There’s a floor lamp in the lobby at Nashua-based Advanced Renewable Energy Company with three different light bulbs – a 60-watt incandescent bulb, a compact fluorescent light bulb and a bulb that contains six tiny LEDs. While this may sound like a setup to a joke, it isn’t.Instead, the lamp demonstrates the efficiency of LEDs, or light-emitting diodes, over other light sources, explains ARC chief executive and co-founder Dr. Kedar Gupta.While all the bulbs emit similarly bright light, the energy savings are evident by touch alone. The metal surrounding the incandescent is hot to the touch, the metal around the CFL warm, while the LED feels cool, like the lobby.LEDs last more than 20 years – compared to one to two years for incandescent bulbs and three to five for CFLs – and use 90 percent less energy than incandescent light.The problem with LEDs is the price tag – the traditional production of sapphire crystals used in LED applications is costly and time-consuming, and commercially available LED light bulbs can cost up to $45, meaning an average household could spend thousands of dollars on bulbs alone.But at ARC’s nondescript headquarters just off 101A in Nashua, Gupta and his wife Renu and their staff of 24 employees have revolutionized this process by designing and manufacturing world-class industrial machines that grow sapphire crystals in a unique manner, significantly driving down the cost of its applications – primarily LED lighting.“We have found the most economic way [to produce the crystals], and we are the only one in the world that does it,” says Gupta. “Everything is assembled here in Nashua, and most of the parts are local.”ARC’s customers – among the biggest companies in the world -- mostly hail from Asia, where they are producing LED lighting that will be affordable and standard in American homes in the next three to five years, predicts Gupta – a prediction that will come true, thanks in part to his own company.“We are trying to make people consume less for the same comfort level,” says Gupta.Unique technologyAs a co-founder and former chief executive of GT Solar, the highly successful Nashua-based manufacturer of equipment used by manufacturers of solar cells and panels that is now a publicly traded company, Gupta has been ahead of the green-industry curve since 1994, when GT Solar was founded.“At that time, nobody was talking about green, but we saw an opportunity to be in a new technology,” says Gupta, who retired from GT Solar in 2006.He didn’t remain in retirement for long, however.“He got bored,” says Renu Gupta, who together with her husband launched ARC Energy in September 2007 as a start-up in their basement, thanks in part to a loan from Citizens Bank as well as customers and investors who trusted the Guptas’ demonstrated business success.ARC has grown from just four employees at the outset to the current two dozen, who include engineers, technicians and manufacturing personnel. The company will continue “hiring at a fairly good pace,” says Kedar Gupta, perhaps not surprisingly, considering it has a significant backlog on orders and has grown five times larger in the past six months alone.“Demand is growing like there is no tomorrow,” he says.And with only three years in business, even President Barack Obama has taken notice of the company, stopping there on a February 2010 trip to Nashua where he talked about job creation.“The technology they’ve created is the only one of its kind in the world,” said the president in a speech at Nashua North High School. “They’re this little business in a condo out on Amherst Street, and they have the potential to revolutionize an industry. Right here in Nashua.”While the Guptas are busy drafting plans for future projects and expansion, they remain tight-lipped, keeping the company Web site in “stealth mode.”While the Guptas have had great business success in the last two decades, Renu Gupta says, it’s important that they remain humble.“We shouldn’t take all the credit. We have a good group of people,” she says, who says the most important thing learned working at GT Solar was how to treat their employees.There is “only one secret,” says her husband: “Treat people right and demand performance.”ARC-Energy also strives to be “very customer-oriented,” says Renu Gupta.“We work with [our customers] very closely,” says Kedar Gupta. “We always want to be ahead in technology. We don’t want to be following somebody. We are not followers.”Citizens Bank’s In Good Company is presented in partnership with NHBR. The series spotlights growing New Hampshire businesses with unique stories to tell.