With increasing interest in green solutions and the ability to measure and monitor energy use not only historically but in real-time, the monitors and meters available on the market are changing.

Simple Hand-Held Meters

At the bottom end of the scale are simple, hand-held meters. These plug into a socket (between the mains and the load) to measure how much electricity the "plug load" uses. They can measure a single appliance or gadget's electricity use or that of a combination working through a strip plug.

These meters vary widely in price, running from very simple models in the $30 range right up to complex, robust and extremely precise models that cost $130 or more. Here is an example of a cheaper product: Kill a Watt Meter .

Whole House Monitors

The next step up is a meter or monitor for the whole home. These come in two main types.

The first type are simpler monitors which tie into your home electrics (whether that's the mains, an individual circuit or a single socket) and provide information on how much electricity is used throughout the home.

The information they display depends on the model, but most will show peak use, average use, real-time use and calculated kWh figures or even costs. Some will connect to a computer to provide even more information and store data for historical statistics. Most are hand-held units.

The second type are more complex "smart" meters or "performance dashboards". These are more like computer performance screens in that they provide real-time statistics, real-time costs and often connect direct to utility providers and (through them) the Internet to provide consumers with daily statistics, behaviour analysis and suggestions to reduce consumption.

While the development of these systems is still a bit of a mess, with different options, standards and features dependent on the manufacturer and/or utility company involved, they signal an important step forward. What we can measure, we can manage better: the more raw data and useful information we can gather about our own behaviour, the easier it is to spot what we're doing wrong and correct it.

Multi-System Monitors

Beyond the top end of these meters providing "normal" utility monitoring are integrated whole-home metering systems that not only keep an eye on electricity use but also watch other statistics, such as water use, gas use and carbon footprint.

At present, these systems are far too expensive to install in every home but they are still impressive as they integrate many of the latest user interface methodology and technology. They provide real-time information on touch-screen devices, hand-held meters and the Internet, categorized by floor, room, circuit, type or other groupings. The data is converted from numbers into engaging and informative graphs, images, lapse-time photography movies and other media that are easily understood by normal people.

They include ad-hoc query systems, can compare historical to current data, can make suggestions to reduce energy use and even allow homeowners to adjust the automated parts of their home systems to work more efficiently. Some will even switch off the lights for you when you