Wattage for a Gas Water Heater

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According to: http://www.thisoldhouse.com/toh/article/0,,192981-4,00.html
A GAS water heater uses 500 running watts, and 1500 watts to start it.
What the fuck? Gas water heaters dont use ANY electricity......
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(copied from that web page, see second from the bottom)

Coffeemaker: 1,750 running watts, add 0 watts for starting
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On 4/16/2016 12:05 AM, snipped-for-privacy@unlisted.moo wrote:

Some models of gas WH are what's called power vented. They discharge flue gassed through white PVC pipe like newer furnace. In that case, there is an inducer fan motor to feed with power.
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On Saturday, April 16, 2016 at 7:59:46 AM UTC-4, Stormin Mormon wrote:

Plus those models typically use electric power for the controls and ignition, which is probably why it's higher to start it, eg hot surface ignitor, etc.
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No inducer motor will pull 500 watts.
OTOH, 500 watts is about 1700 BTU/hr.
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On Monday, April 18, 2016 at 10:04:30 AM UTC-4, Scott Lurndal wrote:

So what? Are you suggesting that a table for emergency generator sizing is listing the gas heating energy, not the AC power that's used for the blower, ignitor, etc.? Good grief.
As to 500W being high, generator sizing charts are typically on the high side, that has already been noted.
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On 4/18/2016 10:04 AM, Scott Lurndal wrote:

The one or two vented WH, the ventor motor is much less than 500 watts. I suspect the lists contain at least a couple wild guess.
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On 04/15/2016 11:05 PM, snipped-for-privacy@unlisted.moo wrote:

"Watt" is simply the term for the rate of energy transfer, It does not have to be measured in terms of volts x amps.
Interestingly , I just read the autobiography of Lee deForest and at one point in the book referred to the "horsepower" of a radio transmitter.
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On Saturday, April 16, 2016 at 8:48:57 AM UTC-4, philo wrote:

But here they are talking about the electric power.
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On 04/16/2016 08:11 AM, trader_4 wrote:

Oh, I did not read that. Obviously it's wrong then
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On Saturday, April 16, 2016 at 9:25:45 AM UTC-4, philo wrote:

No, obviously it's right, if it's a power vent water heater, which are common today.
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On 04/16/2016 09:01 AM, trader_4 wrote:

If it has an exhaust motor that draws 500 watts when running then it would be about a 2/3 HP motor...I'd think a 1/10th HP motor should be able to move those exhaust gases OK for sure a 1/4 HP motor I'd think.
I was thinking of eventually getting such a water heater but may just go with electric.
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On Saturday, April 16, 2016 at 12:37:20 PM UTC-4, philo wrote:

See my other post. I agree, I think those numbers are high, probably half that or less is more like it.
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That's true, but higher up the page it says "The chart below shows how many watts of **electricity** it takes to run various household appliances". It's about buying a generator and transfer switch.
And how could it use 1000 more watts of gas power for starting than for running? The gas burnt is going to be the same, or close.

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On 04/15/2016 10:05 PM, snipped-for-privacy@unlisted.moo wrote:

Looks pretty accurate to me.
My Lochinvar LVN041G Power Vent Water Heater 40,000 BTU Natural Gas uses 2.7 Amps (~325 Watts)
(measured with a Fluke 902 HVAC Clamp Meter)
and if those facts don't put you to sleep, consider this:
An 8 minute shower causes the heater to run for 26 minutes.
If knew the price per MCF of gas, I could calculate the cost of a shower...but I'm too lazy to go look it up.
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On Sat, 16 Apr 2016 00:05:20 -0400, snipped-for-privacy@unlisted.moo wrote:

Power vent water heaters with no standing pilot use some power to operate - but 500 and 1500 sounds a bit high to me.
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On Saturday, April 16, 2016 at 11:12:11 AM UTC-4, snipped-for-privacy@snyder.on.ca wrote:

It came from a generator sizing chart, which are dubious at best. I agree, it looked high to me too. They also have 800W for a fridge and 400W for a TV. Fridges of the last decade or so use about half that. My new 55" TV uses ~75W. Who knows where their numbers really came from, how old they are, etc. They probably use high end of possible usage for everything. The real issue he had was that he apparently didn't think a gas water heater would use electric, but the power vent type do.
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On 04/16/2016 10:25 AM, trader_4 wrote:
[snip]

I was monitoring the current from my generator that I used after the tornado last May. The first load I connected was the fridge (new side-by-side from late 2008). It was using a little more than 1A (about 150W). I checked it several times,and it never exceeded that. I think my TV (37-inch LCD with fluorescent backlight) is about that too.
[snip]
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On Saturday, April 16, 2016 at 12:38:18 PM UTC-4, Mark Lloyd wrote:

Couple years ago during hurricane Sandy, I had a KillaWatt meter hooked up with a generator too. Monitored a fridge and a freezer, both made within the last 7 years. They kicked up to about 350W when started, then immediately started dropping, down to like ~100W, consistent with what you saw. I also had it on my 5 year old side by side KitchenAid fridge, it pulls ~90W.
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On Sat, 16 Apr 2016 11:12:11 -0400, snipped-for-privacy@snyder.on.ca wrote:

I've never seen such a Water Heater, but I dont doubt they exist. But I agree, no 500 or 1500w for what is a probably a small fan. I've never seen any gas WHR with any electrical connections....
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On Sat, 16 Apr 2016 00:05:20 -0400, snipped-for-privacy@unlisted.moo wrote:

It's a hybrid water heater. When there is gas, it heats the water which powers a dynamo which charges storage batteries. When the gas is interrupted, the batteries heat the water.
When you've got money, it's worth spending money to protect oneself from problems, even less common ones.

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