[lotuseclat79]

Has anyone here bought one of these meters? Looks like a good idea to monitor the consumption of the energy your electric devices while not turned on, and while in use as well. Does Lowe's or Home Depot sell them?

You'll have to google for them to see what price they are going for - found one at $19.99 and another at $29.95 and also at somewhere just above $50.

Read about the device in a NY Times article, Putting Energy Hogs in the Home on a Strict Low-Power Diet, here.

The Department of Energy estimates that in the average home, 40 percent of all electricity used to power home electronics is consumed while the products are turned off. Add that all up, and it equals the annual output of 17 power plants, the government says.

-- Tom

[kiwiguy]

I consult occasionally in this area. The profile of domestic power use has changed radically in the last 20 years.

In history, when appliances were "off", there was little or no load drawn, so "low load" periods were almost "no load" periods.

Appliances were relatively inefficient, so "high load" periods were quite high.

Now its all changed, as most appliances are in "standby" instead of "off", and consume a small but still material amount of power. It's all to do with people getting impatient and wanting instant response from appliances and appliances being fitted with electronic clocks which lose their settings when turned off.

On the other hand, many new appliances tend to be more efficient in use now, so peak loads have not increased to any material degree and may have decreased.

But the usage in terms of monthly kWh grows mainly due to the background standby load. If you can identify all such load and turn it off, savings can be made.

In NZ we have this device available, you program it to $ per hour and it gives an instantaneous and 10 second updated cost of the whole house load.
http://www.centameter.co.nz/

I recommend their use to get an understanding of what uses the power in a house.

[JohnWill]

This device measures the whole house power consumption, which isn't always the information you want. I like the Kill-A-Watt device because you can measure the draw from a single appliance or device. I see they say that they say:

The CENTAMETER is sensitive enough to register the savings made by switching off a single 25-watt light.

This seems to indicate that you can't really tell the difference between the "standby" of a typical LCD panel and power off, for instance. My LCD screens consume 2-3 watts in standby...

Of course, the price of this device will put a few people off too.

[kiwiguy]

I also have an in-line monitor that I built from a kit, it will record a cumulative load and display it as load in watt-hours or in $.

As it uses a commercial metering chip it will measure down to about 10 mA of load current (2 or 3 watts at 230 volts)

The kit cost was similar to the Centameter (which incidentally is only $130 NZ trade, or $US90)

[JohnWill]

I bought the Kill-A-Watt for $20, and it's been handy a time or two. I'm not sure I'd get much use out of one that measured my whole house.

Of course, I have 400A service and three heat pumps to heat/cool a 5000sq/ft house, and there is a LOT of electrical equipment here. Finding 25 watts wouldn't do much for me, I need something to cut big chunks of usage out.

[kiwiguy]

400 amps?

Must be that woossy 110v supply that you use over there...

You need a real mains supply, 230v (or 415v 3 phase) that we have as standard here.

Some supplies are now running at 3 phase 690 volts, where submersible deep well irrigation pumps are used that are 200 metres straight down.

[hewee]

Where you get Kill-A-Watt for $20 at?

[kiwiguy]

http://www.resellerratings.com/forum...hreadid=127772

[JohnWill]

Originally Posted by kiwiguy

400 amps?

Must be that woossy 110v supply that you use over there...

You need a real mains supply, 230v (or 415v 3 phase) that we have as standard here.

Some supplies are now running at 3 phase 690 volts, where submersible deep well irrigation pumps are used that are 200 metres straight down.

Actually, my incoming power is 400A of 240 VAC. There is a neutral line that comes from the center-tap on the transformer to deliver the 120 VAC to each leg of 240 VAC feed.

[JohnWill]

Originally Posted by hewee

Where you get Kill-A-Watt for $20 at?

It was a sale that showed up on one of the bargain sites I regularly visit. It was shipped free as well.

[kiwiguy]

Originally Posted by JohnWill

Actually, my incoming power is 400A of 240 VAC. There is a neutral line that comes from the center-tap on the transformer to deliver the 120 VAC to each leg of 240 VAC feed.

I am seriously pleased not to have to pay your electric bill!

We have dual secondary single phase supplies here, most small or rural distribution transformers can supply 240-N-240 (or 480 v), but 480v equipment rarely (if ever) exists, so the transformers are strapped to parallel the windings and double the current.

I would find (after 40+ years) that 120 volt cabling would be too bulky, as the currents are too high.

Common GP outlets here are wired in 2.5mm cross section copper stranded (old imperial 7/.029). Good for about 25 amps with close protection, or a 5.8 kW load per circuit. Common domestic network connections are 60 amp rated.

[hewee]

Originally Posted by JohnWill

It was a sale that showed up on one of the bargain sites I regularly visit. It was shipped free as well.

Ok thanks

[JohnWill]

Originally Posted by kiwiguy

I am seriously pleased not to have to pay your electric bill!

Sure, but I don't have any other heating bills, since it's an all-electric house.

We have dual secondary single phase supplies here, most small or rural distribution transformers can supply 240-N-240 (or 480 v), but 480v equipment rarely (if ever) exists, so the transformers are strapped to parallel the windings and double the current.

I would find (after 40+ years) that 120 volt cabling would be too bulky, as the currents are too high.

Standard 110V wiring is #14 wire for 15A circuits and #12 wiring for 20A circuits. One issue of 220V wiring to outlets it the lethality is significantly higher, and we have enough people electrocuting themselves here already!

Common GP outlets here are wired in 2.5mm cross section copper stranded (old imperial 7/.029). Good for about 25 amps with close protection, or a 5.8 kW load per circuit. Common domestic network connections are 60 amp rated.

We have many 220V connections for large appliances, but there's really no need to supply a table lamp with a 5.8kw circuit.

I'm surprised that they use stranded wire, all the stationary wiring in the US is normally solid wire. Stranded is only used for extensions from the wall outlet to the device in question in the US.

[hewee]

See How do I find out how much electricity something uses?

[kiwiguy]

Stranded wire is used for all but lighting circits which are solid.
But it's not a fine strand, only a 7 core strand.
Our industry is highly regulated, but DIY is OK if an electrician signs off on the compliance.

And we have almost no fatalities on 230v, either trade or DIY persons.

Most fatalities are on 11,000, 33,000, 66,000, 220,000 or 500,000 distribution or transmission lines, due to errors in work practices. Not much left to bury...