He's the savior with a toothy smile and a toolbox and a love of being a blue-collar man. Michael Bonsby is behind the wheel of a pickup before 8 a.m. the other day because there are folks out there who are crying the air-conditioning blues.

"What happened this past May is we had a colder May than April," says Bonsby, 35, who works for Thos. E. Clark Plumbing, Heating & Air Conditioning in Silver Spring. In the world of the air-conditioning repairman, a cold May can disrupt the fabric of the universe.

Now, with the heat outside hovering around 90, crawling up like a hurt turtle, the humidity making it feel nearly like a hundred, his world has balanced itself once again: "The second week of June the weather broke, and we were swamped with work," he says happily.

"We can make it in this kind of weather. Not a 40-hour week, though. It's been mostly 50-, 60-hour weeks."

He's headed into Adams Morgan, a full day mapped out on the paperwork on his front seat. The urban renaissance in the District has Bonsby feeling downright giddy. "There are no bad neighborhoods in D.C. anymore," he says. "There are places where you have pockets where hoodlums are. But the city is actually booming."

If he's over in Southeast, on U Street, he'll stop and get something to eat. "I'll be the only white boy in the restaurant. I've never had one problem working in D.C."

James Ostheimer, 28, a research engineer, is waiting at the top of the stairs of his Adams Morgan condo. He looks as if he wants to hug Bonsby. "I didn't know how to clean the air coils," he says. "I've done a lot of research on the Internet the last couple of days. I'm worried the air coils are dirty and I don't have enough Freon," he goes on, referring to a refrigerant.

Upstairs, Bonsby brushes by him and begins taking apart the unit. He pulls out some gadgets. Ostheimer is still crying the blues, complaining about the previous owner, and a contracting company. "I just might end up with a window unit before you know it," he says, sighing.

After looking at the unit, which is behind a wall in the bedroom, Bonsby goes out on the roof, where a heat pump is humming. There's standing water a couple of inches deep, and his sneakers are immediately soaked. He pulls out more tools.

"I had a great day," Ostheimer offers about the previous day. "Came home. The satellite TV wasn't working. Came upstairs to mess with the satellite out on the roof and realized the roof was leaking. And it was 80 degrees in my house." He's got a PhD in astronomy from the University of Virginia. He refused to believe a doggone air conditioner could outsmart him. So he got some tools out and started tinkering. "What can I say? It's in my nature." His tinkering got him nowhere, so he picked up the phone and called Thomas E. Clark.

Eventually, Bonsby comes in from the roof. "I think we have an indoor unit that doesn't match the outdoor unit," he says. "There's definitely a performance problem." One of those just-what-I-figured looks crosses Ostheimer's face. Bonsby will have to return with another part. "Let me get my checkbook," Ostheimer says. "I have to be comfortable. I will pay to be comfortable."

Bonsby graduated from Montgomery Blair High School in 1988. He started out training to be a plumber. He realized he didn't like plumbing, so he became an apprentice in heating and air conditioning. "Air conditioning work to me seems to be easier than heat work. It's lighter work." Still, he once hung a gadget on his belt loop that tells how much walking he does during a day on the job. "I walk 10 miles a day -- from top units to back and forth from the basements."

He and his wife, Nanette, have twin 3-year-old daughters, Samantha and Bridgette. He keeps a stack of pictures of them in plastic on the front seat.

He's back in the pickup now, heading to Chevy Chase. He's scanning apartment buildings and homes through the window, commenting about the air-conditioning units. "Those window units over there are nothing more than rattle units," he says, looking up at one large apartment building on Connecticut Avenue. Already, he's sweaty and he's got oil stains on his fingertips.

"This is a good city to be a blue-collar worker in," he says. "It's a white-collar town! There's huge money in this town for people like me." For a moment, he gets wistful: "I wouldn't mind working in some of those big houses out in Potomac. But everything is just more challenging working in the city."

Jill Watson is standing in her Chevy Chase living room, crying the air-conditioning blues. "In the evenings it started to not work," she says. "We were flooding downstairs. There were gallons of water coming out of the air conditioner and heating unit. It's been the humidity these past few days that's already been oppressive."

Bonsby is already down in the basement, on his hands and knees, peering with a flashlight around the furnace. He has to check the evaporator coil. "The air flow is off right now," Bonsby concludes. He dashes outside to the front yard condenser. After removing some parts, he determines it needs cleaning and a part needs to be replaced. Watson shrugs her shoulders. Her husband, Richard, arrives home and joins the discussion. Soon he is shrugging his shoulders as well: The travails of living where the heat travels like a turtle. The Watsons discuss the upcoming weather as predicted by the forecasters:

"Humid," she says.

"Right into the weekend," he adds.

The repairman breaks for lunch. A pulled-pork sandwich and a glass of lemonade. It's freezing inside the pickup. Life is good. "We got apprentices coming out of school, 23, 24 years old, making $50,000 a year."

He's in LeDroit Park now. Allen Nesbitt, a 29-year-old researcher for America Coming Together, a political organization, purchased his house back in February. "The air conditioning has never worked in this house," he says. A dog is yelping. "When it got to 90, we had to finally put a window unit in the master bedroom," Nesbitt allows. "I called Mike [Bonsby] out of the blue."

In time, Nesbitt says, he realized that the air-conditioning unit was too big for the house. "That causes all kinds of problems," he says, sharing the information he has uncovered. "They also didn't put in enough vents for that oversized system." Bonsby is at the dining room table, tabulating figures. Then he is crouching in the attic, looking at air ducts. He is back downstairs, looking at the ceiling. Thirty minutes have passed, and Bonsby tells Nesbitt that massive taking apart and putting back together will have to be done. Nesbitt says his girlfriend can't take the heat inside the home anymore. He agrees to a follow-up from Bonsby.

Minutes later, loading his toolbox and small ladder into his pickup, Bonsby says of Nesbitt's air-conditioning unit: "It's a disaster. He's looking at a $10,000 repair job."

The savior smiles into the heat. "What can you do?" And off he rolls.

Repairman Michael Bonsby gives Jill Watson the bad news about her air-conditioning unit: It won't be cooling her Chevy Chase house without a cleaning and a new part.