June 16 (Reuters) - San Francisco-based R-Zero, a startup formed during the pandemic to make ultraviolet disinfecting machines for commercial and institutional customers, said on Wednesday it raised $41.5 million to help automate its process and make it more efficient. While hospitals have been using UV-C lights for decades to disinfect operating rooms, the technology was not widely adopted because the machinery was expensive, said Ben Boyer, a co-founder of R-Zero. R-Zero, formed in April last year, makes its UV-C light banks on wheels in San Jose. The company said it has booked $15 million in sales to schools, restaurants, senior care facilities, sports arenas and jails, through a subscription model that starts at $17 a day. It plans to unveil a suite of sensors and a small, safe UV-C light machine that turns on automatically when people are in the room, an improvement over its current UV-C light product that turns off when someone enters the room. The company uses software to collect the data and automate the whole process, said Boyer. Boyer said he is confident that a pirate or legacy UV-C maker could not compete with R-Zero even if it was able to replicate some of the company"s devices. “Systems are very hard to copy," he said. Ira Ehrenpreis an early investor in Tesla Inc (TSLA.O) and SpaceX who first invested in R-Zero last year, said technology is disrupting the cleaning industry. “The idea of taking an approach that has been terrible for our planet and equally terrible for the applicators or the folks that have not had a voice to speak up for themselves” and eliminating the chemicals from it, said Ehrenpreis, fit with the goal of his venture capital firm DBL Partners. The latest round brings the total raised by R-Zero to $58 million. It was led by Silicon Valley venture capital firm World Innovation Lab.