Understanding Radio Frequency

We understand that our customers want to be well informed about new technologies, how the smart grid works and how it will change their relationship with the energy they use. Smart meters are one of the most visible components of the smart grid. They are digital meters that contain the ability to communicate with the utility via a two-way network. Smart meters transmit for only a fraction of the day for short durations and actual radio frequency (RF) emissions are actually less than commonly used devices, such as cell phones, laptop computers, baby monitors and microwave ovens.

Silver Spring-enabled smart grid devices have undergone extensive testing and validation during Federal Communications Commission (FCC) equipment authorization. That filing includes Maximum Permissible Exposure (MPE) testing, which can be found here. Our products not only meet the FCC rules but, in actual usage, transmit significantly less frequently.

Comparison of RF Power Density in the Everyday Environment


RF Output Compared to Standing Two Feet From a Smart Meter

Standing in front of an active microwave oven, two feet from the door

550 times more

Holding a walkie-talkie to your head

55 – 4,600 times more

Holding an active cell phone to your head

3.3 – 1,100 times more

Using a laptop computer

1.1 – 2.2 times more

Sitting in a Wi-Fi cyber café

1.1 – 2.2 times more

Source: Health Impacts of Radio Frequency from Smart Meters by California Council on Science and Technology, April 2011

Silver Spring Networks continually monitors regulatory and scientific developments related to human exposure to RF emissions. Silver Spring Networks relies on expert scientific conclusions related to RF exposures and potential health effects. According to the FCC, the Electric Power Research Institute (EPRI) and the California Council on Science and Technology (CCST), no adverse short or long-term health effects have been shown to occur from the radio frequency signals produced by smart meters or other such wireless networks.

In January 2014, the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) published a technical report on RF EMF measurements, Smart Meter Pulse “Highly Unlikely” to Cause Effects.

Regulating Smart Meters vs. Consumer Products

The FCC has established different guidelines for exposure to RF emissions for consumer products and smart meters. Consumer products such as cell phones and laptop computers that are designed to be used in contact with or in close proximity to the human body use specific absorption rate (SAR) as the primary metric for regulating exposure. This measures the rate of energy absorbed in units of watts per kilogram of body mass (W/kg). The FCC guidelines, which were crafted in coordination with the National Council on Radiation Protection and Measurements (NCRP) and the Institute of Electrical and Electronics Engineers (IEEE), has established a safe limit of 1.6 W/kg for mobile phone devices.

 Unlike consumer products, such as cell phones and laptop computers, smart meters are stationary devices that are typically sited on the sides of homes, inside of utility closets, and are often protected by walls separating the device from individuals inside of the residence. The locations of these devices inherently limit general population exposure. Consequently, the FCC created a separate set of guideline for devices that operate at least 8 inches away from human contact. These guidelines use MPE, which is conservatively based on a SAR of 4 W/kg as the measure of exposure.

Smart Meter Devices and the FCC Limits

Based on years of studying whether exposure to radio waves causes adverse health effects, the FCC has adopted MPE limits for radio transmitters of all types, including smart meters. It includes a prudent margin of safety just in case some health effects are too subtle to have been detected. Even so, smart meters operate far below the limit. Using a realistic high-end duty cycle (4%), the MPE level for a typical Silver Spring-enabled residential metering device operating in the unlicensed spectrum 902-928 MHz is 0.01 mW/cm2. This is equivalent to 1.6% of the FCC limit; however, actual results may vary depending on the specific meter integration.

Exposure is based on the transmitter’s power and the distance from the source. In general, doubling your distance cuts the “power density” by a factor of four. That’s a major reason why radio waves from a smart meter, at a distance of 10 feet, are only about one one-thousandth as much as a typical cell phone. That’s also why powerful but distant radio and TV transmitters are not seen as posing any danger.

Exposure of individuals in their smart-meter equipped homes is commonly orders of magnitude less than that which would occur for an individual standing immediately adjacent to and in front of the meter. In measurements performed in six California residences, 99% of the measured peak values were less than 0.8% of the MPE with 90% of the measured values being less than 0.1% of the exposure limit.

Electric Power Research Institute, December 9, 2011

Silver Spring Networks’ Role

Smart meters are a part of the energy information network that connects all devices that generate, distribute, consume and monitor energy.

We are working to bridge the gap between utilities and customers. We believe that consumers should be able to manage their own energy usage. We also believe in reducing the world’s carbon footprint by controlling the amount and the sources of the energy we all use.

Silver Spring Networks is a leading networking platform and solutions that enable utilities to transform the power grid infrastructure into the smart grid, helping utilities to achieve operational efficiencies, reduce carbon emissions and empower their customers with new ways to monitor and manage their energy consumption.

As part of our commitment to deliver the benefits of the smart grid to the world, we are also realizing additional benefits that include:

  • Modernization of our aging electric grid infrastructure:The electrical power industry faces many business challenges surrounding increased demands on an aging infrastructure. The smart grid will increase visibility for utilities into general status of the grid in real time, enabling increased reliability.
  • Saving money and energy:The smart grid will empower consumers to monitor energy usage, conserve energy, save money, and reduce energy costs for the country. It is far less expensive to conserve energy than to generate it.
  • Safety and security:The smart grid will improve national and economic security by reducing our dependence on fossil fuel. 
  • Helping the environment:The smart grid will reduce greenhouse gas emissions and will enable the use of renewable energy and increase the viability of electric vehicles.
  • Economic and job growth:The smart grid creates jobs; it’s essential to upgrade the century-old grid to fuel economic growth.

Additional Information

Federal Communications Commission

Radio Frequency Safety

Radio Frequency Safety FAQs

Q&A about Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields Evaluating

Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields

Federal Drug Administration (FDA)

Radiation Health

Occupational Health & Safety Administration (OHSA)

Radio Frequency and Microwave Radiation

The National Institute for Occupational Safety and Health (NIOSH)

EMF (Electric and Magnetic Fields)

World Health Organization (WHO)

Electromagnetic fields and public health

California Council on Science and Technology (CCST)