Retrofitting your home with LEDs is one of the simplest ways to reduce overall energy demand.
LIGHTING MAKES UP about 11 percent of the typical home’s energy use. But as homes become more efficient and demand for space heating and cooling drops, the lighting piece of the “pie” becomes more significant. The emergence of LED lighting has transformed the lighting industry over the past several years. The EPA estimates that widespread use of LEDs could save 348 terawatt-hours (TWh) by 2027—the equivalent annual output of 44 large electrical plants.
LEDs, or light emitting diodes, produce differently than old-fashioned incandescent bulbs or compact fluorescent bulbs. LEDs utilize a semi-conductor as the diode; when electricity passes through it, the material lights up. The heat generated is captured in a heat sink. LEDs are much cooler than “conventional” bulbs; they are also much more energy efficient and last much longer. Until recently, applications were limited and LEDs were prohibitively expensive. That has changed, as a quick tour of any big box store will show you. LED lamps (bulbs), can lights and fixtures have become cost competitive, making it easy to retrofit existing fixtures with energy-efficient LEDs.
At the same time, “smart” technology is changing how we think about lighting, and holds the potential for making already efficient lights even more so. Here are some points to consider as you plan your next lighting purchases.
LEDS: Disruptive Technology
For a long time, LEDs were unknown in residential lighting, but were used in electronics and in the marine and aviation industries. More recently, LEDs have been used in traffic signals, vehicle lights and entertainment lighting, including “holiday” lights. Part of the problem was that there is actually no such thing as a “white” LED. Common LED colors include amber, red, green, and blue. In order to “make” white light, different color LEDs are mixed or covered with a phosphor material that converts the color of the light. The phosphor is the yellow material you see on some LED products.
Not only were the first residential LED products expensive, the quality of the light was disappointing. LEDs are directional light sources, which means they emit light in a specific direction, unlike incandescent and compact fluorescent bulbs, which emit light and heat in all directions. For this reason, LED fixtures use light and energy more efficiently in many applications; however, they are also prone to casting a harsh “spotlight,” rather than a diffuse, even light. Another issue was light quality, which was much cooler than the warm incandescent bulbs we grew up with. LED products include a Kelvin rating, which measures the light’s color temperature. In general, lighting in the 2700 to 3000 K range is pleasing to most people; the higher the number, the “whiter” the light. For comparison, incandescent bulbs range between 2700 and 2800 K.
LED choices have expanded rapidly, from can light and bulb retrofits to dedicated LED fixtures that include internal drivers that transform their higher voltage to household voltage. Although LED light quality issues have largely been solved, you still need to be selective. LED bulbs that have earned Energy Star certification are subject to specific requirements designed to replicate the experience you are used to with a standard A-type bulb, so they can be used for a wide variety of applications. A general-purpose LED bulb that is not certified may not distribute light in all directions and could prove to be a disappointment if used in a table lamp.
CFLs: Not Without Issues
Compact fluorescent lights, or CFLs, also produce light differently than incandescent bulbs. In an incandescent, electric current runs through a wire filament and heats the filament until it starts to glow. With a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light, which excites the fluorescent phosphor coating on the inside of the tube, which then emits visible light.
CFLs need a little more energy when they are first turned on, but once the electricity starts moving, CFLs use about 70 percent less energy than incandescent bulbs. Older CFLs used large and heavy magnetic ballasts that caused a buzzing noise in some bulbs. Most CFLs today (and all Energy Star-certified CFLs) use electronic ballasts, which do not buzz or hum.
CFLs used to have cost and light quality advantages over LEDs, but both of those gaps are closing quickly. Without question, LEDs are the lights of the future.
Connected Lighting: Maximizing Efficiencies
Smart lighting can adjust itself to changing light conditions or occupancy; it can also be programmed to turn on an off at certain times. Some smart lights even “learn” occupant behavior and adjust accordingly. Increasingly, connected lights are part of comprehensive energy management systems. In many cases, these lights can be synced to other features or devices—so long as they all speak the same wireless “language.” One example of this is the Caséta Wireless System, offered by Pennsylvania-based Lutron Electronics. Through their mobile app, you can control not only your home’s lighting, but also the position of shades and thermostat settings, creating “scenes”—coordinated actions among various wireless devices—for specific events.
Wireless lighting saves the hassle of having to break through drywall to wire new outlets and switches. If you’re converting to LED lamps or fixtures anyway, this might be a good time to add wireless sensors and controls. AT THE HEART of most home heating systems is a furnace, a boiler or a heat pump. A furnace burns fossil fuel to heat air that’s forced by a blower fan through a series of ducts to the living spaces; a boiler heats water that’s then pumped to a hydronic, or water-based, distribution system. Most heat pumps run on electricity. They don’t create heat, but rather extract it from the air or the ground. Heat pumps are available for use with forced-air and hydronic distribution systems. If you want to minimize your fuel bill, an Energy Star rating is a minimum standard for these appliances.