Clayton Shobu is the owner of Shobu's Refrigeration & Air Conditioning Inc., based in Kaka'ako. He has been in the business of keeping people cool for 23 years. His company's accounts are about 75 percent commercial and 25 percent residential.

Concerns about the economy slowed business this year to the lowest he'd seen in 15 years, Shobu said. "Sometimes, we start getting busy right after tax season," he said.

But, since late May, the temperatures rose and business bounced back. Shobu said that people often wait until the weather gets hot and then turn on an air-conditioner that hasn't run for months. It doesn't work and "then they panic," he said.

He suggests regular maintenance of your air-conditioner — testing it in the spring, turning it on at least monthly and cleaning filters.

Hawaiian Electric Co. spokesman Darren Pai estimates that 12 percent of a typical home's electricity bill pays for air-conditioning.

Even though many of Hawai'i's older homes don't have air-conditioning, the number that do have risen, he said. Nearly 60 percent of homes have some air-conditioning, even if it's the window unit models rather than central or split air-conditioners.

Pai said Hawaiian Electric offers tips on its Web site and in print to encourage customers to use energy efficiently and better manage their electric bills.

Over at Screens & Things, Inc., owner Mike Lum said business isn't driven by the calendar but by the temperature.

"As soon as it starts getting hot," Lum said, "the phones start ringing more because they're feeling it."

Last week, when the temperatures hit the upper 80s, more people called him or showed up to fix screens, buy screen doors or check out their cooling options.

"It has been very, very busy," Lum said. "We're actually quite pleasantly surprised."

He said summer typically is a busier time of year because people are paying a lot more attention to screens and screen doors: "We've got to fix that screen door because it's hot."

Fixing screens is cheaper than buying a new air-conditioner. But Shobu said folks who do want to buy a new air-conditioner should shop around because the more energy-efficient models use less energy than the older ones.

Reach Robbie Dingeman at rdingeman@honoluluadvertiser.com or 535-2429.