High-quality TVs are becoming more common in homes around the world, but their costs are starting to climb steeply. Ultra High Definition TVs, also called 4K TVs, can show images with four times the detail of the standard HD screens we’re used to. However, these new 4K TVs use about 30% more energy than regular HD models. According to a report by the Natural Resources Defense Council, if every TV larger than 36 inches in the US switched to 4K with the current average efficiency, the nation’s domestic energy bills could rise by over $1 billion each year.