their inefficiency. However, this heat contributes toward heating the room, thereby either reducing heating demand or increasing cooling demand. The overall energy savings from changing to more efficient lighting depends on the climate. In warm climates, efficient lighting has the additional energy-saving effect of reducing the amount of cooling required. In cold climates, increased heating energy demand may offset some of the lighting energy saved with efficient lighting. A report published in January 2008 found that in Los Angeles, where incandescent lighting results in increased air conditioning, electricity savings would pay for the initial cost of CFLs four times faster than in Vancouver, where incandescent lighting contributes to space heating. The report claimed that due to outdoor lighting and air conditioning use in summer months, there is a net cost saving from changing to compact fluorescent lighting in all climates. The cost of CFL and LED bulbs has decreased greatly since 2008, which shortens the time needed to pay off their initial cost. The excessive heat produced by incandescent light bulbs is frequently seen as a drawback, but it is seen as an advantage in certain applications. For example, automotive applications in cold climates benefit from the radiated heat as it melts potentially visually-obstructive snow and ice on warning lights and signs. The heat is also used to melt the wax inside lava lamps. Dimmability Some CFLs are not compatible with existing dimming circuits such as those using TRIACs, although CFLs that support dimming are available. Halogen bulbs provide a somewhat more efficient dimmable alternative to common incandescent bulbs, although they too have been or will be phased out in many places. Many LED bulbs are not dimmable. While dimmable ones using different drivers are available, they may not work well with traditional dimmers - either the dimming range is narrow (the minimum brightness is too high) or the bulb flickers at lower brightness, or even both. The color temperature of incandescent bulbs – essentially the actual temperature of the hot filament – decreases as the voltage applied is reduced by a dimmer, and the light becomes visibly "warmer"; this does not happen with other technologies. However, Philips has designed LED bulbs that mimic this phenomenon when dimmed. See also Electron stimulated luminescence Phase-out of lightweight plastic bags References External links BBC News Online: Light bulbs: Not such a bright idea (February 2006) Save the Bulb: Reasons against the Phase-Out