh water for many months!!

All the complaining stopped.
 
Quote:
Yes, you have it exactly. All the new high efficiency furnaces use a secondary heat exchanger, the exhaust gas is cooled to nearly room temperature. Of course this results in LOTS of condensation, the secondary exchanger puts out lots of water that is sent down your drain. I know of no water heater doing it though.


It would be expensive and would not be UL approved, but you would just run the exhaust of one unit into a second unit above it ..use induced draft on that unit. You should be able to get the second unit, minus the heating array, for somewhat less. Route cold water supply to the top unit to feed the lower unit.

It would take some MacGyvering to make it tidy ..but not too much to make it safe.

The simple coil in the outlet ducting would recover the heat, but it wouldn't have the insulated storage that a separate partitioned exchanger would have.
 
I do not mean to hog this thread but.....
a quick review of the condensing units seem to show that only the "on demand" units have that feature.

Anyone know of a tank type with secondary recovery?
 
Oooops ..yeah ..sorry.


$0.185/kwh plus all types of fairytale costs (meter charge = account charge- stranded asset charge - distribution charge - CEO bonus charge - and assured no risk ROI on a captive audience charge) for 24/7 on demand power.

$0.057xxx for interrupt-able service (contact drops out at the meter) that's variable depending on if they can sell power on the grid. It's also assigned all of the fairytale costs

No clue on NG per decatherm or cubic foot with thermal factor.

Water and sewer was used here as a major revenue generator that allowed the appearance of no property tax increases ..bringing the borough costs to the end user. Sewer costs are 300%+/- of the water costs. There's also minimum fees based on single or multi-unit and the size of the service for commercial or industrial. It's as complicated as rating an industrial outfit for what they're going to be charged for electricity (line capacity charge ..etc.)

Single dwelling with family of 4 = $150/quarter - includes trash removal. Multi-unit works out to more than that per unit regardless of actual usage on the property. The base fee is $100/quarter/unit.
 
I don't have the prices handy, but heres something I found amusing. Our city water utility pays us to waste water.

Our water rates are tiered. Summer rates are based off of average winter consumption, and start going up when you use more than 10% extra in the summer. The highest rate is around 10x the cheap price tier.

Since we water the lawn, I figured out I could save $100 a year if I wasted 20,000 gallons in the winter (and save a bit more if I wast 30,000 gallons). I was going to do it, but my wife objected. So instead we drilled a well a in September. Now we'll water the lawn even more in the summer.
 
yeti,
$10/month to be hooked to the grid, and 17.7c/kWHr
$10/month to be hooked to the gas supply $0.01681/MJ (drops to $0.01575 after 5485MJ)
 
Originally Posted By: fsskier
Does anyone know of a water heater with a secondary condenser? the specs for gas water heaters seem to indicate that none are above 70 percent? Electric water heater efficiency is close to 100 percent - and there are heat pump models. They would be great in Florida when you are using free heat and even taking the load off your central air, but up north they just pick up heat that you are already paying for!!


Saw an article where a bloke ran the cold water supply to his shower through the shower waste water outlet, over a distance of around 10-12 feet.

Intent was to pick up as much heat as he could, using the greatest temp difference he had.

For a family of 4, it made a notable difference in his gas consumption (tanked propane).
 
Originally Posted By: Shannow

Saw an article where a bloke ran the cold water supply to his shower through the shower waste water outlet, over a distance of around 10-12 feet.


That technology isn't new and it's not a bad idea.
When I was growing up on a dairy farm, we had a heat exchanger setup for our cows. The milk in the milk holding tank was cooled by the cold water that went to the cows' drinking fountain and the water that the cows drank was warmed by the heat from the milk cooler. (Milk cows drink a lot of water and extremely cold water gives them a "brain freeze" similar to what humans experience)
 
I can't believe how much the prices differ across the country. That's more than gasoline! Natural gas in not billed by cubic feet, it's billed by the therm. 1 therm = 100k BTU. Exact cubic footage can be more or less depending on the gas quality.

I pay about $1.40/therm and $0.10/kwh. That's with all the extra fees calculated in. Oddly enough at my shop, with the same electric utility, charges me 11-something cents for the "industral" rate. Why would the industrial rate be more expensive?
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Due to the fact that I sleep most of the day and stay up all night, I'm going to change my electric plan to "time of use" metering, where I pay 12 cents/KWH for "on peak", when I'm sleeping, 8 cents for "mid peak" and 4 cents for "off peak". All day sunday and holidays are considered "off peak".
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Originally Posted By: SecondMonkey
All day sunday and holidays are considered "off peak".
grin2.gif



Believe it or not, on Sunday and Monday mornings really early, Australian coal fired power stations have to pay the grid to take electricity
 
Originally Posted By: Shannow
Originally Posted By: SecondMonkey
All day sunday and holidays are considered "off peak".
grin2.gif



Believe it or not, on Sunday and Monday mornings really early, Australian coal fired power stations have to pay the grid to take electricity


Yeah, I've heard the startup costs are very high. Around here much of the water comes from hydroelectric, so they can just close the dam and keep the coal fired plants on full blast.
 
Quote:
Oddly enough at my shop, with the same electric utility, charges me 11-something cents for the "industral" rate. Why would the industrial rate be more expensive? confused


You're very lucky not to be in PECO country. You would pay capacity charge for your potential full load to the distribution. Your rate would also vary depending on what you use it for. You would also pay "surge" factors. That's where your maximum ONE TIME peak draw would alter the rate of your usage for the entire month. So you happen to use your arc welder while the heater turns on ..and you switch all the lights on at the same time and start a pot of coffee in the office ...you'll pay more than if you did them progressively one at a time. Not to mention power factor correction for any inductive or harmonic loads.

I've been waiting for the equivalent of "shop supplies" and "disposal fees" on the itemized bill.

We don't get time of day metering. We have to run hard wired dedicated meters that physically drops out and cuts you off. Separate meter pan, meter, and panel. The time may vary ..but it's to 1-9 in the summer and 4:30 to 7:00 the remaining 9 months. Peak residential demand times. Power must be too cheap since they haven't switched it off in about two years. Either that or the solenoid in the meter is broken. It saves no electricity. It merely shifts the load.
 
I have to say our electric utility is pretty fair in that regard. I can't remember the power going out anytime in the last 10 years at least. (though most of my lines are underground) The state is big on paying energy incentives too, they're paying to convert the "old" 8' T12 lights in my shop to new 4' T8 bulbs, saving me watts. Not even a tax credit, they're writing me a check up front!

Originally Posted By: Gary Allan
Either that or the solenoid in the meter is broken.

Mine would have "broke" a long time ago.
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