The big advantage of a home energy monitor for a solar water heater owner is that it can measure the electrical consumption of your backup water heating element, in addition to your whole household electricity use.

So you can find out exactly how much it costs to heat your water when the sun isn't up to the task because of cloudy weather, nightfall or high water consumption. This lets you calculate your payback period very accurately and the actual savings you're achieving.

It also gives an indication of the performance of the particular solar water heater that you installed and helps you manage your hot water consumption for maximum savings.

Inefficient installation and system design can also come to light and be improved in conjunction with your installer if you have the performance information at your fingertips.

The bottom line is that there are definite advantages to measuring the performance of your solar water heater as opposed to having it lumped invisibly into your total household electric bill at the end of the month.

Here are some of the solar water heater and heat pump water heater performance results homeowners have measured using the energy monitors on the list below which they were kind enough to share with me.

Using a home energy monitor can lead you to savings of between 5 and 15 percent on your electricity bill in the first year, which in many cases is enough to pay for the device itself (source: Directgov).

Choosing the Right Home Energy Monitor

This list of energy monitoring devices, also sometimes called electricity monitors or power monitors, can be grouped by their connectivity into 3 categories...

Energy monitors that connect to the web and update automatically in real time.

These connect to a PC or Mac via the USB port (some have a manual web update option).

These connect to neither the web nor a computer (display only).

It's important to have a connection to a PC, Mac or to the web because this allows you to measure your electricity consumption over a long period of time and see the results clearly illustrated in graphs and charts.

A real time web energy monitor additionally allows you to see your consumption from anywhere, for example your work computer or your cellphone.

The display only electricity usage monitors are useful to see what you're consuming at that particular moment, such as when you turn on a light, but it's not suitable to keep track of consumption over a long period of time.

If your country isn't listed below it doesn't necessarily mean that you won't be able to get hold of that power supply monitor, just that you will have to import it. First make sure that it will work in your country by contacting the relevant company.

Web Enabled Real Time Energy Monitors

Computer Enabled Electricity Monitors

Display Only Power Monitors