Electric vs Gas Water Heaters
adkrustic
| Posted in Energy, Heating & Insulation on
I am replacing my old furnace and part of the process is to reline the chimney so the gas water heater will vent. Since it is 10 years old it seems reasonable to replace the water heater also. I can apply the cost of the liner to a new electric water heater and end up paying essentially the cost of installation for the new water heater. I am on a municipal utility tied to Niagara Falls so electricity is .045/kWh, electric cost is not a concern. I have been looking for a downside to the conversion but can’t find one yet. Am I missing something?
Replies
Not much. An electric heater will last longer, among other things. And if you want high efficiency check into the Marathon line (though the high end of any brand will be pretty efficient).
adkrustic.
I went to electric water heaters for several reasons.
First I'm afraid of what the next 20 years will do to the price of gas. There are several sources for electricity in my region. Coal is cheap plentyful and nearby, we are third in the nation with windpower. We have two nuclear power plants, and you never know when and if solar conversion of sun power will become affordable or cheaper..
Thus electricity will have plenty of competition. gas not so..
Second.. the price of even High efficency models is cheap and they are easy to install.
Third the idea of a vent exhausting conditioned air out 24/7/365 offends my conservative nature.. that 4 inch hole doesn't close, even if it has a damper on it that doesn't prevent heated air from rising on out of the house.. what's worse is that you not only lose that heated air. Mother nature hates a vacumm so you are sucking in cold outside air.
Not so much true re: 24/7 loss up the flue if you have a power vented unit that tends to substantially reduce this heat loss.
Clewless1
You didn't read the OP carefully enough.. he was considering relining his chimney in order to use a hot water heater.. <pleasant smile>
uh oh ... yeah, I knew that ... just checking to see if you did. :)
I've been known not to listen very carefully. Maybe he still gleaned a valid thought out of my musings. Maybe not.
Clewless 1
We all make mistakes (well, I have been known to walk on water.....but only in minnesota in the winter <grin> ) You did have some great info and He should thank you.
yaa ... I know yat Meeneesotans walk on vater in vinter! say hi to Bullwinkle when you see him!
Clewless 1
Awww,,,, he's been hanging around Babe the Blue Ox lately and doesn't come down here to the big city at all..
I think this math is correct...?!!
With electricity at $.045/KWH an electric heater is the way to go. Natural gas is probably $15 per therm (1,000,000 BTU) so the price of electric hot water is cheaper. CALCULATION: one KWH of electricity= 3400 BTU, so it would take 295 KWH to equal 1,000,000 BTUs of heat and 295 times $.045=$13.27 which is less than the price of a therm of gas.
Additionally, electric elements are nearly 100 percent efficient vs. 80 to 90 percent for an instantaneous gas heater. Storage losses can be minimized by adding extra insulation to the tank and by installing a timer so that the unit is off during periods of low use. (Even after 12 hours off we get plenty of hot water out of our unheated tank)
FYI A therm is 100,000 Btu, not 1,000,000 ... but your math pans out it looks like, I guess as you say $15/therm ... more like $1.00 to 1.50 (which seems high to me) per therm depending on supplier. ... Gee and gas was just $ 0.30 8 years ago!! ... overselling the electrict to gas switch has closed the gap w/ electrical costs.
Generally electric will likely always be more expensive than natural gas ... Btu for Btu (usable). It depends on the ration of gas, coal, hydro generation.
Your math needs adjustment/tweeking ... I respect your point of view and your intention, though.
I would encourage checking the actual current electric and gas costs to do the math right ... plus consideration of the likely gas appliance efficiency that would be chosen to do an accurate comparison.
Electric is effectively 100% efficient ... gas has a combustion inefficiency depending on the unit chosen.
How would you say electric is 100% efficient? Do you not think the loss at the power plant would reduce that by quite a bit?
It is 100% for what YOU are paying for.Since you are paying for electricity and not coal the effience is what happens from the meter to the hot water.And that is about 99.95% eff, for all practical purposes 100%.Likewise for gas WH it is again the energy at the meter vs how much hot water you get out. It does not include the energy needed to extract the gas or process it or transport it..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Took the words right out of my mouth, Bill. I appreciate that.
I get sick of always hearing about the 'purists' who take the electrical efficiency back to the power plant. While I can respect that (catfish) point of view, the only efficiency we as consumers currently contend with is that from the meter on. As you said, there are inefficiencies in gas production, etc. ... you pay for those when it goes through the meter.
When I talk about my car's gas mileage, I don't go on about the inefficiencies of transporting it thousands of miles using diesel fuel and then the idiocycracies of refinement and then again transporting it via diesel to the filling station and the inefficiency of making a special trip to fill up (or not).
The reality is, the cost of what we purchase pays for any inefficiency associated w/ getting it to us ... so we can thermodynamically and economically only live within the box of our houses. There is a time and place to consider the issues of the inefficiencies of electric power production ... but these ain't one of them. ... 'sides I hail from the PNW where we have no generation inefficiencies (Coolee Dam)... :)
The other factor is that electric WH have much slower recover rates than gas so they are typically sized up to the next standard size.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
And of course the electric service may be two small to support an electric WH, at least without an interlock for the AC and whatnot.
It is an ironic habit of human beings to run faster when we have lost our way. --Rollo May
BillHartmann
Excellant point.. I've kept the temps in my water heaters down in order to take advantage of the slow recovery rates. they currantly are at the minimum temp for a dish washer to operate safely. That way I don't need to add any cold water to the shower or bath to get a nice warm tub or shower..
I have two electric water heaters. One is domestic hot water and one is for infloor radiant heat. the larger tank is for domestic hot water and that way we can take a couple of showers or a shower and a bath without running out of hot water. The smaller tank is for infloor radiant heat. During the heating season I can cross link them together so the added heating elements are available for infloor radiant heat. when it's really cold outsiide (about 20 below) I can kick on a standby forced air furnace and cover the heat losses from all my windows.. thereby making the house warm and toasty. Since I used my old high efficency furnace and even salavaged my old ductwork there was almost no cost in doing so.
Anyway my floors are barefoot warm all winter long and I spend much less than 1/2 of what I did previously in the old house 1/2 this size and before heating costs increased so much.