Smart meters

Smart Meters send data about your electricity use to your electricity company over a radio link.  Some Smart Meters communicate over the cellphone network, while others use a purpose-built network.  Smart Meters that use the cellphone network usually send data back only once per day. Apart from that they only transmit very briefly every hour or two to keep in touch with the cellphone network.  

The radio transmitter operates at low power, and it only transmit intermittently - typically for a daily total of a few minutes.  This means that exposures from a smart meter are very low, especially if the meter is mounted in a metal box on the outside wall of the house.  It is as though someone were outside the house making a brief call on a cellphone a few times per day.  

The graph below shows exposure measurements recorded inside a house, just behind a Smart Meter mounted on the outside wall that sends data over the cellphone network.  The measurements were recorded over two days.  

The red trace shows the times when the meter is transmitting. (When you see the red trace the transmitter in the meter is active.  If you don't see it, the meter is not transmitting.)  Most of the time it is only active about every hour and a half.  During most of these active periods, the total time during which there is some transmitter activity is about four seconds.  

A couple of the red lines look slightly thicker than the others (for example, just after midnight on the second day).  This is when the metering data is being sent.  The total time over which data is transmitted is about 40 seconds.  Altogether, the transmitter was active for just over two minutes per day.  

The blue diamonds show how strong the radio signal is at the point where the measurements were made . The peak exposure was recorded twice per second while the transmitter was active.  The maximum exposure varied between 0.1 and 0.01% of (ie between one to ten thousand times lower than) the limit allowed for the public in the New Zealand exposure Standard

The transmitter does not transmit continuously while the communication is active, so the average exposure over these periods is even lower.  The exposure would be lower still as you move away from the point right behind the meter. 

Last reviewed: 12 October 2023