Find Kh rating on meter description plate. It will be something like Kh
Take 3600 times Kh times revolutions Watch Black mark on dial. Divide
by the amount of seconds of total revolutions.
Like this 3600 times Kh3.2 = 11520 times revolutions say you checked with
5 W600. divide by seconds if you have 33 seconds the wattage would be
1745.5 watts.... WW
Well there are different meters for different purposes:
1.) Ammeters give you an instant reading of the current flowing
in the circuit at the moment of analysis... While this is a useful
thing for some purposes, demand (current draw) changes as
things cycle on and off so you would have to figure out exactly
what is operating the moment you make your reading...
2.) The equivalent of a mileometer (which most people know as
an ODOMETER) but for electrical usage... That is a watt-hour
meter... Like the one your electrical company uses to measure
how much electricity you have used... Basic home meters
just measure your kWh used but there are commercial meters
which in addition to measuring usage will also indicate what is
called the "peak demand" which can put the user into a different
billing rate depending on what that peak demand is...
3.) What are you looking to do with your watt-hour meter, the
Kill-a-watt meter suggested by others here is only intended to
be used for a single point-of-use measurement... There are other
systems which can cost a whole lot more than $500 which can
measure your electrical use by circuit from your home's electrical
panel and transmit that information to a web-interface to give you
a live breakdown of what electricity is being used in your home...
I used to work in a building where we has quite a number of
E-Mon D-Mon type sub-metering monitors installed on various
types of loads (lighting, HVAC, elevator/escalator) for determining
the actual cost of Common Area Maintenance (CAM) which was
divided up and charged to the tenants at a rate per square foot
of space leased... E-Mon D-Mon monitors were also utilized
to bill for electrical use in individual rooms in a section of the
building which was used for executive office suites where
an individual or business could rent fully equipped and furnished
rooms with a receptionist and administrative support provided...
Think of them like offices in a can, you need another room,
ask for one and if it is available its just a matter of paying more
in rent rather than real estate shopping for a larger office suite
and relocating -- it was a very good option for businesses
just starting out who would quickly outgrow their initial location
and wouldn't be able to hire on a full staff at the outset, assistance
was available at an hourly rate along with other services like
conference rooms and photocopying and preparing and processing
Short answer: The Kill A Watt is a cheap way to go in some cases.
Mine doesn't work on my microwave...just beeps, "overload".
15 amps max.
Longer answer...OK MUCH longer answer...based on a year of
messing around measuring energy consumption.
Mike's metrology rule number 1. If you're not gonna use the
answer, don't bother to ask the question.
For example, if you want to save on your heating bill, turn
DOWN the thermostat. If it's already as low as you can tolerate,
measuring it won't help a bit. If you can tolerate it lower,
you don't need any measurement to know that it will save you
money to turn DOWN the thermostat.
If you can replace a 100W incandescent bulb with a 13W CFL,
the only thing that matters is that you still have some
savings left after you amortize the added cost of the CFL
over its lifetime...which is often WAY shorter than what it
says on the package.
So, why do you want to measure consumption? For most of us
it's an attempt to reduce costs.
Most residential users, at least in the US, pay for WATT-hours.
You want to measure what you pay for.
If you use a clamp-on amp meter and multiply amps by the voltage,
you get VOLT-AMPS. You don't pay for VOLT-AMPS.
The difference is in the power factor. For an incandescent lamp,
the power factor is 1 and Watts == Volt-amps. For everything else,
volt-amps > watts. You pay for watts...at least where I live.
I just plugged a random 13W CFL lamp into a kill a watt.
Read 13 Watts and 20 Volt-amps. That matters to the power grid,
but until they figure out how to charge you for it, you'll be billed
for the 13 watts.
This difference is the basis for the power factor correction scam.
They come out and measure amps on something with a high power factor.
Then they hook up their magic box and the amps read much lower.
What they don't tell you is that the watts is the same and you save
nothing on your power bill. I've asked for the demo on some of those
stating that we'll be using MY watt meter. They never call back.
Kill a watt can measure both volt-amps and watts. I'm wondering about
the crest factor capability. Most older electronics has a high crest
factor. I've not bothered to calculate accuracy on those devices.
Ok, so to use a kill a watt, you need to be able to unplug the device.
That's hard to do for a water heater...which is likely your most hungry
appliance. Ditto for the heater, furnace blower, dishwasher, stove, etc.
Doesn't work on 240V stuff like the dryer or 240V window air conditioner.
The cleanest solution is to monitor the thing that determines your electric
bill...the meter on the side of the house. Blue Line Innovations makes
a wireless gizmo that clamps onto your power meter and reads the rotation
of the wheel, or for electronic meters, the blinking led.
Doesn't have a lot of resolution, but is fun to watch the display
accumulate those pennies. Same device is marketed under other brands.
They even have a wireless receiver that hooks to your computer for logging.
I find it useful for knowing when I've left something turned on.
My attic had 600W of lighting. Showed up clearly on the consumption.
But the real solution was to replace the lights with CFL and
drop the consumption dramatically.
And with a little math, I can tell exactly how much it costs
to take a shower. But I didn't need it to know that shorter showers
You can measure consumption by timing the rotation of the wheel
on your power meter with the device on/off and subtract out the base load.
Once you have the consumption, you can use indirect measurements.
If you measure the time your water heater runs, you can easily
calculate the energy consumed.
I put a flapper on the heater register. Turns on a switch when
the heater fan runs. Knowing how much gas the furnace consumes/hour
and logging the run-time gives an indirect measurement of something
otherwise difficult to measure directly in real time.
My earliest measurements were made with a PalmIII PDA. Just point it
at the electronic power meter and it reads the watts consumed and graphs
it. Doesn't work on the older wheel meters.
I can supply the program to anyone who wants to play with it.
It's crude, but written in basic so it can be modified. Mostly
undocumented, so not for the faint of heart.
Some power companies are moving toward an online service that tracks
usage in real time, or close to it.
Microsoft Hohm is trying to do a similar thing.
But, bottom line is that knowing may not help. Telling your kids
to take shorter showers will probably work for a week...maybe.
Enforcement is the key.
Bottom line: I spent a lot of time tracking energy consumption.
After the novelty wore off, I was left with the same guidance I had
before I started.
Turn down the thermostat,
Take shorter showers,
Get more insulation,
More efficient furnace,
Dry clothes outside,
For the question you asked, go get a kill a watt. ;-)
Here are more than 25 for less than $5.00, and about 200 for less than
Ebay busted my balls and has made it harder and harder for the
small-time seller to do business. First, they took away a seller's
ability to rate the buyers. Then, despite a perfect rating, they
suspended my acct for 6 mos cuz a couple customers happened to comment
my shipping coulda been a bit quicker, like it was my fault the
carrier lost my pkgs. One was due to the winning bidder being in
Europe, despite being plastered all over my sight I would not ship
outside US. Last I heard, ebay had imposed a mandatory shipping time
limit while doing nothing to protect the seller from slimey buyers.
Screw ebay. I use craigslist.
So, Ebay sanctioned you for perceived sleazy selling practices then?
If that's the case, why would you never buy anything from Ebay? Seems like
they go the extra mile to ensure righteous sellers, even if they
over-protect the buyer.
I just got my weekend Newegg.com sale flyer and they have them on sale for
$16.99, free shipping, and no tax. That's a killer deal for anyone that
wants one. I really like mine.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.