When the temperatures start getting this hot, the phones start ringing at Central Oregon Heating and Cooling in Redmond. "Yes, it's been really, really busy," Lindsey Lands, a dispatcher with the company, said Friday. AC techs are kicking into high gear, working around the clock to keep up with demand. "This week, with this 90-degree weather, it's been non-stop all week," said technician Adam Good. From sunup to sundown, 10- to 12-hour work days have become the norm. And with temperatures forecast in the 90s for at least the next week, there's no end in sight -- which isn't always a bad thing. "It's kind of cliche, but it's how we make our money is this kind of weather, whether it's extremely hot or extremely cold," Good said. There are some things you can do to prevent a major repair during the heat: change your air filters regularly, keep your thermostat around 75 degrees to make sure the unit doesn't overdo it -- and maybe the most important, keep up with maintenance. "A regular maintenance program is huge on these things," Good said, because it saves the life of the unit. Because it's better to find a $20 part that's out than a whole system because of a filter not being changed."