CFLs does not significantly affect their energy-saving benefits for individual consumers, but their use in large numbers, such as in commercial applications or across millions of homes in a distribution system, could require infrastructure upgrades. In such cases, CFLs with low (below 30 percent) total harmonic distortion (THD) and power factors greater than 0.9 should be selected. Infrared signals Electronic devices operated by infrared remote control can interpret the infrared light emitted by CFLs as a signal; this may limit the use of CFLs near televisions, radios, remote controls, or mobile phones. Energy Star certified CFLs must meet FCC standards, and so are required to list all known incompatibilities on the package. Outdoor use CFLs are generally not designed or rated for outdoor use and some will not start in cold weather. CFLs are available with cold-weather ballasts, which may be rated to as low as −28.8 °C (−20 °F). Light output during the first few minutes of operation is limited at low temperatures before reaching full brightness. Cold-cathode CFLs will start and perform in a wide range of temperatures due to their different design. Starting time Incandescent lamps reach full brightness a fraction of a second after being switched on. , CFLs turn on within a second, but many still take time to achieve full brightness. The light color may be slightly different immediately after being turned on. Some CFLs are marketed as "instant on" and have no noticeable warm-up period, but others can take up to a minute to reach full brightness, or longer in very cold temperatures. Some that use a mercury amalgam can take up to three minutes to reach full output. This and the shorter life of CFLs when turned on and off for short periods may make CFLs less suitable for applications such as motion-activated lighting. Hybrid lamps, combining a halogen lamp with a CFL, are available where warm up time is unacceptable. The halogen lamp lights immediately, and is switched off once the CFL has reached full brightness. Health and environmental impact General According to the European Commission Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) in 2008, CFLs may pose an added health risk due to the ultraviolet and blue light emitted. This radiation could aggravate symptoms in people who already suffer skin conditions that make them exceptionally sensitive to light. The light emitted by some single-envelope CFLs at distances