Eternaleds has engineered the world’s first liquid-cooled light bulb, the HydraLux-4, as part of their line of LED products designed for maximum efficiency. Their first fluid-filled offering is a 25 watt model, cooled with harmless paraffin oil (higher wattage examples are to be released after the first of the year), and intended for applications such as accent lighting, bedrooms, desk lamps – they can even be used outdoors. Although expensive, these long-lasting bulbs are rated at 35,000 hours (35x longer than incandescent) and consume only four watts of energy. At today’s energy prices, the HydraLux-4 would cost approximately $1.75 per year to operate if used eight hours per day, generating savings of $157 in power and replacement costs. That’s nothing to scoff at.

Unlike typical LED bulbs, the HydraLux-4 gives off 360-degree light and, unlike compact fluorescent bulbs, they contain no mercury. Two hues are available: Warm White and Daylight White. Eternaleds offers a two-year warranty and a thirty-day money back guarantee on these très cool bulbs.

Cost: $35

Video, close-up shot, and diagram of the differences between standard and HydraLux LED bulbs after the jump.