A home energy monitor helps a homeowner keep track of the amount of energy being used either across the entire house or by different appliances in the household. Almost all homes have an energy monitor already installed – often referred to as an electricity meter. It is used by the electric company to determine the amount of energy that is being used by the household for billing purposes. There are also commercial home energy monitor devices which can be used to get a more accurate picture of how much energy is being used by specific devices, or keep a more accurate and real-time check on home energy usage.
Generally, a home energy monitor measures energy usage in kilowatt-hours (kWh), and electric companies bill based on kWh used. The kilowatt hour is a measure of power, or watts, multiplied by an amount of time. Using 1,000 watts for one hour is one kilowatt.
Any item in a house that uses energy adds to the overall kilowatt usage of the household. Large appliances can add significant loads to the energy usage of a house, which will drive up total energy costs. A home energy monitor can be used to easily track down devices and appliances that are adding unnecessary kilowatt hours to the overall household energy usage.
An individual home energy monitor can be used between a device and the power outlet to measure the amount of energy that device is using. This is especially helpful for devices which spend time in standby or sleep mode, as the devices can still use a significant amount of energy while plugged in but turned off. Using a home energy monitor that tracks individual device usage can help a homeowner find which devices are better to unplug after use instead of leaving them plugged in and on standby.
There are also home energy monitors which monitor the entire house instead of individual appliances. These are helpful to get a picture of what the real-time energy use of an entire house is. Like the individual energy monitors, these can be used to determine the kWh usage of individual appliances and devices. If everything in the house that uses electricity is turned off, individual appliances can be turned on and the change in energy use can be observed on the whole home energy monitor.
The most cost effective way to determine home energy use is to use the electricity meter currently installed on the house that the electric company uses to determine the number of kilowatt hours used. Located on the outside of the house, these meters are either analog or digital and report the number of kilowatt hours being used by the house. By powering down all of the devices in the house and turning them on one at a time, the external electricity meter will display only the amount of energy being used by that device.