Connect this meter into your regular home 110V-120V AC power supply outlet and then, connect the outlet plug of grid tie inverter to this meter. Solar Power Meter measures electricity generated in watts and records kWh (unit) of electricity over the time to show you cumulative generation and dollar saving. Easy device to find out how your solar or wind system is performing. You may also use it for power consumption of home electric appliances, and help user reduce the power bill and carbon emissions. Plug the meter to your wall socket and then plug the electric appliances with the meter; it starts to work and shows you Watts taken by the appliance, records kWh (units of electricity) consumed over the time, shows how clean the electricity is by Power Factor, shows Co2 produced for this power and shows the cost to operate. You can set your local electric rate into it to display correct cost.Press a BUTTON (ENERGY/COST) for more than three seconds to set the parameters using UP & Down button. Press the same button again to set. There is RESET red dot for re-setting all the numbers.