<P> Consumers are often poorly informed of the savings of energy efficient products . A prominent example of this is the energy savings that can be made by replacing an incandescent light bulb with a more modern alternative . When purchasing light bulbs, many consumers opt for cheap incandescent bulbs, failing to take into account their higher energy costs and lower lifespans when compared to modern compact fluorescent and LED bulbs . Although these energy - efficient alternatives have a higher upfront cost, their long lifespan and low energy use can save consumers a considerable amount of money . The price of LEDs has also been steadily decreasing in the past five years, due to improvement of the semiconductor technology . Many LED bulbs on the market qualify for utility rebates that further reduce the price of purchase to the consumer . Estimates by the U.S. Department of Energy state that widespread adoption of LED lighting over the next 20 years could result in about $265 billion worth of savings in United States energy costs . </P> <P> The research one must put into conserving energy is often too time consuming and costly for the average consumer, when there are cheaper products and technology available using today's fossil fuels . Some governments and NGOs are attempting to reduce this complexity with ecolabels that make differences in energy efficiency easy to research while shopping . </P> <P> To provide the kind of information and support people need to invest money, time and effort in energy conservation, it is important to understand and link to people's topical concerns . For instance, some retailers argue that bright lighting stimulates purchasing . However, health studies have demonstrated that headache, stress, blood pressure, fatigue and worker error all generally increase with the common over-illumination present in many workplace and retail settings . It has been shown that natural daylighting increases productivity levels of workers, while reducing energy consumption . </P> <P> In warm climates where air conditioning is used, any household device that gives off heat will result in a larger load on the cooling system . Items such as a stove, dish washer, clothes dryer, hot water and incandescent lighting all add heat to the home . Low power or insulated versions of these devices give off less heat for the air conditioning to remove . The air conditioning system can also improve in efficiency by using a heat sink that is cooler than the standard air heat exchanger such as geothermal or water . </P>

1. why do levels of energy consumption differ